Add development instructions and scripts to README.

* Different shapes for larks/robins: robins are now domes, larks still
   triangles.
 * Related: partners the same color (might try very close colors?)
 * Attempt to have a color scheme so Ones are warm colors and Twos are
   cool colors to make neighbor vs. shadow interactions more clear at a
   glance.

.gitignore

@@ -1,2 +1,2 @@
-www/js/*.js
-www/js/*.js.map
+www/js/**/*.js
+www/js/**/*.js.map

README.md

@@ -6,3 +6,34 @@ early in development and only works on a single dance, Isaac Banner's
 ["Two Hearts in Time"](https://contradb.com/dances/2014), chosen as a
 simple dance (i.e. single progression improper, no shadow or
 next/previous neighbor interactions).
+
+
+## Development
+
+To develop locally, you need
+[TypeScript](https://www.typescriptlang.org/download/) installed. You
+can check if you have the **`tsc`** (TypeScript Compiler) command available.
+
+While developing, leave the [watch-tsc.sh](./watch-tsc.sh) script running
+or, equivalently, run the following the command from the root of the
+repository:
+```sh
+tsc --watch
+```
+
+Also, serve the `www/` directory from a local webserver.
+The [serve.sh](./serve.sh) script will do this or you can run the
+following command from the `www/` directory of the repository:
+```sh
+python -m http.server --bind localhost 8085
+```
+(Nothing special about [Python](https://www.python.org/downloads/) here,
+just the easiest web server to set up.)
+
+Then open http://localhost:8085/ in a web browser. The site should work
+in any modern browser (tested in Firefox and Chromium).
+
+Any text editor/IDE works, but I find
+[VS Code](https://code.visualstudio.com/Download)'s
+[TypeScript support](https://code.visualstudio.com/Docs/languages/typescript)
+works well.

serve.sh

@@ -0,0 +1,7 @@
+#!/bin/sh
+
+# Change directory to www/ directory.
+cd "$(dirname "$0")/www/" || exit
+echo "Serving $(pwd)"
+# From www/
+python -m http.server --bind localhost 8085

watch-tsc.sh

@@ -0,0 +1,7 @@
+#!/bin/sh
+
+# Change directory to repo root.
+cd "$(dirname "$0")" || exit
+echo "Watching $(pwd)"
+# From /
+tsc --watch

www/index.html

@@ -58,29 +58,58 @@
         position: sticky;
         top: 0;
       }
-      th.Ones.Lark {
-        background-color: hsl(0, 80%, 50%);
+
+      th.Ones {
+        background-color: hsl(27, 99%, 59%);
       }
-      td.Ones.Lark {
-        background-color: hsl(0, 90%, 70%);
+      td.Ones {
+        background-color: hsl(27, 99%, 85%);
       }
-      th.Ones.Robin {
-        background-color: hsl(39, 80%, 50%);
+      th.Twos {
+        background-color: hsl(249, 42%, 57%);
       }
-      td.Ones.Robin {
-        background-color: hsl(39, 90%, 70%);
+      td.Twos {
+        background-color: hsl(249, 52%, 85%);
       }
-      th.Twos.Lark {
-        background-color: hsl(240, 70%, 65%);
+
+      th.Lark::before {
+        content: "◠";
+        text-decoration: line-through;
+        padding-right: 1ex;
       }
-      td.Twos.Lark {
-        background-color: hsl(240, 90%, 80%);
+      th.Robin::before {
+        content: "△";
+        padding-right: 1ex;
       }
-      th.Twos.Robin {
-        background-color: hsl(180, 80%, 50%);
+
+      td.Lark.Ones {
+        background:
+          radial-gradient(circle at bottom left, hsl(27, 99%, 75%) 15%, transparent 16%),
+          radial-gradient(circle at bottom right, hsl(27, 99%, 75%) 15%, transparent 16%),
+          hsl(27, 99%, 85%);
+        background-size: 6em 3em;
       }
-      td.Twos.Robin {
-        background-color: hsl(180, 90%, 70%);
+      td.Lark.Twos {
+        background:
+          radial-gradient(circle at bottom left, hsl(249, 42%, 75%) 15%, transparent 16%),
+          radial-gradient(circle at bottom right,hsl(249, 42%, 75%) 15%, transparent 16%),
+          hsl(249, 52%, 85%);
+        background-size: 6em 3em;
+      }
+
+      td.Robin.Ones {
+        background:
+          linear-gradient(45deg,hsl(27, 99%, 75%) 10%, transparent 10%),
+          linear-gradient(135deg, transparent 90%,hsl(27, 99%, 75%) 90%),
+          hsl(27, 99%, 85%);
+        background-size: 6em 3em;
+      }
+      td.Robin.Twos {
+        background:
+          linear-gradient(45deg,hsl(249, 42%, 75%) 10%, transparent 10%),
+          linear-gradient(135deg, transparent 90%,hsl(249, 42%, 75%) 90%),
+          hsl(249, 52%, 85%);
+        background-size: 6em 3em;
       }
 
       .move {

www/js/animation.ts

@@ -98,6 +98,8 @@ export class LinearAnimationSegment extends AnimationSegment {
 
 export interface AnimationTransitionFlags {
   rotation?: boolean;
+  rotationDuring?: "Actual" | "Start" | "End";
+  rotationDirection?: Hand;
   hands?: boolean;
   handsDuring?: "Actual" | "None" | "Start" | "End" | Map<Hand, Offset>;
 }
@@ -125,20 +127,30 @@ export class TransitionAnimationSegment extends AnimationSegment {
     this.startRotation = this.startPosition.rotation;
     this.endRotation = this.endPosition.rotation;
     if (this.flags.rotation) {
+      let rotationDirection = flags.rotationDirection;
+
+      if (!flags.rotationDirection) {
         const actualStart = this.actualAnimation.interpolateRotation(0);
         const actualEnd = this.actualAnimation.interpolateRotation(1);
 
+        if (actualEnd > actualStart) {
+          rotationDirection = Hand.Right;
+        } else if (actualEnd < actualStart) {
+          rotationDirection = Hand.Left;
+        }
+      }
+
       const transitionStart = this.actualAnimation.interpolateRotation(this.startTransitionProgress);
       const transitionEnd = this.actualAnimation.interpolateRotation(1 - this.endTransitionProgress);
 
-      if (actualEnd > actualStart) {
+      if (rotationDirection === Hand.Right) {
         while (transitionStart <= this.startRotation - 180) {
           this.startRotation -= 360;
         }
         while (transitionEnd >= this.endRotation + 180) {
           this.endRotation += 360;
         }
-      } else if (actualEnd < actualStart) {
+      } else if (rotationDirection === Hand.Left) {
         while (transitionStart >= this.startRotation + 180) {
           this.startRotation += 360;
         }
@@ -147,7 +159,9 @@ export class TransitionAnimationSegment extends AnimationSegment {
         }
       }
 
-      // Transitions should be short adjustments, not spins.
+      if (!this.flags.rotationDirection) {
+        // Transitions should be short adjustments, not spins...
+        //  ... unless a direction is explicitly specified.
         while (transitionStart - this.startRotation < -180) {
           this.startRotation -= 360;
         }
@@ -162,12 +176,17 @@ export class TransitionAnimationSegment extends AnimationSegment {
         }
       }
     }
+  }
 
   override interpolateOffset(progress: number): Offset {
     return this.actualAnimation.interpolateOffset(progress);
   }
 
   override interpolateRotation(progress: number): number {
+    switch (this.flags.rotationDuring) {
+      case undefined:
+      case "Actual":
+
         const actualRotation = this.actualAnimation.interpolateRotation(progress);
 
         if (this.flags.rotation) {
@@ -179,6 +198,21 @@ export class TransitionAnimationSegment extends AnimationSegment {
         }
 
         return actualRotation;
+
+      case "Start":
+        if ((1 - progress) < this.endTransitionProgress) {
+          return interpolateLinear((1 - progress) / this.endTransitionProgress, this.endRotation, this.startRotation);
+        } else {
+          return this.startRotation;
+        }
+
+      case "End":
+        if (progress < this.startTransitionProgress) {
+          return interpolateLinear(progress / this.startTransitionProgress, this.startRotation, this.endRotation);
+        } else {
+          return this.endRotation;
+        }
+    }
   }
 
   override interpolateHandOffset(progress: number, hand: Hand): Offset | undefined {
@@ -218,7 +252,21 @@ export class TransitionAnimationSegment extends AnimationSegment {
   }
 
   override drawDebug(ctx: CanvasRenderingContext2D, progress: number) {
-    // TODO display transition somehow?
+    // TODO better way to display transition?
+    if (progress < this.startTransitionProgress) {
+      ctx.beginPath();
+      ctx.moveTo(this.startPosition.position.x, this.startPosition.position.y);
+      const transitionStart = this.actualAnimation.interpolateOffset(this.startTransitionProgress);
+      ctx.lineTo(transitionStart.x, transitionStart.y);
+      ctx.stroke();
+    } else if (progress > 1 - this.endTransitionProgress) {
+      ctx.beginPath();
+      const transitionEnd = this.actualAnimation.interpolateOffset(this.endTransitionProgress);
+      ctx.moveTo(transitionEnd.x, transitionEnd.y);
+      ctx.lineTo(this.endPosition.position.x, this.endPosition.position.y);
+      ctx.stroke();
+    }
+
     this.actualAnimation.drawDebug(ctx, progress);
   }
 }
@@ -227,7 +275,8 @@ export class TransitionAnimationSegment extends AnimationSegment {
 export enum RotationAnimationFacing {
   Linear = "Linear", // Default, linearly interpolate.
   Center = "Center", // Always face the center.
-  CenterRelative = "CenterRelative", // Always face the center.
+  CenterRelative = "CenterRelative",
+  CenterRelativeOffset = "CenterRelativeOffset",
   Forward = "Forward", // Always face the direction of the rotation.
   Backward = "Backward", // Opposite of forward.
   Start = "Start", // Stay facing the same direction as at the beginning.
@@ -337,6 +386,8 @@ export class RotationAnimationSegment extends AnimationSegment {
           return this.startFacing;
         case RotationAnimationFacing.Center:
           return degrees - 90;
+        case RotationAnimationFacing.CenterRelativeOffset:
+          return degrees - 90 + this.centerRelativeTo;
         case RotationAnimationFacing.CenterRelative:
           return degrees - this.startRotation + this.centerRelativeTo;
         case RotationAnimationFacing.Forward:
@@ -392,6 +443,16 @@ export class RotationAnimationSegment extends AnimationSegment {
                 start, end,
                 this.endRotation < this.startRotation);
     ctx.stroke();
+
+    const startPos = this.interpolateOffset(0);
+    const endPos = this.interpolateOffset(1);
+
+    ctx.beginPath();
+    ctx.ellipse(startPos.x, startPos.y, 0.1, 0.1, 0, 0, 2*Math.PI);
+    ctx.stroke();
+    const endSize = 0.05;
+    ctx.fillRect(endPos.x - endSize, endPos.y - endSize, endSize*2, endSize*2);
+
   }
 }
 

www/js/interpreterCommon.ts

@@ -33,6 +33,16 @@ export class CirclePosition {
     this.enumValue = enumValue;
   }
 
+  public static fromSides(leftRightSide: CircleSide.Left | CircleSide.Right, topBottomSide: CircleSide.Bottom | CircleSide.Top) {
+    return leftRightSide === CircleSide.Left
+      ? topBottomSide === CircleSide.Top
+        ? CirclePosition.TopLeft
+        : CirclePosition.BottomLeft
+      : topBottomSide === CircleSide.Top
+        ? CirclePosition.TopRight
+        : CirclePosition.BottomRight;
+  }
+
   private static enumValueToNumber(enumValue: CirclePositionEnum) : number {
     switch (enumValue) {
       case CirclePositionEnum.TopLeft:
@@ -95,6 +105,38 @@ export class CirclePosition {
     ][CirclePosition.enumValueToNumber(this.enumValue)];
   }
 
+  public toShortLines(slideTo: Hand) : ShortLinesPosition {
+    return slideTo === Hand.Left
+      ? [
+        ShortLinesPosition.FarLeft,
+        ShortLinesPosition.MiddleLeft,
+        ShortLinesPosition.FarRight,
+        ShortLinesPosition.MiddleRight,
+      ][CirclePosition.enumValueToNumber(this.enumValue)]
+      : [
+        ShortLinesPosition.MiddleLeft,
+        ShortLinesPosition.FarLeft,
+        ShortLinesPosition.MiddleRight,
+        ShortLinesPosition.FarRight,
+      ][CirclePosition.enumValueToNumber(this.enumValue)];
+  }
+
+  public unfoldToShortLines(center: CircleSide.Bottom | CircleSide.Top) : ShortLinesPosition {
+    return center === CircleSide.Bottom
+      ? [
+        ShortLinesPosition.FarLeft,
+        ShortLinesPosition.MiddleLeft,
+        ShortLinesPosition.MiddleRight,
+        ShortLinesPosition.FarRight,
+      ][CirclePosition.enumValueToNumber(this.enumValue)]
+      : [
+        ShortLinesPosition.MiddleLeft,
+        ShortLinesPosition.FarLeft,
+        ShortLinesPosition.FarRight,
+        ShortLinesPosition.MiddleRight,
+      ][CirclePosition.enumValueToNumber(this.enumValue)];
+  }
+
   public swapDiagonal() : CirclePosition {
     return this.swapAcross().swapUpAndDown();
   }
@@ -220,6 +262,16 @@ export class ShortLinesPosition {
     ][ShortLinesPosition.enumValueToNumber(this.enumValue)];
   }
 
+  public shift(dir: Hand, facing: Facing.Up | Facing.Down): ShortLinesPosition {
+    const shift = (dir === Hand.Left) === (facing === Facing.Down) ? -1 : +1;
+    const newNum = ShortLinesPosition.enumValueToNumber(this.enumValue) + shift;
+    if (newNum < 0 || newNum > 3) {
+      throw new Error("Invalid shift: " + this + " facing " + facing + " to " + dir + ".");
+    }
+
+    return ShortLinesPosition.get(ShortLinesPosition.numberToEnumValue(newNum));
+  }
+
   public isMiddle() : boolean {
     return this.enumValue === ShortLinesPositionEnum.MiddleRight || this.enumValue === ShortLinesPositionEnum.MiddleLeft;
   }
@@ -234,6 +286,11 @@ export class ShortLinesPosition {
     return this.leftRightSide() === CircleSide.Left;
   }
 
+  // Of the two positions on the same leftRightSide() is this the one further to the left?
+  public isLeftOfSide() : boolean {
+    return this.enumValue === ShortLinesPositionEnum.FarLeft || this.enumValue === ShortLinesPositionEnum.MiddleRight;
+  }
+
   public facingSide() : Facing.Left | Facing.Right {
     return this.isLeft() === this.isMiddle() ? Facing.Left : Facing.Right;
   }
@@ -304,7 +361,14 @@ export enum DancerDistance {
   SwingRobin = "SwingRobin",
 }
 export enum LongLines {
+  // Walked forward into center.
   Forward = "Forward",
+
+  // Only a little offset (has walked almost all the way from the other side after a give and take).
+  Near = "Near",
+
+  // Actually in center. May be slightly offset for wavy lines.
+  Center = "Center",
 }
 export type SemanticPosition = {
   kind: PositionKind.Circle,
@@ -325,6 +389,7 @@ export type SemanticPosition = {
   hands?: Map<Hand, HandConnection>,
   balance?: BalanceWeight,
   dancerDistance?: DancerDistance,
+  longLines?: undefined,
 };
 
 export const handsInCircle = new Map<Hand, HandConnection>([
@@ -337,7 +402,7 @@ export const handsInCircle = new Map<Hand, HandConnection>([
     hand: Hand.Left,
   }],
 ]);
-export const handsFourImproper: Map<DancerIdentity, SemanticPosition> = new Map<DancerIdentity, SemanticPosition>([
+export const handsFourImproper: Map<DancerIdentity, SemanticPosition & { kind: PositionKind.Circle }> = new Map<DancerIdentity, SemanticPosition & { kind: PositionKind.Circle }>([
   [DancerIdentity.OnesLark, {
     kind: PositionKind.Circle,
     which: CirclePosition.TopLeft,
@@ -363,3 +428,38 @@ export const handsFourImproper: Map<DancerIdentity, SemanticPosition> = new Map<
     hands: handsInCircle,
   }],
 ]);
+
+export function handsInShortLine({ which, facing, wavy }: { which: ShortLinesPosition; facing: Facing.Up | Facing.Down; wavy: boolean; }): Map<Hand, HandConnection> {
+  return which.isMiddle() ? new Map<Hand, HandConnection>([
+    [Hand.Left, { hand: wavy ? Hand.Right : Hand.Left, to: HandTo.DancerLeft }],
+    [Hand.Right, { hand: wavy ? Hand.Left : Hand.Right, to: HandTo.DancerRight }],
+  ]) : new Map<Hand, HandConnection>([
+    which.isLeft() === (facing === Facing.Up)
+      ? [Hand.Left, { hand: wavy ? Hand.Right : Hand.Left, to: HandTo.DancerLeft }]
+      : [Hand.Right, { hand: wavy ? Hand.Left : Hand.Right, to: HandTo.DancerRight }]
+  ]);
+}
+export function handsInLine(args: { wavy: boolean, which: ShortLinesPosition | CirclePosition, facing?: Facing }) {
+  if (args.which instanceof ShortLinesPosition && (args.facing === Facing.Up || args.facing === Facing.Down)) {
+    return handsInShortLine({ wavy: args.wavy, which: args.which, facing: args.facing });
+  } else {
+    return new Map<Hand, HandConnection>([
+      [Hand.Left, { hand: args.wavy ? Hand.Right : Hand.Left, to: HandTo.DancerLeft }],
+      [Hand.Right, { hand: args.wavy ? Hand.Left : Hand.Right, to: HandTo.DancerRight }],
+    ]);
+  }
+}
+export function handToDancerToSideInCircleFacingAcross(which: CirclePosition): Map<Hand, HandConnection> {
+  return new Map<Hand, HandConnection>([
+    which.isOnLeftLookingAcross()
+      ? [Hand.Right, { hand: Hand.Left, to: HandTo.DancerRight }]
+      : [Hand.Left, { hand: Hand.Right, to: HandTo.DancerLeft }]
+  ]);
+}
+export function handToDancerToSideInCircleFacingUpOrDown(which: CirclePosition): Map<Hand, HandConnection> {
+  return new Map<Hand, HandConnection>([
+    which.isOnLeftLookingUpAndDown()
+      ? [Hand.Right, { hand: Hand.Left, to: HandTo.DancerRight }]
+      : [Hand.Left, { hand: Hand.Right, to: HandTo.DancerLeft }]
+  ]);
+}

www/js/libfigureMapper.ts

@@ -40,7 +40,7 @@ type chooser_dancers = "everyone" | "gentlespoon" | "gentlespoons" | "ladle" | "
 type chooser_pair = "gentlespoons" | "ladles" | "ones" | "twos" | "first corners" | "second corners";
 type chooser_pair_or_everyone = "everyone" | "gentlespoons" | "ladles" | "ones" | "twos" | "first corners" | "second corners";
 type chooser_pairc_or_everyone = "everyone" | "gentlespoons" | "ladles" | "centers" | "ones" | "twos";
-export type chooser_pairz = "gentlespoons" | "ladles" | "partners" | "neighbors" | "next neighbors" | "ones" | "twos" | "same roles" | "first corners" | "second corners" | "shadows";
+export type chooser_pairz = "gentlespoons" | "ladles" | "partners" | "neighbors" | "next neighbors" | "3rd neighbors" | "ones" | "twos" | "same roles" | "first corners" | "second corners" | "shadows";
 type chooser_pairz_or_unspecified = "" | "gentlespoons" | "ladles" | "partners" | "neighbors" | "ones" | "twos" | "same roles" | "first corners" | "second corners" | "shadows";
 type chooser_pairs = "partners" | "neighbors" | "same roles" | "shadows";
 type chooser_pairs_or_ones_or_twos = "partners" | "neighbors" | "same roles" | "ones" | "twos" | "shadows";

www/js/lowLevelMove.ts

@@ -3,7 +3,7 @@ import * as common from "./danceCommon.js";
 import { DanceRole, DancerIdentity, Rotation } from "./danceCommon.js";
 import { BalanceWeight, CirclePosition, CircleSide, CircleSideOrCenter, DancerDistance, Facing, HandConnection, HandTo, LongLines, PositionKind, SemanticPosition, ShortLinesPosition, StarGrip, handsInCircle } from "./interpreterCommon.js";
 import { Move } from "./libfigureMapper.js";
-import { DancerSetPosition, Hand, Offset, OffsetPlus, OffsetRotate, OffsetTimes, OffsetTranspose, dancerHeightOffset, dancerWidth, lineDistance, offsetZero, setDistance, setHeight, setSpacing, setWidth } from "./rendererConstants.js";
+import { DancerSetPosition, Hand, Offset, OffsetPlus, OffsetRotate, OffsetTimes, OffsetTranspose, dancerHeight, dancerHeightOffset, dancerWidth, lineDistance, offsetZero, setDistance, setHeight, setSpacing, setWidth } from "./rendererConstants.js";
 
 
 export enum SemanticAnimationKind {
@@ -88,6 +88,9 @@ export type SemanticAnimation = {
 
   // Swings are asymmetric. This is usually but not always the dancer's role.
   swingRole: common.DanceRole,
+
+  // After a take need to fixup the position.
+  afterTake: boolean,
 } | {
   kind: SemanticAnimationKind.TwirlSwap,
 
@@ -270,8 +273,12 @@ function SemanticToSetPosition(semantic: SemanticPosition): DancerSetPosition {
           throw "Invalid circle position: " + semantic.which;
       }
       switch(semantic.longLines) {
+        case LongLines.Center:
+          position.x *= 0.1;
         case LongLines.Forward:
-          position.x *= 0.25;
+          position.x *= 0.3;
+        case LongLines.Near:
+          position.x *= 0.6;
       }
       let balanceOffset: Offset = offsetZero;
       if (semantic.balance) {
@@ -359,6 +366,10 @@ function SemanticToSetPosition(semantic: SemanticPosition): DancerSetPosition {
           case HandTo.DiagonalAcrossCircle:
             // TODO Is "diagonal" even enough information?
             return { x: -0.5, y: +0.5 }
+          case HandTo.LeftDiagonalAcrossCircle:
+            return { x: -0.5 - setDistance, y: +0.5 }
+          case HandTo.RightDiagonalAcrossCircle:
+            return { x: -0.5 + setDistance, y: +0.5 }
           default:
             throw "Unkown connection: " + connection.to;
         }
@@ -372,12 +383,15 @@ function SemanticToSetPosition(semantic: SemanticPosition): DancerSetPosition {
       };
 
     case PositionKind.ShortLines:
+      let yOffset = 0;
       switch (semantic.facing) {
         case Facing.Up:
           rotation = Rotation.Up;
+          yOffset = +dancerHeight;
           break;
         case Facing.Down:
           rotation = Rotation.Down;
+          yOffset = -dancerHeight;
           break;
         case Facing.Left:
           rotation = Rotation.Left;
@@ -391,16 +405,16 @@ function SemanticToSetPosition(semantic: SemanticPosition): DancerSetPosition {
 
       switch (semantic.which) {
         case ShortLinesPosition.FarLeft:
-          position = { x: -1.5, y: 0 };
+          position = { x: -1.5, y: yOffset };
           break;
         case ShortLinesPosition.MiddleLeft:
-          position = { x: -0.5, y: 0 };
+          position = { x: -0.5, y: yOffset };
           break;
         case ShortLinesPosition.MiddleRight:
-          position = { x: +0.5, y: 0 };
+          position = { x: +0.5, y: yOffset };
           break;
         case ShortLinesPosition.FarRight:
-          position = { x: +1.5, y: 0 };
+          position = { x: +1.5, y: yOffset };
           break;
         default:
           throw "Invalid circle position: " + semantic.which;
@@ -443,12 +457,14 @@ function SemanticToSetPosition(semantic: SemanticPosition): DancerSetPosition {
         // TODO Hands. Might need more info? Or need context of nearby dancer SemanticPositions?
         if (!connection) return undefined;
 
-        const balanceYOffset = semantic.balance === BalanceWeight.Forward ? -shortWavesBalanceAmount : semantic.balance === BalanceWeight.Backward ? shortWavesBalanceAmount : 0;
+        const balanceYOffset = (semantic.facing === Facing.Up ? yOffset : -yOffset)
+          + (semantic.balance === BalanceWeight.Forward ? -shortWavesBalanceAmount : semantic.balance === BalanceWeight.Backward ? shortWavesBalanceAmount : 0);
+        const balanceXOffset = semantic.balance === BalanceWeight.Left ? -balanceAmount : semantic.balance === BalanceWeight.Right ? balanceAmount : 0;
         switch (connection.to) {
           case HandTo.DancerLeft:
-            return { x: -0.5, y: balanceYOffset };
+            return { x: -0.5 + balanceXOffset, y: balanceYOffset };
           case HandTo.DancerRight:
-            return { x: +0.5, y: balanceYOffset };
+            return { x: +0.5 + balanceXOffset, y: balanceYOffset };
           case HandTo.DancerForward:
             if (hand === connection.hand) {
               return { x: 0, y: +0.5 };
@@ -509,12 +525,13 @@ function animateLowLevelMoveWithoutSlide(move: LowLevelMove): animation.Animatio
         ];
       case SemanticAnimationKind.Linear:
         let rotation = endSetPosition.rotation - startSetPosition.rotation;
+        let rotationDuring: boolean = true;
         const minRotation = move.movementPattern.minRotation;
         try {
           rotation = common.normalizeRotation(rotation, minRotation);
         } catch {
-          throw new Error("Expected zero rotation, but start and end positions at different orientations: start="
-            + JSON.stringify(move.startPosition) + ", end=" + JSON.stringify(move.endPosition));
+          rotation = common.normalizeRotation(rotation, undefined);
+          rotationDuring = false;
         }
         return [
           new animation.TransitionAnimationSegment({
@@ -529,19 +546,28 @@ function animateLowLevelMoveWithoutSlide(move: LowLevelMove): animation.Animatio
             flags: {
               hands: (move.movementPattern.handsDuring ?? "Linear") !== "Linear",
               handsDuring: move.movementPattern.handsDuring === "Linear" ? undefined : move.movementPattern.handsDuring,
+              rotation: !rotationDuring,
+              rotationDuring: rotationDuring ? undefined : "Start",
             },
             startTransitionBeats: 1,
         }),
         ];
       case SemanticAnimationKind.Circle:
+      case SemanticAnimationKind.Star:
         if (move.startPosition.kind !== PositionKind.Circle) {
-          throw "Circle must start and end in a circle.";
+          throw new Error(move.movementPattern.kind + " must start and end in a circle.");
         }
 
-        const posWithHands = SemanticToSetPosition({...move.endPosition, hands: handsInCircle})
-        const circleHands = new Map<Hand, Offset>([
+        const isCircle = move.movementPattern.kind === SemanticAnimationKind.Circle;
+        const posWithHands = SemanticToSetPosition({...move.endPosition, hands: isCircle ? handsInCircle : undefined})
+        const circleHands = move.movementPattern.kind === SemanticAnimationKind.Circle ? new Map<Hand, Offset>([
           [Hand.Left, posWithHands.leftArmEnd!],
           [Hand.Right, posWithHands.rightArmEnd!],
+        ]) : new Map<Hand, Offset>([
+          [move.movementPattern.hand, {
+            x: (move.movementPattern.hand === Hand.Right ? +1 : -1) * (1 + (move.movementPattern.grip === StarGrip.HandsAcross ? 0 : 0.15)) * Math.sqrt(2),
+            y: move.movementPattern.grip === StarGrip.HandsAcross ? 0 : 0.25
+          }]
         ]);
 
         return [
@@ -556,7 +582,7 @@ function animateLowLevelMoveWithoutSlide(move: LowLevelMove): animation.Animatio
                 width: setWidth,
                 height: setHeight,
               },
-              facing: animation.RotationAnimationFacing.Center,
+              facing: isCircle ? animation.RotationAnimationFacing.Center : animation.RotationAnimationFacing.Forward,
               closer: undefined,
               hands: new Map<Hand, animation.HandAnimation>([
                 [Hand.Left, { kind: "End" }],
@@ -564,6 +590,7 @@ function animateLowLevelMoveWithoutSlide(move: LowLevelMove): animation.Animatio
               ])
             }),
             flags: {
+              rotation: true,
               hands: true,
               handsDuring: circleHands,
             },
@@ -646,18 +673,35 @@ function animateLowLevelMoveWithoutSlide(move: LowLevelMove): animation.Animatio
         const rotateSwingCenter = CenterOf(move.movementPattern.around, move.startPosition.setOffset, move.startPosition.lineOffset);
         const dancerDistance = move.movementPattern.swingRole === DanceRole.Lark ? DancerDistance.SwingLark : DancerDistance.SwingRobin;
 
-        const swingStart = SemanticToSetPosition({
+        const baseSwingStart = {
           ...move.startPosition,
-          dancerDistance,
+          dancerDistance: move.movementPattern.afterTake ? undefined : dancerDistance,
           balance: undefined,
-        });
+          longLines: undefined,
+        }
+        const swingStartUnadjusted = SemanticToSetPosition(move.startPosition.longLines === LongLines.Near ? {
+          ...baseSwingStart,
+          kind: PositionKind.Circle,
+          which: move.startPosition.which.swapUpAndDown(),
+        } : baseSwingStart);
+        const swingStart = move.movementPattern.afterTake
+          ? {
+            ...swingStartUnadjusted, position: {
+              x: swingStartUnadjusted.position.x
+                + ((move.startPosition.longLines === LongLines.Near) === (move.startPosition.which.isLeft())
+                  ? +0.5
+                  : -0.5),
+              y: rotateSwingCenter.y,
+            }
+          }
+          : swingStartUnadjusted;
         const beforeUnfold = SemanticToSetPosition({
           ...move.endPosition,
           dancerDistance,
         });
         const unfolded = SemanticToSetPosition({
           ...move.endPosition,
-          dancerDistance: DancerDistance.Normal,
+          dancerDistance: move.endPosition.dancerDistance === DancerDistance.Compact ? DancerDistance.Compact : DancerDistance.Normal,
           hands: move.movementPattern.swingRole === DanceRole.Lark
             ? new Map<Hand, HandConnection>([[Hand.Right, {hand: Hand.Left, to: HandTo.DancerRight}]])
             : new Map<Hand, HandConnection>([[Hand.Left, {hand: Hand.Right, to: HandTo.DancerLeft}]]),
@@ -669,15 +713,16 @@ function animateLowLevelMoveWithoutSlide(move: LowLevelMove): animation.Animatio
         const turns = Math.ceil(Math.abs(move.movementPattern.minAmount / 360));
         const swingMinRotation = (minTurns - turns) * (move.movementPattern.minAmount < 0 ? -360 : 360) + move.movementPattern.minAmount;
 
-        return [
-          new animation.TransitionAnimationSegment({
+        const slideAmount = move.movementPattern.afterTake ? { x: 0, y: rotateSwingCenter.y - startSetPosition.position.y  } : undefined;
+
+        const swingAnimation = new animation.TransitionAnimationSegment({
             actualAnimation: new animation.RotationAnimationSegment({
               beats: swingBeats,
-              startPosition: startSetPosition,
-              endPosition: beforeUnfold,
+              startPosition: slideAmount ? { ...swingStart, position: OffsetPlus(swingStart.position, OffsetTimes(slideAmount, -1)) } : swingStart,
+              endPosition: slideAmount ? { ...beforeUnfold, position: OffsetPlus(beforeUnfold.position, OffsetTimes(slideAmount, -1)) } : beforeUnfold,
               rotation: swingMinRotation,
               around: {
-                center: rotateSwingCenter,
+                center: slideAmount ? OffsetPlus(rotateSwingCenter, OffsetTimes(slideAmount, -1)) : rotateSwingCenter,
                 width: 1,
                 height: 1,
               },
@@ -685,8 +730,8 @@ function animateLowLevelMoveWithoutSlide(move: LowLevelMove): animation.Animatio
                 minDistance: 1,
                 transitionBeats: 1,
               },
-              facing: animation.RotationAnimationFacing.CenterRelative,
-              centerRelativeTo: startSetPosition.rotation + ((move.startPosition.facing === Facing.Up || move.startPosition.facing === Facing.Down) === (dancerDistance === DancerDistance.SwingLark) ? -45 : +45)
+              facing: animation.RotationAnimationFacing.CenterRelativeOffset,
+              centerRelativeTo: (dancerDistance === DancerDistance.SwingLark ? -45 : +45),
             }),
             flags: {
               rotation: true,
@@ -695,7 +740,14 @@ function animateLowLevelMoveWithoutSlide(move: LowLevelMove): animation.Animatio
             },
             startTransitionBeats: 1,
             endTransitionBeats: 0,
-          }),
+          });
+
+        return [
+          slideAmount ? new animation.SlideAnimationSegment(
+            swingAnimation.beats,
+            [swingAnimation],
+            slideAmount,
+          ) : swingAnimation,
           new animation.LinearAnimationSegment({
             beats: 1,
             startPosition: beforeUnfold,
@@ -711,6 +763,7 @@ function animateLowLevelMoveWithoutSlide(move: LowLevelMove): animation.Animatio
         const twirlCenter =
           CenterOf(move.movementPattern.around, move.startPosition.setOffset, move.startPosition.lineOffset);
         const aroundTopOrBottom = move.movementPattern.around === CircleSide.Top || move.movementPattern.around === CircleSide.Bottom;
+        const inShortLines = move.startPosition.kind === PositionKind.ShortLines;
         return [
           new animation.TransitionAnimationSegment({
             actualAnimation: new animation.RotationAnimationSegment({
@@ -727,7 +780,7 @@ function animateLowLevelMoveWithoutSlide(move: LowLevelMove): animation.Animatio
               around: {
                 center: twirlCenter,
                 width: aroundTopOrBottom ? setWidth : setWidth / 4,
-                height: aroundTopOrBottom ? setHeight / 4 : setHeight,
+                height: aroundTopOrBottom || inShortLines ? setHeight / 4 : setHeight,
               },
               facing: animation.RotationAnimationFacing.Linear,
               hands: new Map<Hand, animation.HandAnimation>([
@@ -779,6 +832,7 @@ function animateLowLevelMoveWithoutSlide(move: LowLevelMove): animation.Animatio
             flags: {
               hands: true,
               rotation: true,
+              rotationDirection: move.movementPattern.side,
             },
             startTransitionBeats: 0.5,
           })
@@ -838,10 +892,17 @@ function animateLowLevelMoveWithoutSlide(move: LowLevelMove): animation.Animatio
           startTransitionBeats: 1,
         })
         ];
+      case SemanticAnimationKind.Promenade:
+        return [
+          new animation.StepWideLinearAnimationSegment({
+            beats: move.beats,
+            startPosition: startSetPosition,
+            endPosition: endSetPosition,
+            distanceAtMidpoint: setHeight / 2,
+          })
+        ]
       // TODO Unsupported moves, just doing linear for now.
       case SemanticAnimationKind.RollAway:
-      case SemanticAnimationKind.Promenade:
-      case SemanticAnimationKind.Star:
         return [
           new animation.LinearAnimationSegment({
             beats: move.beats,

www/js/main.ts

@@ -146,14 +146,14 @@ wrapperDiv.appendChild(beatDisplay);
 function drawAtCurrentBeat() {
   r.drawSetsWithTrails(beatSlider.valueAsNumber, progressionSelector.valueAsNumber);
 
-  const moveForCurrent = movesByBeat[Math.floor(beatSlider.valueAsNumber)];
-  if (!moveForCurrent.classList.contains('currentMove')) {
+  const moveForCurrent = movesByBeat.at(Math.floor(beatSlider.valueAsNumber));
+  if (!moveForCurrent?.classList.contains('currentMove') ?? false) {
     for (let i = 0; i < movesByBeat.length; i++) {
       if (movesByBeat[i].classList.contains('currentMove')) {
         movesByBeat[i].classList.remove('currentMove');
       }
     }
-    moveForCurrent.classList.add('currentMove');
+    moveForCurrent?.classList.add('currentMove');
   }
 }
 
@@ -289,6 +289,7 @@ function buildMovesList() {
   }
   if (lastItem) {
     lastItem.classList.add('moveForBeat_' + currentBeat);
+    movesByBeat[currentBeat] = lastItem;
   }
 
   if (r.animation.progressionError) {
@@ -420,6 +421,46 @@ displaySettingsDiv.appendChild(document.createElement('br'));
 displaySettingsDiv.appendChild(extraLinesLabel);
 displaySettingsDiv.appendChild(extraLinesSelector);
 
+const trailIncrementsSelector = document.createElement('input');
+trailIncrementsSelector.type = 'number';
+trailIncrementsSelector.min = '0';
+trailIncrementsSelector.step = '1';
+trailIncrementsSelector.value = r.trailIncrements!.toString();
+trailIncrementsSelector.id = 'trailIncrements';
+trailIncrementsSelector.style.width = '3em';
+trailIncrementsSelector.addEventListener('input', (ev) => {
+  r.trailIncrements = trailIncrementsSelector.valueAsNumber;
+  drawAtCurrentBeat();
+  restartAnimation(false);
+})
+const trailIncrementsLabel = document.createElement('label');
+trailIncrementsLabel.innerText = '# trails (faded previous positions): ';
+trailIncrementsLabel.htmlFor = 'trailIncrements';
+
+displaySettingsDiv.appendChild(document.createElement('br'));
+displaySettingsDiv.appendChild(trailIncrementsLabel);
+displaySettingsDiv.appendChild(trailIncrementsSelector);
+
+const trailBeatsSelector = document.createElement('input');
+trailBeatsSelector.type = 'number';
+trailBeatsSelector.min = '0';
+trailBeatsSelector.step = '0.1';
+trailBeatsSelector.value = r.trailLengthInBeats!.toPrecision(1);
+trailBeatsSelector.id = 'trailBeats';
+trailBeatsSelector.style.width = '3em';
+trailBeatsSelector.addEventListener('input', (ev) => {
+  r.trailLengthInBeats = trailBeatsSelector.valueAsNumber;
+  drawAtCurrentBeat();
+  restartAnimation(false);
+})
+const trailBeatsLabel = document.createElement('label');
+trailBeatsLabel.innerText = '# max age of trails (faded previous positions) in beats: ';
+trailBeatsLabel.htmlFor = 'trailBeats';
+
+displaySettingsDiv.appendChild(document.createElement('br'));
+displaySettingsDiv.appendChild(trailBeatsLabel);
+displaySettingsDiv.appendChild(trailBeatsSelector);
+
 displaySettingsDiv.appendChild(document.createElement('br'));
 displaySettingsDiv.appendChild(debugRender);
 displaySettingsDiv.appendChild(debugRenderLabel);
@@ -462,7 +503,7 @@ verifyButton.addEventListener('click', () => {
       libfigureError = 'libfigure ex: ' + e;
     }
     try {
-      progressionError = interpreter.loadDance(dance.figures, dance.start_type).progressionError;
+      progressionError = interpreter.loadDance(dance).progressionError;
       const moveError = [...interpreter.interpretedDance.values()].flatMap(moves => moves.filter(m => m.interpreterError !== undefined).map(m => m.interpreterError)).at(0);
       if (moveError) {
         interpreterError = "interpreter move error: " + moveError;
@@ -537,7 +578,7 @@ function loadDance() {
     danceTitle.appendChild(title);
     danceTitle.appendChild(author);
   }
-  r.animation = interpreter.loadDance(dance.figures, dance.start_type);
+  r.animation = interpreter.loadDance(dance);
   if (cancelAnim !== undefined) {
     cancelAnimationFrame(cancelAnim);
     playButton.innerText = 'Play';

www/js/moves/_moveInterpreter.ts

@@ -0,0 +1,341 @@
+import { CoupleRole, DanceRole, DancerIdentity, ExtendedDancerIdentity } from "../danceCommon.js";
+import { CirclePosition, CircleSideOrCenter, PositionKind, SemanticPosition } from "../interpreterCommon.js";
+import { Move, chooser_pairz } from "../libfigureMapper.js";
+import { LowLevelMove, SemanticAnimation, SemanticAnimationKind } from "../lowLevelMove.js";
+
+type MoveName = string & Move["move"];
+export type MoveInterpreterCtor<N extends MoveName> = new (args: MoveInterpreterCtorArgs<N>) => MoveInterpreter<N>;
+export const moveInterpreters: Map<MoveName, MoveInterpreterCtor<MoveName>> = new Map<MoveName, MoveInterpreterCtor<MoveName>>();
+
+export interface MoveInterpreterCtorArgs<N extends MoveName> {
+  move: Move & { move: N };
+  nextMove: Move;
+  numProgessions: number;
+}
+export type SemanticPositionsForAllDancers = Map<DancerIdentity, SemanticPosition>;
+export interface MoveAsLowLevelMovesArgs {
+  startingPos: SemanticPositionsForAllDancers;
+}
+export type LowLevelMovesForAllDancers = Map<DancerIdentity, LowLevelMove[]>;
+export interface Variant {
+  previousMoveVariant?: string,
+  lowLevelMoves: LowLevelMovesForAllDancers,
+};
+export type VariantCollection = Map<string, Variant>;
+
+export type PartialLowLevelMove = {
+  remarks?: string,
+  beats: number,
+  startPosition?: SemanticPosition,
+  endPosition: SemanticPosition,
+  movementPattern: SemanticAnimation,
+};
+
+export interface ISingleVariantMoveInterpreter {
+  moveAsLowLevelMoves: () => LowLevelMovesForAllDancers;
+  moveAsVariants: () => VariantCollection;
+};
+
+export abstract class SingleVariantMoveInterpreter<T extends MoveInterpreter<N>, N extends MoveName> implements ISingleVariantMoveInterpreter {
+  protected readonly moveInterpreter: T;
+  protected readonly startingPos: SemanticPositionsForAllDancers;
+
+  constructor(moveInterpreter: T, startingPos: SemanticPositionsForAllDancers) {
+    this.moveInterpreter = moveInterpreter;
+    this.startingPos = startingPos;
+  }
+
+  get move() : Move & { move: N } {
+    return this.moveInterpreter.move;
+  }
+
+  abstract moveAsLowLevelMoves(): LowLevelMovesForAllDancers;
+
+  moveAsVariants(): VariantCollection {
+    return new Map<string, Variant>([
+      ["default", { lowLevelMoves: this.moveAsLowLevelMoves() }]
+    ]);
+  }
+
+  static append(moves: LowLevelMove[],
+                newMove: LowLevelMove | PartialLowLevelMove
+                         | ((prevEnd: SemanticPosition) => PartialLowLevelMove)): LowLevelMove[] {
+    const lastMove = moves.at(-1)!;
+    const prevEnd = lastMove.endPosition;
+    if (typeof newMove === 'function') {
+      newMove = newMove(prevEnd);
+    }
+
+    if (!newMove.startPosition) {
+      newMove.startPosition = prevEnd;
+    }
+    moves.push({
+      ...newMove,
+      startPosition: newMove.startPosition ?? prevEnd,
+      move: lastMove.move,
+      startBeat: lastMove.startBeat + lastMove.beats,
+    });
+
+    return moves;
+  }
+
+  combine(moves: ((LowLevelMove | PartialLowLevelMove
+                            | ((prevEnd: SemanticPosition) => PartialLowLevelMove))[]),
+                   startPos?: SemanticPosition): LowLevelMove[] {
+    const res: LowLevelMove[] = [];
+    if (moves.length === 0) return res;
+
+    let firstMove = moves[0];
+    if ('move' in firstMove) {
+      res.push(firstMove);
+    } else {
+      if (typeof firstMove === 'function') {
+        firstMove = firstMove(startPos!);
+      }
+
+      res.push({...firstMove,
+        move: this.move,
+        startBeat: 0,
+        startPosition: firstMove.startPosition ?? startPos!,
+      });
+    }
+
+    for (const move of moves.slice(1)) {
+      SingleVariantMoveInterpreter.append(res, move);
+    }
+
+    if (res[0].startPosition === undefined) {
+      throw new Error("combine() called without a startPosition.");
+    }
+
+    return res;
+  }
+
+  findPairOpposite(who: chooser_pairz, id: DancerIdentity): ExtendedDancerIdentity | null {
+    const pos = this.getPosFor(id.asExtendedDancerIdentity());
+
+    const inSameSet = (proposedId: ExtendedDancerIdentity) => {
+      const proposedPos = this.getPosFor(proposedId);
+      return {
+        ...proposedId,
+        // Get the same role dancer in the set the dancer is currently in.
+        relativeSet: proposedId.relativeSet + (pos.setOffset - proposedPos.setOffset)
+      }
+    }
+
+    switch (who) {
+      case "partners":
+        return id.partner().asExtendedDancerIdentity();
+      case "neighbors":
+      case "next neighbors":
+      case "3rd neighbors":
+        // TODO This isn't quite right... especially if it's "next" to intentionally progress...
+        return inSameSet(id.neighbor().asExtendedDancerIdentity());
+      // These three might get used when not with neighbors?
+      case "gentlespoons":
+      case "ladles":
+      case "same roles":
+        if (who === "gentlespoons" && id.danceRole === DanceRole.Robin
+          || who === "ladles" && id.danceRole === DanceRole.Lark) {
+          return null;
+        }
+        return inSameSet(id.oppositeSameRole().asExtendedDancerIdentity());
+      case "ones":
+        if (id.coupleRole === CoupleRole.Twos) return null;
+        return id.partner().asExtendedDancerIdentity();
+      case "twos":
+        if (id.coupleRole === CoupleRole.Ones) return null;
+        return id.partner().asExtendedDancerIdentity();
+      case "shadows":
+        throw new Error("Not sure shadow is consistently the same.");
+      case "first corners":
+      case "second corners":
+        throw new Error("Contra corners are unsupported.");
+      default:
+        throw new Error("Unsupported who: " + who);
+    }
+  }
+
+  getPosFor(id: ExtendedDancerIdentity): SemanticPosition & { setOffset: number, lineOffset: number } {
+    const basePos = this.startingPos.get(id.setIdentity)!;
+    return {...basePos,
+      setOffset: (basePos.setOffset ?? 0) + id.relativeSet,
+      lineOffset: (basePos.lineOffset ?? 0) + id.relativeLine,
+    };
+  }
+
+  handleMove(dancerFunc: ((arg: { id: DancerIdentity, startPos: SemanticPosition }) => LowLevelMove[])): Map<DancerIdentity, LowLevelMove[]> {
+    const res = new Map<DancerIdentity, LowLevelMove[]>();
+    let anyProgressed = false;
+    for (const [id, startPos] of this.startingPos.entries()) {
+      const lowLevelMoves = dancerFunc({ id, startPos });
+
+      if (this.move.progression) {
+        const startingPos: SemanticPosition = lowLevelMoves.at(0)?.startPosition!;
+        const endPos: SemanticPosition = lowLevelMoves.at(-1)?.endPosition!;
+        if (startingPos.setOffset !== endPos.setOffset) {
+          anyProgressed = true;
+        }
+      }
+
+      res.set(id, lowLevelMoves);
+    }
+
+    if (this.move.progression && !anyProgressed) {
+      for (const [id, lowLevelMoves] of res.entries()) {
+        const startingPos: SemanticPosition = lowLevelMoves.at(0)?.startPosition!;
+        const endPos: SemanticPosition = lowLevelMoves.at(-1)?.endPosition!;
+        if (startingPos.setOffset === endPos.setOffset && endPos.kind === PositionKind.Circle) {
+          const endSetOffset = (endPos.setOffset ?? 0) + (endPos.which.isTop() ? -0.5 : +0.5);
+          const endWhich = endPos.which.swapUpAndDown();
+          lowLevelMoves[lowLevelMoves.length - 1] = {
+            ...lowLevelMoves[lowLevelMoves.length - 1],
+            endPosition: {
+              ...endPos,
+              setOffset: endSetOffset,
+              which: endWhich,
+            }
+          };
+        }
+      }
+    }
+
+    return res;
+  }
+
+  handleCircleMove(dancerFunc: ((arg: { id: DancerIdentity, startPos: SemanticPosition & { kind: PositionKind.Circle } }) => LowLevelMove[])): Map<DancerIdentity, LowLevelMove[]> {
+    return this.handleMove(({ id, startPos }) => {
+      if (startPos.kind !== PositionKind.Circle) {
+        throw new Error(this.move.move + " must start in a circle, but " + id + " is at " + startPos);
+      }
+
+      return dancerFunc({ id, startPos });
+    });
+  }
+
+  handlePairedMove(who: chooser_pairz, dancerFunc: ((arg: {
+    id: DancerIdentity,
+    startPos: SemanticPosition,
+    withPos: SemanticPosition & { setOffset: number, lineOffset: number },
+    withId: ExtendedDancerIdentity,
+    around: CircleSideOrCenter,
+  }) => LowLevelMove[]), meanwhileFunc?: ((arg: {
+    id: DancerIdentity,
+    startPos: SemanticPosition,
+  }) => LowLevelMove[])): Map<DancerIdentity, LowLevelMove[]> {
+    return this.handleMove(({ id, startPos }) => {
+      const withId = this.findPairOpposite(who, id);
+      if (!withId) {
+        if (meanwhileFunc) {
+          return meanwhileFunc({ id, startPos });
+        } else {
+          return this.combine([{
+            beats: this.move.beats,
+            startPosition: { ...startPos, hands: undefined },
+            endPosition: { ...startPos, hands: undefined },
+            // TODO Not sure this is actually a good default...
+            movementPattern: { kind: SemanticAnimationKind.StandStill },
+          }]);
+        }
+      }
+      const withPos = this.getPosFor(withId);
+      const setDifference = withPos.setOffset - (startPos.setOffset ?? 0);
+      let startPosAdjusted = startPos;
+      if (setDifference !== 0) {
+        // TODO Can move be with a different short line or just a different circle?
+        //      PassBy can probably be with the next short line...
+        if (startPos.kind === PositionKind.Circle && (setDifference === 1 || setDifference === -1)) {
+          startPosAdjusted = {
+            ...startPos,
+            setOffset: (startPos.setOffset ?? 0) + setDifference / 2,
+            which: startPos.which.swapUpAndDown(),
+          }
+        } else {
+          throw new Error("Not near dancer to " + this.move.move + " with.");
+        }
+      }
+      const startWhich = startPosAdjusted.which;
+      // TODO Can swing be across the set (top or bottom)?
+      const around = withPos.which.leftRightSide() === startWhich.leftRightSide()
+        ? startWhich.leftRightSide()
+        : withPos.kind === PositionKind.Circle
+          ? (startWhich instanceof CirclePosition && withPos.which.topBottomSide() === startWhich.topBottomSide()
+            ? startWhich.topBottomSide()
+            : "Center")
+          : "Center";
+
+      return dancerFunc({ id, startPos: startPosAdjusted, withId, withPos, around });
+    });
+  }
+
+  handleCirclePairedMove(who: chooser_pairz, dancerFunc: ((arg: {
+    id: DancerIdentity,
+    startPos: SemanticPosition & { kind: PositionKind.Circle },
+    withPos: SemanticPosition & { setOffset: number, lineOffset: number },
+    withId: ExtendedDancerIdentity,
+    around: CircleSideOrCenter,
+  }) => LowLevelMove[]), meanwhileFunc?: ((arg: {
+    id: DancerIdentity,
+    startPos: SemanticPosition & { kind: PositionKind.Circle },
+  }) => LowLevelMove[])): Map<DancerIdentity, LowLevelMove[]> {
+    return this.handlePairedMove(who, ({ id, startPos, withId, withPos, around }) => {
+      if (startPos.kind !== PositionKind.Circle) {
+        throw new Error(this.move.move + " must start in a circle, but " + id + " is at " + startPos);
+      }
+
+      return dancerFunc({ id, startPos, withId, withPos, around });
+    }, meanwhileFunc ? ({id, startPos}) => {
+      if (startPos.kind !== PositionKind.Circle) {
+        throw new Error(this.move.move + " must start in a circle, but " + id + " is at " + startPos);
+      }
+
+      return meanwhileFunc({id, startPos});
+    } : undefined);
+  }
+
+  errorStandStill() {
+    return this.handleMove(({ startPos }) => {
+      return [{
+        interpreterError: "UNKNOWN MOVE '" + this.move.move + "': standing still",
+        move: this.move,
+        startBeat: 0,
+        beats: this.move.beats,
+        startPosition: startPos,
+        endPosition: startPos,
+        movementPattern: {
+          kind: SemanticAnimationKind.StandStill,
+        },
+      }];
+    });
+  }
+}
+
+export abstract class MoveInterpreter<N extends MoveName> {
+  public readonly move: Move & { move: N };
+  public readonly nextMove: Move;
+  public readonly numProgressions: number;
+
+  constructor({ move, nextMove, numProgessions }: MoveInterpreterCtorArgs<N>) {
+    this.move = move;
+    this.nextMove = nextMove; // TODO Should be able to get rid of this using variants.
+    this.numProgressions = numProgessions;
+  }
+
+  abstract buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter;
+
+  moveAsLowLevelMoves({ startingPos }: MoveAsLowLevelMovesArgs): LowLevelMovesForAllDancers {
+    return this.buildSingleVariantMoveInterpreter(startingPos).moveAsLowLevelMoves();
+  }
+}
+
+class DefaultSingleVariantMoveInterpreter extends SingleVariantMoveInterpreter<DefaultMoveInterpreter, MoveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    return this.errorStandStill();
+  }
+}
+class DefaultMoveInterpreter extends MoveInterpreter<MoveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    throw new Error("Method not implemented.");
+  }
+}
+export const errorMoveInterpreterCtor: MoveInterpreterCtor<MoveName> = DefaultMoveInterpreter;

www/js/moves/allemande.ts

@@ -0,0 +1,170 @@
+import { SemanticPosition, PositionKind, CircleSide, Facing, CirclePosition, LongLines, HandConnection } from "../interpreterCommon.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+type allemandeMoves = "allemande" | "allemande orbit" | "gyre";
+
+class AllemandeSingleVariant extends SingleVariantMoveInterpreter<Allemande, allemandeMoves> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    // Need to store this locally so checking move.move restricts move.parameters.
+    const move = this.move;
+
+    const allemandeCircling = move.move === "allemande orbit" ? move.parameters.circling1 : move.parameters.circling;
+    const byHandOrShoulder = (move.move === "gyre" ? move.parameters.shoulder : move.parameters.hand) ? Hand.Right : Hand.Left;
+
+    // TODO Not sure if this is right.
+    const swap = allemandeCircling % 360 === 180;
+    const returnToStart = allemandeCircling % 360 === 0;
+    const intoWave = !swap && !returnToStart && allemandeCircling % 90 == 0;
+    const intoWavePositions = !intoWave ? 0 : (allemandeCircling % 360 === 90) === (byHandOrShoulder === Hand.Left) ? 1 : -1;
+    if (!swap && !returnToStart && !intoWave) {
+      // TODO Support allemande that's not a swap or no-op.
+      throw "Unsupported allemande circle amount: " + allemandeCircling;
+    }
+
+    return this.handlePairedMove(move.parameters.who, ({ startPos, around, withId, withPos }) => {
+      let endPosition: SemanticPosition = startPos;
+      let startingPos = startPos;
+      if (swap) {
+        // TODO This was more complicated. Is this wrong?
+        endPosition = withPos;
+      } else if (intoWave) {
+        if (startPos.kind === PositionKind.ShortLines) {
+          if (around === CircleSide.Left || around === CircleSide.Right) {
+            // Fix startPos if necessary. Needed because pass through always swaps but sometimes shouldn't.
+            let startWhich = startPos.which;
+            if ((startPos.facing === Facing.Up || startPos.facing === Facing.Down) &&
+              ((byHandOrShoulder === Hand.Right)
+                !== (startPos.facing === Facing.Up)
+                !== startPos.which.isLeftOfSide())) {
+              startWhich = startPos.which.swapOnSide()
+              startingPos = {
+                ...startPos,
+                which: startWhich,
+              };
+            }
+
+            const endWhich = CirclePosition.fromSides(startingPos.which.leftRightSide(),
+              startWhich.isLeftOfSide()
+                !== (byHandOrShoulder === Hand.Right)
+                !== (intoWavePositions === 1)
+                ? CircleSide.Top
+                : CircleSide.Bottom);
+            endPosition = {
+              kind: PositionKind.Circle,
+              which: endWhich,
+              facing: (startingPos.facing === Facing.Up) === (intoWavePositions === 1)
+                ? endWhich.facingAcross()
+                : endWhich.facingOut(),
+              setOffset: startingPos.setOffset,
+              lineOffset: startingPos.lineOffset,
+            }
+          } else {
+            throw new Error("Allemande from short lines to line line in middle unsupported.");
+          }
+        } else {
+          if (around === "Center") {
+            const startCenter = startPos.longLines === LongLines.Center;
+            const endWhich = startPos.which.circleRight(intoWavePositions);
+            endPosition = {
+              kind: PositionKind.Circle,
+              which: endWhich,
+              facing: startPos.which.facingOut(),
+              longLines: startCenter ? undefined : LongLines.Center,
+              setOffset: startPos.setOffset,
+              lineOffset: startPos.lineOffset,
+            }
+          } else {
+            const endWhich = startPos.which.toShortLines(intoWavePositions === 1 ? Hand.Right : Hand.Left);
+            endPosition = {
+              kind: PositionKind.ShortLines,
+              which: endWhich,
+              facing: endWhich.isLeftOfSide() === (byHandOrShoulder === Hand.Left) ? Facing.Up : Facing.Down,
+              setOffset: startPos.setOffset,
+              lineOffset: startPos.lineOffset,
+            }
+          }
+        }
+      }
+
+      return this.combine([
+        {
+          beats: move.beats,
+          endPosition,
+          movementPattern: {
+            kind: SemanticAnimationKind.RotateAround,
+            minAmount: byHandOrShoulder === Hand.Right ? allemandeCircling : -allemandeCircling,
+            around,
+            byHand: move.move === "allemande" || move.move === "allemande orbit" ? byHandOrShoulder : undefined,
+            close: true,
+          },
+        },
+      ], {
+        ...startingPos,
+        hands: startPos.hands && move.move !== "gyre"
+          ? new Map<Hand, HandConnection>([...startPos.hands.entries()].filter(([h, c]) => h === byHandOrShoulder))
+          : undefined
+      });
+    }, move.move !== "allemande orbit" ? undefined : ({ id, startPos }) => {
+      const orbitAmount = move.parameters.circling2;
+      const swap = orbitAmount % 360 === 180;
+      if (!swap && orbitAmount % 360 !== 0) {
+        // TODO Support allemande that's not a swap or no-op.
+        throw "Unsupported allemande orbit amount: " + orbitAmount;
+      }
+
+      const startingPos: SemanticPosition = {
+        ...startPos,
+        hands: undefined,
+        balance: undefined,
+        dancerDistance: undefined,
+      }
+      let endPosition: SemanticPosition;
+      if (swap) {
+        if (startingPos.kind === PositionKind.Circle) {
+          endPosition =
+          {
+            ...startingPos,
+            which: startingPos.which.swapDiagonal(),
+            facing: startingPos.which.isLeft() ? Facing.Left : Facing.Right,
+          }
+        } else {
+          endPosition =
+          {
+            ...startingPos,
+            which: startingPos.which.swapSides(),
+            facing: startingPos.which.isLeft() ? Facing.Left : Facing.Right,
+          }
+        }
+      } else {
+        endPosition = startingPos;
+      }
+
+      return this.combine([
+        {
+          beats: move.beats,
+          endPosition,
+          movementPattern: {
+            kind: SemanticAnimationKind.RotateAround,
+            // Orbit is opposite direction of allemande.
+            minAmount: byHandOrShoulder === Hand.Right ? -orbitAmount : +orbitAmount,
+            around: "Center",
+            byHand: undefined,
+            close: false,
+          },
+        },
+      ], startingPos);
+    });
+  }
+}
+
+class Allemande extends MoveInterpreter<allemandeMoves> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new AllemandeSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set("allemande", Allemande);
+moveInterpreters.set("allemande orbit", Allemande);
+moveInterpreters.set("gyre", Allemande);

www/js/moves/balance.ts

@@ -0,0 +1,44 @@
+import { BalanceWeight } from "../interpreterCommon.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, MoveInterpreterCtorArgs, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+class BalanceSingleVariant extends SingleVariantMoveInterpreter<Balance, "balance"> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    return this.handleMove(({ startPos }) => {
+      // TODO Use who to determine facing?
+      // TODO Could be left to right, not back and forth?
+      // TODO How to determine hand... by next move, I guess?
+
+      return this.combine([
+        {
+          beats: this.moveInterpreter.forwardBeats,
+          endPosition: { ...startPos, balance: BalanceWeight.Forward },
+          movementPattern: { kind: SemanticAnimationKind.Linear },
+        },
+        {
+          beats: this.moveInterpreter.backwardBeats,
+          endPosition: { ...startPos, balance: BalanceWeight.Backward },
+          movementPattern: { kind: SemanticAnimationKind.Linear },
+        },
+      ], startPos);
+    });
+  }
+}
+
+class Balance extends MoveInterpreter<"balance"> {
+  public readonly forwardBeats: number;
+  public readonly backwardBeats: number;
+
+  constructor(args: MoveInterpreterCtorArgs<"balance">) {
+    super(args);
+
+    this.forwardBeats = this.move.beats / 2;
+    this.backwardBeats = this.move.beats - this.forwardBeats;
+  }
+
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new BalanceSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set("balance", Balance);

www/js/moves/balanceTheRing.ts

@@ -0,0 +1,56 @@
+import { BalanceWeight, Facing, HandConnection, HandTo, PositionKind, SemanticPosition } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { LowLevelMove, SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+
+export function balanceCircleInAndOut(move: Move, startPos: SemanticPosition, balanceBeats?: number): [LowLevelMove, LowLevelMove] {
+  if (startPos.kind !== PositionKind.Circle) {
+    throw "Balance circle must start in a circle, but starting at " + startPos;
+  }
+
+  balanceBeats ??= 4;
+  const balancePartBeats = balanceBeats/2;
+
+  const holdingHandsInCircle: SemanticPosition = {...startPos,
+    facing: Facing.CenterOfCircle,
+    hands: new Map<Hand, HandConnection>([
+      [Hand.Left, { hand: Hand.Right, to: HandTo.LeftInCircle }],
+      [Hand.Right, { hand: Hand.Left, to: HandTo.RightInCircle }],
+    ]),
+  };
+  const circleBalancedIn: SemanticPosition = {...holdingHandsInCircle,
+    balance: BalanceWeight.Forward,
+  };
+
+  const balanceIn: LowLevelMove = {
+    move,
+    startBeat: 0,
+    beats: balancePartBeats,
+    startPosition: holdingHandsInCircle,
+    endPosition: circleBalancedIn,
+    movementPattern: { kind: SemanticAnimationKind.Linear },
+  };
+  const balanceOut: LowLevelMove = {...balanceIn,
+    startBeat: balancePartBeats,
+    startPosition: circleBalancedIn,
+    endPosition: holdingHandsInCircle,
+  };
+
+  return [balanceIn, balanceOut];
+}
+
+class BalanceTheRingSingleVariant extends SingleVariantMoveInterpreter<BalanceTheRing, "balance the ring"> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    return this.handleCircleMove(({ startPos }) => balanceCircleInAndOut(this.move, startPos));
+  }
+}
+
+class BalanceTheRing extends MoveInterpreter<"balance the ring"> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new BalanceTheRingSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set("balance the ring", BalanceTheRing);

www/js/moves/boxCirculate.ts

@@ -0,0 +1,83 @@
+import { DanceRole, CoupleRole } from "../danceCommon.js";
+import { SemanticPosition, Facing, HandConnection, HandTo, BalanceWeight } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, PartialLowLevelMove, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "box circulate";
+
+class BoxCirculateSingleVariant extends SingleVariantMoveInterpreter<BoxCirculate, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    const circulateRight: boolean = this.move.parameters.hand;
+    const whoCrosses = this.move.parameters.who;
+    return this.handleCircleMove(({ id, startPos }) => {
+      let isCrossing: boolean;
+      switch (whoCrosses) {
+        case "gentlespoons":
+          isCrossing = id.danceRole === DanceRole.Lark;
+          break;
+        case "ladles":
+          isCrossing = id.danceRole === DanceRole.Robin;
+          break;
+        case "ones":
+          isCrossing = id.coupleRole === CoupleRole.Ones;
+          break;
+        case "twos":
+          isCrossing = id.coupleRole === CoupleRole.Twos;
+          break;
+        case "first corners":
+        case "second corners":
+          throw "first/second corner leading box circulate doesn't make sense?";
+      }
+
+      // Starts in long wavy lines.
+      const startingPos: SemanticPosition = {
+        ...startPos,
+        facing: isCrossing === startPos.which.isLeft() ? Facing.Right : Facing.Left,
+        hands: new Map<Hand, HandConnection>([
+          [Hand.Left, { hand: Hand.Left, to: HandTo.DancerLeft }],
+          [Hand.Right, { hand: Hand.Right, to: HandTo.DancerRight }],
+        ]),
+        balance: undefined,
+        longLines: undefined,
+        dancerDistance: undefined,
+      };
+      const balance: PartialLowLevelMove[] = this.move.parameters.bal ? [
+        {
+          beats: 2,
+          endPosition: { ...startingPos, balance: circulateRight ? BalanceWeight.Right : BalanceWeight.Left },
+          movementPattern: { kind: SemanticAnimationKind.Linear },
+        },
+        {
+          beats: 2,
+          endPosition: { ...startingPos, balance: BalanceWeight.Backward },
+          movementPattern: { kind: SemanticAnimationKind.Linear },
+        },
+      ] : [];
+      const circulate: PartialLowLevelMove = {
+        beats: this.move.beats - (this.move.parameters.bal ? 4 : 0),
+        endPosition: {
+          ...startingPos,
+          which: isCrossing ? startingPos.which.swapAcross() : startingPos.which.swapUpAndDown(),
+          facing: isCrossing ? startingPos.facing : startingPos.facing === Facing.Right ? Facing.Left : Facing.Right,
+        },
+        movementPattern: {
+          // TODO Not sure loop should really be linear...
+          kind: SemanticAnimationKind.Linear,
+          minRotation: isCrossing ? undefined : circulateRight ? 180 : -180,
+          handsDuring: "None",
+        }
+      };
+      return this.combine([...balance, circulate], startingPos);
+    });
+  }
+}
+
+class BoxCirculate extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new BoxCirculateSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, BoxCirculate);

www/js/moves/boxTheGnat.ts

@@ -0,0 +1,74 @@
+import { HandConnection, HandTo, BalanceWeight } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, PartialLowLevelMove, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "box the gnat";
+
+class BoxTheGnatSingleVariant extends SingleVariantMoveInterpreter<BoxTheGnat, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    return this.handlePairedMove(this.move.parameters.who, ({ startPos, around, withPos }) => {
+      const hand = this.move.parameters.hand ? Hand.Right : Hand.Left;
+      const balanceBeats = this.move.parameters.bal
+        ? this.move.beats > 4
+          ? this.move.beats - 4
+          : 2
+        : 0;
+      const balancePartBeats = balanceBeats / 2;
+      const twirlBeats = this.move.beats - balanceBeats;
+
+      // TODO Adjust facing?
+      const startPosition = { ...startPos, hands: new Map<Hand, HandConnection>([[hand, { hand, to: HandTo.DancerForward }]]) };
+
+      if (around === "Center") {
+        throw "TwirlSwap around center is unsupported.";
+      }
+
+      const twirl: PartialLowLevelMove = {
+        beats: twirlBeats,
+        endPosition: withPos,
+        movementPattern: {
+          kind: SemanticAnimationKind.TwirlSwap,
+          around,
+          hand,
+        }
+      };
+
+      if (this.move.parameters.bal) {
+        return this.combine([
+          {
+            beats: balancePartBeats,
+            endPosition: {
+              ...startPosition,
+              balance: BalanceWeight.Forward,
+            },
+            movementPattern: {
+              kind: SemanticAnimationKind.Linear,
+            }
+          },
+          {
+            beats: balancePartBeats,
+            endPosition: {
+              ...startPosition,
+              balance: BalanceWeight.Backward,
+            },
+            movementPattern: {
+              kind: SemanticAnimationKind.Linear,
+            }
+          },
+          twirl], startPosition);
+      } else {
+        return this.combine([twirl], startPosition);
+      }
+    });
+  }
+}
+
+class BoxTheGnat extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new BoxTheGnatSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, BoxTheGnat);

www/js/moves/butterflyWhirl.ts

@@ -0,0 +1,33 @@
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "butterfly whirl";
+
+class ButterflyWhirlSingleVariant extends SingleVariantMoveInterpreter<ButterflyWhirl, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    return this.handleCircleMove(({ startPos }) => {
+      return this.combine([{
+        beats: this.move.beats,
+        endPosition: startPos,
+        movementPattern: {
+          kind: SemanticAnimationKind.RotateAround,
+          around: startPos.which.leftRightSide(),
+          // TODO hand around isn't the same as allemande...
+          byHand: startPos.which.isOnLeftLookingAcross() ? Hand.Right : Hand.Left,
+          close: true,
+          minAmount: 360,
+        }
+      }], startPos);
+    });
+  }
+}
+
+class ButterflyWhirl extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new ButterflyWhirlSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, ButterflyWhirl);

www/js/moves/californiaTwirl.ts

@@ -0,0 +1,53 @@
+import { HandConnection, HandTo, CircleSide, Facing } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "California twirl";
+
+class CaliforniaTwirlSingleVariant extends SingleVariantMoveInterpreter<CaliforniaTwirl, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    return this.handleCirclePairedMove(this.move.parameters.who, ({ startPos }) => {
+      // TODO does "who" matter here or is it entirely positional? At least need to know who to omit.
+
+      const onLeft: boolean = startPos.which.isOnLeftLookingUpAndDown();
+      // TODO get rid of this 1 beat set up and make it part of TwirlSwap?
+      return this.combine([
+        {
+          beats: 1,
+          endPosition: {
+            ...startPos,
+            hands: new Map<Hand, HandConnection>([onLeft
+              ? [Hand.Right, { to: HandTo.DancerRight, hand: Hand.Left }]
+              : [Hand.Left, { to: HandTo.DancerLeft, hand: Hand.Right }]]),
+            facing: startPos.which.topBottomSide() === CircleSide.Top ? Facing.Down : Facing.Up,
+          },
+          movementPattern: {
+            kind: SemanticAnimationKind.Linear,
+          }
+        },
+        {
+          beats: this.move.beats - 1,
+          endPosition: {
+            ...startPos,
+            which: startPos.which.swapAcross(),
+            facing: startPos.which.topBottomSide() === CircleSide.Top ? Facing.Up : Facing.Down,
+          },
+          movementPattern: {
+            kind: SemanticAnimationKind.TwirlSwap,
+            around: startPos.which.topBottomSide(),
+            hand: onLeft ? Hand.Right : Hand.Left,
+          }
+        }], startPos);
+    });
+  }
+}
+
+class CaliforniaTwirl extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new CaliforniaTwirlSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, CaliforniaTwirl);

www/js/moves/chain.ts

@@ -0,0 +1,154 @@
+import { DanceRole } from "../danceCommon.js";
+import { HandTo, HandConnection, PositionKind } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "chain";
+
+class ChainSingleVariant extends SingleVariantMoveInterpreter<Chain, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    const mainRole = this.move.parameters.who === "gentlespoons" ? DanceRole.Lark : DanceRole.Robin;
+    const pullToTurnBeats = 2;
+    const pullBeats = this.move.beats / 2 - pullToTurnBeats;
+    const turnBeats = this.move.beats - pullBeats - pullToTurnBeats;
+    const chainHand: Hand = this.move.parameters.hand ? Hand.Right : Hand.Left;
+    const cwCourtesyTurn = chainHand === Hand.Left;
+
+    return this.handleCircleMove(({ id, startPos }) => {
+      if (id.danceRole === mainRole) {
+        const endWhich = startPos.which.swapDiagonal();
+        let endSet = startPos.setOffset ?? 0;
+        let to: HandTo;
+        switch (this.move.parameters.dir) {
+          case "along":
+            throw "Don't know what chaining along the set means.";
+          case "across":
+            to = HandTo.DiagonalAcrossCircle;
+            break;
+          case "right diagonal":
+            to = HandTo.RightDiagonalAcrossCircle;
+            endSet += startPos.which.isLeft() ? -1 : +1;
+            break;
+          case "left diagonal":
+            to = HandTo.LeftDiagonalAcrossCircle;
+            endSet += startPos.which.isLeft() ? +1 : -1;
+            break;
+        }
+        const startPosition = {
+          ...startPos,
+          hands: new Map<Hand, HandConnection>([[chainHand, { hand: chainHand, to }]]),
+          facing: startPos.which.facingAcross(),
+        };
+
+        const turnTo = chainHand === Hand.Right ? HandTo.DancerRight : HandTo.DancerLeft;
+
+        return this.combine([
+          {
+            beats: pullBeats,
+            endPosition: {
+              ...startPos,
+              which: endWhich,
+              facing: endWhich.facingUpOrDown(),
+              setOffset: endSet,
+              hands: new Map<Hand, HandConnection>([
+                [Hand.Left, { hand: Hand.Left, to: turnTo }],
+                [Hand.Right, { hand: Hand.Right, to: turnTo }],
+              ]),
+            },
+            movementPattern: {
+              kind: SemanticAnimationKind.PassBy,
+              around: "Center",
+              side: chainHand,
+              withHands: true,
+              facing: "Forward",
+              otherPath: "Swap",
+            }
+          },
+          {
+            beats: pullToTurnBeats,
+            endPosition: {
+              ...this.startingPos,
+              kind: PositionKind.Circle,
+              which: endWhich.swapUpAndDown(),
+              facing: endWhich.facingOut(),
+              setOffset: endSet,
+            },
+            movementPattern: {
+              kind: SemanticAnimationKind.PassBy,
+              side: chainHand.opposite(),
+              withHands: true,
+              around: endWhich.leftRightSide(),
+              facing: "Forward", // TODO Is this right?
+              otherPath: "Swap",
+            }
+          },
+          prevEnd => ({
+            beats: turnBeats,
+            endPosition: {
+              kind: PositionKind.Circle,
+              which: endWhich,
+              facing: endWhich.facingAcross(),
+              hands: prevEnd.hands,
+              setOffset: prevEnd.setOffset,
+              lineOffset: prevEnd.lineOffset,
+            },
+            movementPattern: {
+              kind: SemanticAnimationKind.CourtesyTurn,
+              clockwise: cwCourtesyTurn,
+            }
+          })
+        ], startPosition);
+      } else {
+        const startingPos = { ...startPos, hands: undefined };
+        return this.combine([
+          {
+            beats: pullBeats,
+            endPosition: { ...startingPos, facing: startingPos.which.facingUpOrDown() },
+            movementPattern: {
+              kind: SemanticAnimationKind.Linear,
+            }
+          },
+          {
+            beats: pullToTurnBeats,
+            endPosition: {
+              ...startingPos,
+              which: startingPos.which.swapUpAndDown(),
+              facing: startingPos.which.facingOut()
+            },
+            movementPattern: {
+              kind: SemanticAnimationKind.PassBy,
+              side: chainHand.opposite(),
+              withHands: true,
+              around: startingPos.which.leftRightSide(),
+              facing: "Forward", // TODO Is this right?
+              otherPath: "Swap",
+            }
+          },
+          {
+            beats: turnBeats,
+            endPosition: {
+              ...startingPos,
+              // TODO Does CourtesyTurn always end in same position?
+              which: startPos.which,
+              facing: startPos.which.facingAcross(),
+            },
+            movementPattern: {
+              kind: SemanticAnimationKind.CourtesyTurn,
+              clockwise: cwCourtesyTurn,
+            }
+          }
+        ], startingPos);
+      }
+    });
+  }
+}
+
+class Chain extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new ChainSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, Chain);

www/js/moves/circle.ts

@@ -0,0 +1,38 @@
+import { Facing, handsInCircle } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "circle";
+
+class CircleSingleVariant extends SingleVariantMoveInterpreter<Circle, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    return this.handleCircleMove(({ startPos }) => {
+      const places = this.move.parameters.places / 90 * (this.move.parameters.turn ? 1 : -1);
+
+      return this.combine([
+        {
+          beats: this.move.beats,
+          endPosition: {
+            ...startPos,
+            facing: Facing.CenterOfCircle,
+            hands: handsInCircle,
+            which: startPos.which.circleLeft(places),
+          },
+          movementPattern: {
+            kind: SemanticAnimationKind.Circle,
+            places,
+          }
+        },
+      ], { ...startPos, facing: Facing.CenterOfCircle });
+    });
+  }
+}
+
+class Circle extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new CircleSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, Circle);

www/js/moves/custom.ts

@@ -0,0 +1,38 @@
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+class CustomSingleVariant extends SingleVariantMoveInterpreter<Custom, "custom"> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    // TODO refactor so this is in separate classes?
+    if (this.move.parameters.custom.includes("mirrored mad robin")) {
+      return this.handleCircleMove(({ id, startPos }) => {
+        // TODO Read custom to decide direction?
+        const startAndEndPos = {
+          ...startPos,
+          facing: startPos.which.facingAcross(),
+          hands: undefined,
+        };
+        return this.combine([{
+          beats: this.move.beats,
+          startPosition: startAndEndPos,
+          endPosition: startAndEndPos,
+          movementPattern: {
+            kind: SemanticAnimationKind.DoSiDo,
+            amount: startPos.which.isLeft() ? -360 : 360,
+            around: startPos.which.leftRightSide(),
+          },
+        }]);
+      });
+    } else {
+      return this.errorStandStill();
+    }
+  }
+}
+
+class Custom extends MoveInterpreter<"custom"> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new CustomSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set("custom", Custom);

www/js/moves/doSiDo.ts

@@ -0,0 +1,80 @@
+import { SemanticPosition, Facing, CircleSide, PositionKind } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "do si do";
+
+class DoSiDoSingleVariant extends SingleVariantMoveInterpreter<DoSiDo, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    if (!this.move.parameters.shoulder) {
+      throw new Error("do si do by left shoulder is unsupported.");
+    }
+
+    let doSiDoEndKind: "Start" | "Swap" | "ShortLinesLeft" | "ShortLinesRight";
+    const doSiDoCircling = this.move.parameters.circling % 360;
+    if (doSiDoCircling === 0) {
+      doSiDoEndKind = "Start";
+    } else if (doSiDoCircling === 180) {
+      doSiDoEndKind = "Swap";
+    } else if (doSiDoCircling === 90) {
+      doSiDoEndKind = this.move.parameters.shoulder ? "ShortLinesLeft" : "ShortLinesRight";
+    } else if (doSiDoCircling === 270) {
+      doSiDoEndKind = this.move.parameters.shoulder ? "ShortLinesRight" : "ShortLinesLeft";
+    } else {
+      throw new Error("do si do by " + this.move.parameters.circling + " degrees is unsupported.");
+    }
+
+    return this.handleCirclePairedMove(this.move.parameters.who, ({ startPos, around, withPos }) => {
+      // TODO Use other parameters?
+      const startingPos: SemanticPosition = {
+        ...startPos,
+        hands: undefined,
+        facing: around === "Center"
+          ? Facing.CenterOfCircle
+          : around === CircleSide.Left || around === CircleSide.Right
+            ? startPos.which.facingUpOrDown()
+            : startPos.which.facingAcross(),
+      };
+
+      let endPos: SemanticPosition;
+      switch (doSiDoEndKind) {
+        case "Start":
+          endPos = startingPos;
+          break;
+        case "Swap":
+          endPos = { ...withPos, facing: startingPos.facing };
+          break;
+        case "ShortLinesLeft":
+        case "ShortLinesRight":
+          endPos = {
+            kind: PositionKind.ShortLines,
+            which: startPos.which.toShortLines(doSiDoEndKind === "ShortLinesLeft" ? Hand.Left : Hand.Right),
+            facing: startingPos.facing,
+            setOffset: startingPos.setOffset,
+            lineOffset: startingPos.lineOffset,
+          }
+      }
+
+      return this.combine([{
+        beats: this.move.beats,
+        startPosition: startingPos,
+        endPosition: endPos,
+        movementPattern: {
+          kind: SemanticAnimationKind.DoSiDo,
+          amount: this.move.parameters.circling,
+          around,
+        },
+      }]);
+    });
+  }
+}
+
+class DoSiDo extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new DoSiDoSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, DoSiDo);

www/js/moves/downTheHall.ts

@@ -0,0 +1,93 @@
+import { Facing, ShortLinesPosition, PositionKind, CirclePosition, SemanticPosition, HandConnection, HandTo, oppositeFacing } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "down the hall";
+
+class DownTheHallSingleVariant extends SingleVariantMoveInterpreter<DownTheHall, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    if (this.move.parameters.who !== "everyone") {
+      throw new Error("Don't know what it means for not everyone to go down the hall.");
+    }
+    if (this.move.parameters.moving !== "all") {
+      throw new Error("Not sure what it means for not all to be moving in down the hall.");
+    }
+    if (this.move.parameters.ender !== "turn-alone" && this.move.parameters.ender !== "turn-couple") {
+      throw new Error("Unsupported down the hall ender: " + this.move.parameters.ender);
+    }
+    if (this.move.parameters.facing === "forward then backward") {
+      throw new Error("Not sure what " + this.move.parameters.facing + " means for down the hall.");
+    }
+    return this.handleMove(({ startPos }) => {
+      const startFacing = this.move.parameters.facing === "backward" ? Facing.Up : Facing.Down;
+      const startWhich: ShortLinesPosition = startPos.kind === PositionKind.ShortLines
+        ? startPos.which
+        // TODO Is this always the right way to convert circle to short lines?
+        //      (Does it even matter except for dance starting formations?)
+        : new Map<CirclePosition, ShortLinesPosition>([
+          [CirclePosition.TopLeft, ShortLinesPosition.FarLeft],
+          [CirclePosition.BottomLeft, ShortLinesPosition.MiddleLeft],
+          [CirclePosition.BottomRight, ShortLinesPosition.MiddleRight],
+          [CirclePosition.TopRight, ShortLinesPosition.FarRight],
+        ]).get(startPos.which)!;
+      const startingPos: SemanticPosition & { kind: PositionKind.ShortLines, setOffset: number } = {
+        kind: PositionKind.ShortLines,
+        facing: startFacing,
+        which: startWhich,
+        hands: startWhich.isMiddle() ? new Map<Hand, HandConnection>([
+          [Hand.Left, { hand: Hand.Left, to: HandTo.DancerLeft }],
+          [Hand.Right, { hand: Hand.Right, to: HandTo.DancerRight }],
+        ]) : new Map<Hand, HandConnection>([
+          startWhich.isLeft() === (this.move.parameters.facing === "backward")
+            ? [Hand.Left, { hand: Hand.Left, to: HandTo.DancerLeft }]
+            : [Hand.Right, { hand: Hand.Right, to: HandTo.DancerRight }]
+        ]),
+        setOffset: startPos.setOffset ?? 0,
+        lineOffset: startPos.lineOffset,
+      };
+
+      return this.combine([
+        {
+          beats: 4,
+          endPosition: {
+            ...startingPos,
+            setOffset: startingPos.setOffset + 1
+          },
+          movementPattern: { kind: SemanticAnimationKind.Linear },
+        },
+        {
+          beats: this.move.beats - 4,
+          endPosition: {
+            ...startingPos,
+            setOffset: startingPos.setOffset + 1,
+            facing: oppositeFacing(startFacing),
+            which: this.move.parameters.ender === "turn-alone" ? startWhich : startWhich.swapOnSide(),
+          },
+          movementPattern: this.move.parameters.ender === "turn-couple"
+            ? {
+              kind: SemanticAnimationKind.TwirlSwap,
+              around: startWhich.leftRightSide(),
+              // !== is NXOR, each of these booleans being flipped flips which hand to use.
+              hand: startWhich.isMiddle() !== (startWhich.isLeft() !== (this.move.parameters.facing === "forward"))
+                ? Hand.Left
+                : Hand.Right
+            }
+            : {
+              kind: SemanticAnimationKind.Linear,
+              minRotation: startWhich.isMiddle() === startWhich.isLeft() ? -180 : +180,
+            },
+        },
+      ], startingPos);
+    });
+  }
+}
+
+class DownTheHall extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new DownTheHallSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, DownTheHall);

www/js/moves/formAnOceanWave.ts

@@ -0,0 +1,131 @@
+import { SemanticPosition, BalanceWeight, ShortLinesPosition, Facing, PositionKind, handsInShortLine, handsInLine } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, PartialLowLevelMove, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "form an ocean wave";
+
+class FormAnOceanWaveSingleVariant extends SingleVariantMoveInterpreter<FormAnOceanWave, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    if (this.move.parameters.dir !== "across") {
+      throw new Error("Diagonal ocean waves are unsupported.");
+    }
+    const centerHand = this.move.parameters["c.hand"] ? Hand.Right : Hand.Left;
+    if (this.move.parameters["pass thru"]) {
+      return this.handleCircleMove(({ id, startPos }) => {
+        const balBeats = this.move.parameters.bal ? this.move.beats / 2 : 0;
+        const balPartBeats = balBeats / 2;
+        // TODO balance direction?
+        const balance: ((prevEnd: SemanticPosition) => PartialLowLevelMove)[] = this.move.parameters.bal ? [
+          prevEnd => ({
+            beats: balPartBeats,
+            endPosition: { ...prevEnd, balance: BalanceWeight.Forward },
+            movementPattern: { kind: SemanticAnimationKind.Linear },
+          }),
+          prevEnd => ({
+            beats: balPartBeats,
+            endPosition: { ...prevEnd, balance: BalanceWeight.Backward },
+            movementPattern: { kind: SemanticAnimationKind.Linear },
+          }),
+        ] : [];
+
+        const isCenter = this.findPairOpposite(this.move.parameters.center, id) !== null;
+        const which = startPos.which.isLeft()
+          ? isCenter
+            ? ShortLinesPosition.MiddleRight
+            : ShortLinesPosition.FarRight
+          : isCenter
+            ? ShortLinesPosition.MiddleLeft
+            : ShortLinesPosition.FarLeft;
+        // TODO Not sure this facing computation is right.
+        const facing = (centerHand === Hand.Left) !== isCenter !== which.isLeft() ? Facing.Up : Facing.Down;
+        return this.combine([{
+          beats: this.move.beats - balBeats,
+          endPosition: {
+            kind: PositionKind.ShortLines,
+            which,
+            facing,
+            hands: handsInShortLine({ which, facing, wavy: true }),
+            setOffset: startPos.setOffset,
+            lineOffset: startPos.lineOffset,
+          },
+          movementPattern: which.isMiddle()
+            ? { kind: SemanticAnimationKind.Linear }
+            : {
+              kind: SemanticAnimationKind.RotateAround,
+              around: "Center",
+              minAmount: centerHand === Hand.Left ? 1 : -1,
+              close: false,
+              byHand: undefined,
+            },
+        }, ...balance], startPos);
+      });
+    } else {
+
+      return this.handleMove(({ id, startPos }) => {
+        const isCenter = this.findPairOpposite(this.move.parameters.center, id) !== null;
+
+        const which = startPos.which.isLeft()
+          ? (isCenter ? ShortLinesPosition.MiddleLeft : ShortLinesPosition.FarLeft)
+          : (isCenter ? ShortLinesPosition.MiddleRight : ShortLinesPosition.FarRight);
+        const facing = (centerHand === Hand.Right) === (which === ShortLinesPosition.MiddleLeft || which === ShortLinesPosition.FarRight) ? Facing.Down : Facing.Up;
+
+        const linePos: SemanticPosition = {
+          kind: PositionKind.ShortLines,
+          which,
+          facing,
+          hands: handsInLine({ wavy: true, which, facing }),
+          setOffset: startPos.setOffset,
+          lineOffset: startPos.lineOffset,
+        };
+
+        if (this.move.parameters.bal) {
+          // TODO Is balance weight always forward/backward here?
+          const balanceBeats = Math.min(this.move.beats, 4);
+          const transitionBeats = this.move.beats - balanceBeats;
+          const balanceForwardBeats = balanceBeats / 2;
+          const balanceBackwardBeats = balanceBeats - balanceForwardBeats;
+
+          const balance: [PartialLowLevelMove, PartialLowLevelMove] = [
+            {
+              beats: balanceForwardBeats,
+              endPosition: { ...linePos, balance: BalanceWeight.Forward },
+              movementPattern: { kind: SemanticAnimationKind.Linear },
+            },
+            {
+              beats: balanceBackwardBeats,
+              endPosition: { ...linePos, balance: BalanceWeight.Backward },
+              movementPattern: { kind: SemanticAnimationKind.Linear },
+            },
+          ];
+          if (transitionBeats === 0) {
+            // No transition, just balance.
+            return this.combine(balance, linePos);
+          } else {
+            return this.combine([{
+              beats: transitionBeats,
+              endPosition: linePos,
+              movementPattern: { kind: SemanticAnimationKind.Linear },
+            },
+            ...balance], startPos);
+          }
+        } else {
+          return this.combine([{
+            beats: this.move.beats,
+            endPosition: linePos,
+            movementPattern: { kind: SemanticAnimationKind.Linear },
+          }], startPos);
+        }
+      });
+    }
+  }
+}
+
+class FormAnOceanWave extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new FormAnOceanWaveSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, FormAnOceanWave);

www/js/moves/formLongWaves.ts

@@ -0,0 +1,42 @@
+import { SemanticPosition, PositionKind, handsInLine } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "form long waves";
+
+class FormLongWavesSingleVariant extends SingleVariantMoveInterpreter<FormLongWaves, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    // TODO A zero beat move should just be selecting a variant? Or maybe not because this just changes facing/hands.
+    if (this.move.beats !== 0) {
+      throw new Error(this.move.move + " unsupported except for zero beats marking end of previous move.");
+    }
+    return this.handleCircleMove(({ id, startPos }) => {
+      const facingIn = this.findPairOpposite(this.move.parameters.who, id) !== null;
+
+      const startAndEndPos: SemanticPosition = {
+        kind: PositionKind.Circle,
+        which: startPos.which,
+        facing: facingIn ? startPos.which.facingAcross() : startPos.which.facingOut(),
+        hands: handsInLine({ wavy: true, which: startPos.which }),
+        setOffset: startPos.setOffset,
+        lineOffset: startPos.lineOffset,
+      }
+
+      return this.combine([{
+        beats: this.move.beats,
+        endPosition: startAndEndPos,
+        movementPattern: { kind: SemanticAnimationKind.StandStill },
+      }
+      ], startAndEndPos);
+    });
+  }
+}
+
+class FormLongWaves extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new FormLongWavesSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, FormLongWaves);

www/js/moves/giveTake.ts

@@ -0,0 +1,56 @@
+import { LongLines, HandConnection, HandTo } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, PartialLowLevelMove, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "give & take";
+
+class GiveTakeSingleVariant extends SingleVariantMoveInterpreter<GiveTake, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    const give: boolean = this.move.parameters.give;
+    const takeToSide = this.move.parameters.who;
+
+    const giveBeats = give ? this.move.beats / 2 : 0;
+    const takeBeats = this.move.beats - giveBeats;
+
+    return this.handleCircleMove(({ id, startPos }) => {
+      const isTaker = this.findPairOpposite(takeToSide, id) !== null;
+
+      const maybeGive: [] | [PartialLowLevelMove] = give ? [{
+        beats: giveBeats,
+        endPosition: { ...startPos, longLines: LongLines.Forward },
+        movementPattern: { kind: SemanticAnimationKind.Linear, minRotation: 0 },
+      }] : [];
+      const takeHands = new Map<Hand, HandConnection>([
+        [Hand.Left, { hand: Hand.Right, to: HandTo.DancerForward }],
+        [Hand.Right, { hand: Hand.Left, to: HandTo.DancerForward }],
+      ]);
+
+      return this.combine([...maybeGive, (prevEnd) => ({
+        beats: takeBeats,
+        startPosition: { ...prevEnd, hands: undefined },
+        endPosition: isTaker ? {
+          ...startPos,
+          which: startPos.which,
+          longLines: undefined,
+          hands: takeHands,
+        } : {
+          ...startPos,
+          which: startPos.which.swapAcross(),
+          longLines: LongLines.Near,
+          hands: takeHands,
+        },
+        movementPattern: { kind: SemanticAnimationKind.Linear, minRotation: 0 },
+      })], startPos);
+    });
+  }
+}
+
+class GiveTake extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new GiveTakeSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, GiveTake);

www/js/moves/hey.ts

@@ -0,0 +1,339 @@
+import { DancerIdentity } from "../danceCommon.js";
+import { SemanticPosition, PositionKind, ShortLinesPosition, CirclePosition, CircleSide, Facing } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { LowLevelMove, SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, PartialLowLevelMove, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+import { dancerIsPair } from "../libfigure/util.js";
+
+const moveName: Move["move"] = "hey";
+
+class HeySingleVariant extends SingleVariantMoveInterpreter<Hey, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    // Needed for inner functions... that probably should be methods.
+    const move = this.move;
+
+    type HeyStep = {
+      kind: "StandStill" | "Loop" | "CenterPass" | "EndsPassIn" | "EndsPassOut" | "Ricochet",
+      endPosition: SemanticPosition,
+    }
+
+    if (this.move.parameters.dir !== "across") {
+      throw new Error("Unsupported hey direction: " + this.move.parameters.dir);
+    }
+
+    let heyParts: number;
+    switch (this.move.parameters.until) {
+      case "half":
+        heyParts = 4;
+        break;
+      case "full":
+        heyParts = 8;
+        break;
+      default:
+        throw new Error("Unsupported hey 'until': " + this.move.parameters.until);
+    }
+    const heyPartBeats: number = this.move.beats / heyParts;
+    // TODO is this right?
+    const firstPassInCenter: boolean = dancerIsPair(this.move.parameters.who);
+    const centerShoulder = firstPassInCenter === this.move.parameters.shoulder ? Hand.Right : Hand.Left;
+    const endsShoulder = centerShoulder.opposite();
+
+    function fixupHeyOtherPath(withoutOtherPath: Map<DancerIdentity, (LowLevelMove & { heyStep?: HeyStep })[]>): Map<DancerIdentity, LowLevelMove[]> {
+      const numSteps = withoutOtherPath.get(DancerIdentity.OnesLark)!.length;
+      for (let i = 0; i < numSteps; i++) {
+        for (const id of withoutOtherPath.keys()) {
+          const lowLevelMove = withoutOtherPath.get(id)![i];
+          if (lowLevelMove.movementPattern.kind !== SemanticAnimationKind.PassBy
+            || !lowLevelMove.heyStep
+            || lowLevelMove.movementPattern.otherPath) {
+            continue;
+          }
+
+          const heyStepKind = lowLevelMove.heyStep.kind;
+          let foundPair = false;
+          for (const otherId of withoutOtherPath.keys()) {
+            const otherLowLevelMove = withoutOtherPath.get(otherId)![i];
+            if (id === otherId
+              || otherLowLevelMove.movementPattern.kind !== SemanticAnimationKind.PassBy
+              || !otherLowLevelMove.heyStep
+              || otherLowLevelMove.movementPattern.otherPath) {
+              continue;
+            }
+
+            const otherHeyStepKind = otherLowLevelMove.heyStep.kind;
+
+            if (heyStepKind === "CenterPass" && otherHeyStepKind === "CenterPass"
+              || (lowLevelMove.startPosition.which.leftRightSide() === otherLowLevelMove.startPosition.which.leftRightSide()
+                && (heyStepKind === "EndsPassIn" && otherHeyStepKind === "EndsPassOut"
+                  || heyStepKind === "EndsPassOut" && otherHeyStepKind === "EndsPassIn"))) {
+              lowLevelMove.movementPattern.otherPath = {
+                start: { ...otherLowLevelMove.startPosition, setOffset: lowLevelMove.startPosition.setOffset, lineOffset: lowLevelMove.startPosition.lineOffset },
+                end: { ...otherLowLevelMove.endPosition, setOffset: lowLevelMove.endPosition.setOffset, lineOffset: lowLevelMove.endPosition.lineOffset },
+              }
+              otherLowLevelMove.movementPattern.otherPath = {
+                start: { ...lowLevelMove.startPosition, setOffset: otherLowLevelMove.startPosition.setOffset, lineOffset: otherLowLevelMove.startPosition.lineOffset },
+                end: { ...lowLevelMove.endPosition, setOffset: otherLowLevelMove.endPosition.setOffset, lineOffset: otherLowLevelMove.endPosition.lineOffset },
+              }
+              foundPair = true;
+              break;
+            }
+          }
+
+          if (!foundPair && heyStepKind === "EndsPassOut") {
+            // Then other is standing still.
+            const pos = {
+              ...([...withoutOtherPath.values()]
+                .map(otherMoves => otherMoves[i])
+                .filter(m => m.movementPattern.kind === SemanticAnimationKind.StandStill
+                  && m.endPosition.which.leftRightSide() === lowLevelMove.endPosition.which.leftRightSide())
+              [0].endPosition),
+              setOffset: lowLevelMove.startPosition.setOffset, lineOffset: lowLevelMove.startPosition.lineOffset
+            }
+            lowLevelMove.movementPattern.otherPath = { start: pos, end: pos };
+          }
+        }
+
+        for (const id of withoutOtherPath.keys()) {
+          const lowLevelMove = withoutOtherPath.get(id)![i];
+          if (lowLevelMove.movementPattern.kind === SemanticAnimationKind.PassBy
+            && !lowLevelMove.movementPattern.otherPath) {
+            throw new Error("Failed to fill in otherPath for " + id + " on hey step " + i);
+          }
+        }
+      }
+
+      // Object was mutated.
+      return withoutOtherPath;
+    }
+
+    return fixupHeyOtherPath(this.handleMove(({ id, startPos }) => {
+      const endsInCircle = startPos.kind === PositionKind.Circle;
+      function heyStepToPartialLowLevelMove(heyStep: HeyStep): PartialLowLevelMove & { heyStep: HeyStep } {
+        return {
+          beats: heyPartBeats,
+          // TODO use circle positions on ends? ... unless hey ends in a box the gnat or similar...
+          endPosition: heyStep.endPosition,
+          movementPattern: heyStep.kind === "StandStill" ? {
+            kind: SemanticAnimationKind.StandStill,
+          } : heyStep.kind === "Loop" ? {
+            // TODO Loop should probably be its own kind? Or RotateAround?
+            kind: SemanticAnimationKind.Linear,
+            minRotation: endsShoulder === Hand.Right ? +180 : -180,
+          } : heyStep.kind === "Ricochet" ? {
+            // TODO This is a hack.
+            kind: SemanticAnimationKind.PassBy,
+            around: heyStep.endPosition.which.leftRightSide(),
+            withHands: false,
+            otherPath: "Swap",
+            facing: "Start",
+            side: endsShoulder,
+          } : {
+            kind: SemanticAnimationKind.PassBy,
+            around: heyStep.kind === "CenterPass" ? "Center" : heyStep.endPosition.which.leftRightSide(),
+            withHands: false,
+            side: heyStep.kind === "CenterPass" ? centerShoulder : endsShoulder,
+            facing: "Start",
+            otherPath: undefined!, // Placeholder, fixup later.
+          },
+          heyStep,
+        };
+      }
+      function continueHey(prevStep: HeyStep, stepsLeft: number, beenInCenter: boolean): HeyStep {
+        // TODO Not sure why type checker requires rechecking this here.
+        if (move.move !== "hey") throw new Error("Unreachable.");
+
+        // Continuing hey so everyone is either passing (in center or on ends) or looping on ends.
+        if (prevStep.endPosition.kind === PositionKind.Circle) {
+          if (prevStep.endPosition.facing === prevStep.endPosition.which.facingAcross()) {
+            if (stepsLeft === 0) {
+              return {
+                kind: "StandStill",
+                endPosition: prevStep.endPosition,
+              }
+            }
+            return {
+              kind: "EndsPassIn",
+              endPosition: {
+                kind: PositionKind.ShortLines,
+                which: prevStep.endPosition.which.isLeft() ? ShortLinesPosition.MiddleLeft : ShortLinesPosition.MiddleRight,
+                facing: prevStep.endPosition.which.facingAcross(),
+                setOffset: prevStep.endPosition.setOffset,
+                lineOffset: prevStep.endPosition.lineOffset,
+              },
+            }
+          }
+          else {
+            if (stepsLeft === 1 && !endsInCircle) {
+              return {
+                kind: "Loop",
+                endPosition: {
+                  kind: PositionKind.ShortLines,
+                  which: prevStep.endPosition.which.isLeft() ? ShortLinesPosition.FarLeft : ShortLinesPosition.FarRight,
+                  facing: prevStep.endPosition.which.facingAcross(),
+                  setOffset: prevStep.endPosition.setOffset,
+                  lineOffset: prevStep.endPosition.lineOffset,
+                },
+              }
+            }
+            return {
+              kind: "Loop",
+              endPosition: {
+                ...prevStep.endPosition,
+                which: prevStep.endPosition.which.swapUpAndDown(),
+                facing: prevStep.endPosition.which.facingAcross()
+              },
+            }
+          }
+        }
+        else if (prevStep.endPosition.kind === PositionKind.ShortLines) {
+          const isFacingSide = prevStep.endPosition.facing === prevStep.endPosition.which.facingSide();
+          const inMiddle = prevStep.endPosition.which.isMiddle();
+          if (!inMiddle && !isFacingSide) {
+            return {
+              kind: "Loop",
+              endPosition: { ...prevStep.endPosition, facing: prevStep.endPosition.which.facingSide() },
+            }
+          } else if (inMiddle && isFacingSide) {
+            return {
+              kind: "EndsPassOut",
+              endPosition: {
+                ...prevStep.endPosition,
+                kind: PositionKind.Circle,
+                which: prevStep.endPosition.which.isLeft()
+                  ? (endsShoulder === Hand.Right ? CirclePosition.TopLeft : CirclePosition.BottomLeft)
+                  : (endsShoulder === Hand.Right ? CirclePosition.BottomRight : CirclePosition.TopRight),
+              },
+            }
+          }
+          else if (!isFacingSide) {
+            const rico = inCenterFirst
+              ? beenInCenter
+                ? move.parameters.rico3
+                : move.parameters.rico1
+              : beenInCenter
+                ? move.parameters.rico4
+                : move.parameters.rico2;
+
+            if (rico) {
+              const onLeftSide = prevStep.endPosition.which.isLeft();
+              return {
+                kind: "Ricochet",
+                endPosition: {
+                  ...prevStep.endPosition,
+                  kind: PositionKind.Circle,
+                  which: CirclePosition.fromSides(prevStep.endPosition.which.leftRightSide(),
+                    // TODO might be swapped
+                    (endsShoulder === Hand.Left) === onLeftSide ? CircleSide.Top : CircleSide.Bottom),
+                  facing: onLeftSide ? Facing.Left : Facing.Right,
+                }
+              }
+            } else {
+              return {
+                kind: "CenterPass",
+                endPosition: {
+                  ...prevStep.endPosition,
+                  which: prevStep.endPosition.which.swapSides()
+                },
+              }
+            }
+          }
+          else {
+            return {
+              kind: inMiddle ? "EndsPassOut" : "EndsPassIn",
+              endPosition: {
+                ...prevStep.endPosition,
+                which: prevStep.endPosition.which.swapOnSide()
+              },
+            }
+          }
+        } else {
+          throw new Error("Unexpected PositionKind: " + (<any>prevStep.endPosition).kind);
+        }
+      }
+
+      const inCenterFirst = firstPassInCenter && this.findPairOpposite(this.move.parameters.who, id) !== null
+        || this.move.parameters.who2 && this.findPairOpposite(this.move.parameters.who2, id) !== null;
+
+      let firstHeyStep: HeyStep;
+      let startingPos: SemanticPosition;
+      if (firstPassInCenter) {
+        if (startPos.kind !== PositionKind.Circle) {
+          throw new Error("Hey starting in center not from circle is unsupported.");
+        }
+        startingPos = {
+          kind: startPos.kind,
+          which: startPos.which,
+          facing: startPos.which.isLeft() ? Facing.Right : Facing.Left,
+          setOffset: startPos.setOffset,
+          lineOffset: startPos.lineOffset,
+        };
+        if (inCenterFirst) {
+          if (this.move.parameters.rico1) {
+            firstHeyStep = {
+              kind: "Ricochet",
+              endPosition: {
+                kind: PositionKind.Circle,
+                which: startPos.which.swapUpAndDown(),
+                facing: startPos.which.facingOut(),
+                setOffset: startPos.setOffset,
+                lineOffset: startPos.lineOffset,
+              }
+            };
+          } else {
+            firstHeyStep = {
+              kind: "CenterPass",
+              endPosition: {
+                kind: PositionKind.ShortLines,
+                which: startPos.which.isLeft() ? ShortLinesPosition.MiddleRight : ShortLinesPosition.MiddleLeft,
+                facing: startingPos.facing,
+                setOffset: startPos.setOffset,
+                lineOffset: startPos.lineOffset,
+              }
+            };
+          }
+        } else {
+          firstHeyStep = {
+            kind: "StandStill",
+            endPosition: startingPos,
+          }
+        }
+      } else {
+        if (startPos.kind !== PositionKind.ShortLines) {
+          throw new Error("Hey with first pass on ends must start approximately in short lines.");
+        }
+
+        const startFacing = startPos.which.facingSide();
+        startingPos = {
+          kind: startPos.kind,
+          which: startPos.which,
+          facing: startFacing,
+          setOffset: startPos.setOffset,
+          lineOffset: startPos.lineOffset,
+        };
+        firstHeyStep = {
+          kind: startingPos.which.isMiddle() ? "EndsPassOut" : "EndsPassIn",
+          endPosition: { ...startingPos, which: startPos.which.swapOnSide() },
+        }
+      }
+
+      const heySteps: HeyStep[] = [firstHeyStep];
+      let beenInCenter = firstHeyStep.kind === "CenterPass" || firstHeyStep.kind === "Ricochet";
+      for (let i = 1; i < heyParts; i++) {
+        const isLast = i === heyParts - 1;
+        const nextHeyStep = continueHey(heySteps[i - 1], heyParts - i - 1, beenInCenter);
+        beenInCenter ||= nextHeyStep.kind === "CenterPass" || nextHeyStep.kind === "Ricochet";
+        heySteps.push(nextHeyStep);
+      }
+      return this.combine(heySteps.map(heyStepToPartialLowLevelMove), { ...startingPos, hands: undefined });
+    }));
+  }
+}
+
+class Hey extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new HeySingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, Hey);

www/js/moves/longLines.ts

@@ -0,0 +1,55 @@
+import { SemanticPosition, Facing, HandConnection, HandTo, LongLines } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "long lines";
+
+class LongLinesSingleVariant extends SingleVariantMoveInterpreter<LongLinesInterpreter, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    return this.handleCircleMove(({ startPos }) => {
+      const startPosition: SemanticPosition = {
+        ...startPos,
+        longLines: undefined,
+        // TODO Occassionally dances have long lines facing out. This will get that wrong.
+        facing: startPos.which.isLeft() ? Facing.Right : Facing.Left,
+        hands: new Map<Hand, HandConnection>([
+          [Hand.Left, { hand: Hand.Right, to: HandTo.DancerLeft }],
+          [Hand.Right, { hand: Hand.Left, to: HandTo.DancerRight }],
+        ]),
+      };
+
+      if (this.move.parameters.go) {
+        const forwardBeats = this.move.beats / 2;
+        const backwardBeats = this.move.beats - forwardBeats;
+        return this.combine([
+          {
+            beats: forwardBeats,
+            endPosition: { ...startPosition, longLines: LongLines.Forward },
+            movementPattern: { kind: SemanticAnimationKind.Linear },
+          },
+          {
+            beats: backwardBeats,
+            endPosition: startPosition,
+            movementPattern: { kind: SemanticAnimationKind.Linear, minRotation: 0 },
+          },
+        ], startPosition);
+      } else {
+        return this.combine([{
+          beats: this.move.beats,
+          endPosition: { ...startPosition, longLines: LongLines.Forward },
+          movementPattern: { kind: SemanticAnimationKind.Linear },
+        }], startPosition);
+      }
+    });
+  }
+}
+
+class LongLinesInterpreter extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new LongLinesSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, LongLinesInterpreter);

www/js/moves/madRobin.ts

@@ -0,0 +1,46 @@
+import { SemanticPosition, PositionKind } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "mad robin";
+
+class MadRobinSingleVariant extends SingleVariantMoveInterpreter<MadRobin, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    if (this.move.parameters.circling !== 360) {
+      throw new Error("mad robin circling not exactly once is unsupported.");
+    }
+
+    return this.handleCircleMove(({ id, startPos }) => {
+      // Read who of mad robin to decide direction.
+      const madRobinClockwise: boolean = (this.findPairOpposite(this.move.parameters.who, id) !== null) === startPos.which.isOnLeftLookingAcross();
+
+      const startAndEndPos: SemanticPosition = {
+        kind: PositionKind.Circle,
+        which: startPos.which,
+        facing: startPos.which.facingAcross(),
+        setOffset: startPos.setOffset,
+        lineOffset: startPos.lineOffset,
+      }
+
+      return this.combine([{
+        beats: this.move.beats,
+        startPosition: startAndEndPos,
+        endPosition: startAndEndPos,
+        movementPattern: {
+          kind: SemanticAnimationKind.DoSiDo,
+          amount: madRobinClockwise ? this.move.parameters.circling : -this.move.parameters.circling,
+          around: startPos.which.leftRightSide(),
+        },
+      }]);
+    });
+  }
+}
+
+class MadRobin extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new MadRobinSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, MadRobin);

www/js/moves/passBy.ts

@@ -0,0 +1,35 @@
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "pass by";
+
+class PassBySingleVariant extends SingleVariantMoveInterpreter<PassBy, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    const passByShoulder = this.move.parameters.shoulder ? Hand.Left : Hand.Right;
+    return this.handlePairedMove(this.move.parameters.who, ({ startPos, around, withPos }) => {
+      return this.combine([{
+        beats: this.move.beats,
+        // TODO Is pass by always a swap?
+        endPosition: withPos,
+        movementPattern: {
+          kind: SemanticAnimationKind.PassBy,
+          around,
+          facing: "Forward",
+          otherPath: "Swap",
+          side: passByShoulder,
+          withHands: false,
+        }
+      }], startPos);
+    });
+  }
+}
+
+class PassBy extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new PassBySingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, PassBy);

www/js/moves/passThrough.ts

@@ -0,0 +1,122 @@
+import { CoupleRole } from "../danceCommon.js";
+import { Facing, SemanticPosition, PositionKind, CircleSide } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "pass through";
+
+class PassThroughSingleVariant extends SingleVariantMoveInterpreter<PassThrough, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    if (this.move.parameters.dir === "left diagonal" || this.move.parameters.dir === "right diagonal") {
+      // TODO There's logic for this below, but unsure it's right.
+      throw new Error(this.move.move + " with dir of " + this.move.parameters.dir + " is unsupported.");
+    }
+    const alongSet = this.move.parameters.dir === "along";
+    const passShoulder = this.move.parameters.shoulder ? Hand.Right : Hand.Left;
+
+    // Special-case this.
+    if (this.move.note?.includes("2s shooting the 1s down the center") ?? false) {
+      return this.handleCircleMove(({ id, startPos }) => {
+        const facing = id.coupleRole === CoupleRole.Ones ? Facing.Down : Facing.Up;
+        const endPos: SemanticPosition = {
+          kind: PositionKind.ShortLines,
+          which: startPos.which.unfoldToShortLines(CircleSide.Top),
+          facing,
+          setOffset: (startPos.setOffset ?? 0) + (facing === Facing.Up ? -0.5 : +0.5),
+          lineOffset: startPos.lineOffset,
+        };
+
+        return this.combine([{
+          beats: this.move.beats,
+          endPosition: endPos,
+          movementPattern: {
+            kind: SemanticAnimationKind.PassBy,
+            around: startPos.which.leftRightSide(),
+            side: endPos.which.isLeft() ? Hand.Left : Hand.Right,
+            withHands: false,
+            facing: "Forward",
+            otherPath: "Swap",
+          },
+        }], startPos);
+      });
+    }
+
+    return this.handleMove(({ startPos }) => {
+      if (alongSet && startPos.kind === PositionKind.Circle) {
+        const facing = startPos.which.facingUpOrDown();
+        const endPos: SemanticPosition = {
+          kind: PositionKind.Circle,
+          which: startPos.which,
+          facing,
+          setOffset: (startPos.setOffset ?? 0) + (facing === Facing.Up ? -0.5 : +0.5),
+          lineOffset: startPos.lineOffset,
+        };
+
+        return this.combine([{
+          beats: this.move.beats,
+          endPosition: endPos,
+          movementPattern: {
+            kind: SemanticAnimationKind.PassBy,
+            around: startPos.which.leftRightSide(),
+            side: passShoulder,
+            withHands: false,
+            facing: "Start",
+            otherPath: "Swap",
+          },
+        }], startPos);
+      } else if (!alongSet && startPos.kind === PositionKind.Circle) {
+        const facing = startPos.which.facingAcross();
+        const endPos: SemanticPosition = {
+          kind: PositionKind.Circle,
+          which: startPos.which.swapAcross(),
+          facing,
+          setOffset: (startPos.setOffset ?? 0) + (this.move.parameters.dir === "across"
+            ? 0
+            : (this.move.parameters.dir === "left diagonal") === startPos.which.isLeft() ? -1 : +1),
+          lineOffset: startPos.lineOffset,
+        };
+
+        return this.combine([{
+          beats: this.move.beats,
+          endPosition: endPos,
+          movementPattern: {
+            kind: SemanticAnimationKind.PassBy,
+            around: startPos.which.topBottomSide(),
+            side: passShoulder,
+            withHands: false,
+            facing: "Forward",
+            otherPath: "Swap",
+          },
+        }], startPos);
+      } else if (alongSet && startPos.kind === PositionKind.ShortLines) {
+        // TODO This assumes short *wavy* lines.
+
+        const endPos: SemanticPosition = {
+          ...startPos,
+          balance: undefined,
+          // TODO only swap sometimes...
+          which: startPos.which.swapOnSide(),
+          setOffset: (startPos.setOffset ?? 0) + (startPos.facing === Facing.Up ? -0.5 : +0.5),
+        };
+
+        return this.combine([{
+          beats: this.move.beats,
+          endPosition: endPos,
+          movementPattern: { kind: SemanticAnimationKind.Linear },
+        }], startPos);
+      } else {
+        throw new Error(this.move.move + " with dir of " + this.move.parameters.dir + " starting from " + startPos.kind + " is unsupported.");
+      }
+    });
+  }
+}
+
+class PassThrough extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new PassThroughSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, PassThrough);

www/js/moves/petronella.ts

@@ -0,0 +1,59 @@
+import { Facing, SemanticPosition } from "../interpreterCommon.js";
+import { SemanticAnimationKind, LowLevelMove } from "../lowLevelMove.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, PartialLowLevelMove, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+import { balanceCircleInAndOut } from "./balanceTheRing.js";
+
+class PetronellaSingleVariant extends SingleVariantMoveInterpreter<Petronella, "petronella"> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    // TODO These should be actual parameters, not parsing the notes...
+    const rightShoulder: boolean = !(this.move.note?.includes('left') ?? false);
+    const newCircle: boolean = this.move.note?.includes('end facing') ?? this.move.progression;
+
+    return this.handleCircleMove(({ startPos }) => {
+      let finalPosition = {
+        ...startPos,
+        facing: Facing.CenterOfCircle,
+        which: startPos.which.circleRight(rightShoulder ? 1 : -1),
+        hands: undefined,
+      };
+
+      if (newCircle) {
+        finalPosition = {
+          ...finalPosition,
+          which: finalPosition.which.swapUpAndDown(),
+          setOffset: (finalPosition.setOffset ?? 0) + (finalPosition.which.isTop() ? -0.5 : +0.5),
+        }
+      }
+
+      const spin: ((prevEnd: SemanticPosition) => PartialLowLevelMove) = prevEnd => ({
+        beats: this.move.beats - (this.move.parameters.bal ? 4 : 0),
+        startPosition: {
+          ...prevEnd,
+          facing: Facing.CenterOfCircle,
+          hands: undefined,
+        },
+        endPosition: finalPosition,
+        movementPattern: {
+          kind: SemanticAnimationKind.Linear,
+          minRotation: rightShoulder ? 180 : -180,
+          handsDuring: "None",
+        },
+      });
+
+      if (this.move.parameters.bal) {
+        const balance: LowLevelMove[] = balanceCircleInAndOut(this.move, startPos);
+        return PetronellaSingleVariant.append([...balance], spin);
+      } else {
+        return this.combine([spin]);
+      }
+    });
+  }
+}
+
+class Petronella extends MoveInterpreter<"petronella"> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new PetronellaSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set("petronella", Petronella);

www/js/moves/promenade.ts

@@ -0,0 +1,79 @@
+import { DanceRole } from "../danceCommon.js";
+import { HandTo, SemanticPosition, DancerDistance, HandConnection, PositionKind } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, PartialLowLevelMove, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "promenade";
+
+class PromenadeSingleVariant extends SingleVariantMoveInterpreter<Promenade, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    if (this.move.parameters.dir !== "across") {
+      // TODO "along" would be the bicycle chain? Not sure what left/right diagonal means here.
+      throw "Promenade not across the set is unsupported."
+    }
+
+    // TODO How to know?
+    const twirlAfterPromenade = true;
+    const twirlBeats = twirlAfterPromenade ? this.move.beats / 2 : 0;
+    const promenadeBeats = this.move.beats - twirlBeats;
+
+    return this.handleCirclePairedMove(this.move.parameters.who, ({ startPos }) => {
+      const handTo = startPos.which.isOnLeftLookingAcross() ? HandTo.DancerRight : HandTo.DancerLeft;
+      const startingPos: SemanticPosition = {
+        ...startPos,
+        facing: startPos.which.facingAcross(),
+        dancerDistance: DancerDistance.Compact,
+        hands: new Map<Hand, HandConnection>([
+          [Hand.Left, { hand: Hand.Left, to: handTo }],
+          [Hand.Right, { hand: Hand.Right, to: handTo }],
+        ]),
+      };
+
+      const endSetOffset = this.move.progression
+        ? (startPos.setOffset ?? 0) + (startPos.which.isLeft() ? +0.5 : -0.5)
+        : startPos.setOffset;
+      const beforeTwirlPos: SemanticPosition & { kind: PositionKind.Circle } = {
+        ...startingPos,
+        which: startPos.which.swapAcross(),
+        facing: startPos.which.facingAcross(),
+        setOffset: endSetOffset,
+      };
+      const endPos: SemanticPosition = {
+        ...beforeTwirlPos,
+        which: beforeTwirlPos.which.swapUpAndDown(),
+        facing: beforeTwirlPos.which.facingAcross(),
+        dancerDistance: undefined,
+      };
+
+      const maybeTwirl: [] | [PartialLowLevelMove] = (twirlAfterPromenade ? [{
+        beats: twirlBeats,
+        endPosition: endPos,
+        movementPattern: {
+          kind: SemanticAnimationKind.CourtesyTurn,
+          clockwise: this.move.parameters.turn, // TODO or ! this?
+        }
+      }] : [])
+
+      return this.combine([{
+        beats: promenadeBeats,
+        endPosition: beforeTwirlPos,
+        movementPattern: {
+          kind: SemanticAnimationKind.Promenade,
+          swingRole: startPos.which.isOnLeftLookingAcross() ? DanceRole.Lark : DanceRole.Robin,
+          twirl: true,
+          passBy: this.move.parameters.turn ? Hand.Left : Hand.Right,
+        }
+      }, ...maybeTwirl], startingPos);
+    });
+  }
+}
+
+class Promenade extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new PromenadeSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, Promenade);

www/js/moves/pullByDancers.ts

@@ -0,0 +1,83 @@
+import { HandConnection, HandTo, BalanceWeight } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, PartialLowLevelMove, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "pull by dancers";
+
+class PullByDancersSingleVariant extends SingleVariantMoveInterpreter<PullByDancers, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    // TODO Might make sense to think of pull by as not a full swap?
+    //  e.g., in Blue and Green Candles, it's treated as only getting to
+    //        ShortLinesPosition.Middle* before doing an allemande.
+    return this.handlePairedMove(this.move.parameters.who, ({ startPos, around, withPos }) => {
+      const hand = this.move.parameters.hand ? Hand.Right : Hand.Left;
+      const balanceBeats = this.move.parameters.bal
+        ? this.move.beats > 4
+          ? this.move.beats - 4
+          : 2
+        : 0;
+      const balancePartBeats = balanceBeats / 2;
+      const pullBeats = this.move.beats - balanceBeats;
+
+      // TODO Adjust facing?
+      const startPosition = {
+        ...startPos,
+        hands: new Map<Hand, HandConnection>([
+          [
+            hand,
+            { hand, to: around === "Center" ? HandTo.DiagonalAcrossCircle : HandTo.DancerForward }
+          ]])
+      };
+
+      const passBy: PartialLowLevelMove = {
+        beats: pullBeats,
+        endPosition: { ...withPos, facing: startPos.facing },
+        movementPattern: {
+          kind: SemanticAnimationKind.PassBy,
+          around,
+          side: hand,
+          withHands: true,
+          facing: "Start",
+          otherPath: "Swap",
+        }
+      };
+
+      if (this.move.parameters.bal) {
+        return this.combine([
+          {
+            beats: balancePartBeats,
+            endPosition: {
+              ...startPosition,
+              balance: BalanceWeight.Forward,
+            },
+            movementPattern: {
+              kind: SemanticAnimationKind.Linear,
+            }
+          },
+          {
+            beats: balancePartBeats,
+            endPosition: {
+              ...startPosition,
+              balance: BalanceWeight.Backward,
+            },
+            movementPattern: {
+              kind: SemanticAnimationKind.Linear,
+            }
+          },
+          passBy], startPosition);
+      } else {
+        return this.combine([passBy], startPosition);
+      }
+    });
+  }
+}
+
+class PullByDancers extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new PullByDancersSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, PullByDancers);

www/js/moves/revolvingDoor.ts

@@ -0,0 +1,74 @@
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "revolving door";
+
+class RevolvingDoorSingleVariant extends SingleVariantMoveInterpreter<RevolvingDoor, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    const byHand = this.move.parameters.hand ? Hand.Right : Hand.Left;
+    // TODO More parts? Or define an animation kind?
+    const waitBeats = 2;
+    const carryBeats = this.move.beats / 2;
+    const returnBeats = this.move.beats - carryBeats - waitBeats;
+    return this.handleCirclePairedMove(this.move.parameters.whom, ({ id, startPos }) => {
+      const isCarried = this.findPairOpposite(this.move.parameters.who, id) === null;
+      const startingPos = { ...startPos, hands: undefined };
+
+      // TODO animation here needs work.
+      if (isCarried) {
+        const endWhich = startPos.which.swapDiagonal();
+        return this.combine([
+          prevEnd => ({
+            beats: waitBeats,
+            endPosition: prevEnd,
+            movementPattern: { kind: SemanticAnimationKind.StandStill },
+          }),
+          {
+            beats: carryBeats,
+            endPosition: {
+              ...startPos,
+              which: endWhich,
+              facing: endWhich.facingAcross(),
+            },
+            movementPattern: {
+              kind: SemanticAnimationKind.RotateAround,
+              minAmount: byHand === Hand.Right ? 180 : -180,
+              around: "Center",
+              byHand,
+              close: false,
+            },
+          },
+          prevEnd => ({
+            beats: returnBeats,
+            endPosition: prevEnd,
+            movementPattern: { kind: SemanticAnimationKind.StandStill },
+          }),
+        ], startingPos);
+      } else {
+        return this.combine([
+          {
+            beats: this.move.beats,
+            endPosition: startPos,
+            movementPattern: {
+              kind: SemanticAnimationKind.RotateAround,
+              minAmount: byHand === Hand.Right ? 180 : -180,
+              around: "Center",
+              byHand,
+              close: true,
+            },
+          },
+        ], startingPos);
+      }
+    });
+  }
+}
+
+class RevolvingDoor extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new RevolvingDoorSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, RevolvingDoor);

www/js/moves/rightLeftThrough.ts

@@ -0,0 +1,52 @@
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "right left through";
+
+class RightLeftThroughSingleVariant extends SingleVariantMoveInterpreter<RightLeftThrough, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    if (this.move.parameters.dir !== "across") {
+      throw new Error(this.move.move + " with dir " + this.move.parameters.dir + " is unsupported.");
+    }
+
+    return this.handleCircleMove(({ startPos }) => {
+      const startingPos = { ...startPos, facing: startPos.which.facingAcross() };
+      const swappedPos = { ...startingPos, which: startingPos.which.swapAcross() };
+      return this.combine([
+        {
+          beats: this.move.beats / 2,
+          endPosition: swappedPos,
+          movementPattern: {
+            kind: SemanticAnimationKind.PassBy,
+            side: Hand.Right,
+            withHands: true,
+            facing: "Start",
+            around: startingPos.which.topBottomSide(),
+            otherPath: "Swap",
+          },
+        },
+        {
+          beats: this.move.beats / 2,
+          endPosition: {
+            ...startingPos,
+            which: startingPos.which.swapDiagonal(),
+            facing: startingPos.which.facingOut()
+          },
+          movementPattern: {
+            kind: SemanticAnimationKind.CourtesyTurn,
+          },
+        }
+      ], startingPos);
+    });
+  }
+}
+
+class RightLeftThrough extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new RightLeftThroughSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, RightLeftThrough);

www/js/moves/rollAway.ts

@@ -0,0 +1,74 @@
+import { DanceRole, CoupleRole } from "../danceCommon.js";
+import { PositionKind } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "roll away";
+
+class RollAwaySingleVariant extends SingleVariantMoveInterpreter<RollAway, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    // TODO maybe can roll away in short lines?
+    return this.handleCirclePairedMove(this.move.parameters.who, ({ id, startPos, withPos }) => {
+      let isRoller: boolean;
+      switch (this.move.parameters.who) {
+        case "gentlespoons":
+          isRoller = id.danceRole === DanceRole.Lark;
+          break;
+        case "ladles":
+          isRoller = id.danceRole === DanceRole.Robin;
+          break;
+        case "ones":
+          isRoller = id.coupleRole === CoupleRole.Ones;
+          break;
+        case "twos":
+          isRoller = id.coupleRole === CoupleRole.Twos;
+          break;
+        case "first corners":
+        case "second corners":
+          throw "Roll away in contra corners is unsupported.";
+      }
+
+      // TODO This isn't quite right if there's no 1/2 sash?
+      let swapPos = withPos;
+      if (swapPos.kind === PositionKind.Circle && swapPos.longLines) {
+        swapPos = { ...swapPos, longLines: undefined };
+      }
+
+      // TODO animate hands?
+      if (isRoller) {
+        if (this.move.parameters["½sash"]) {
+          // swap positions by sliding
+          return this.combine([{
+            beats: this.move.beats,
+            endPosition: swapPos,
+            movementPattern: { kind: SemanticAnimationKind.Linear },
+          }], startPos);
+        } else {
+          // just stand still
+          return this.combine([{
+            beats: this.move.beats,
+            endPosition: { ...startPos, longLines: undefined },
+            movementPattern: { kind: SemanticAnimationKind.Linear },
+          }], startPos);
+        }
+      } else {
+        // being rolled away, so do a spin
+        return this.combine([{
+          beats: this.move.beats,
+          // TODO Is this the right end position logic?
+          endPosition: this.move.parameters["½sash"] ? swapPos : { ...startPos, which: startPos.which.swapDiagonal() },
+          movementPattern: { kind: SemanticAnimationKind.RollAway },
+        }], startPos);
+      }
+    });
+  }
+}
+
+class RollAway extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new RollAwaySingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, RollAway);

www/js/moves/roryOMore.ts

@@ -0,0 +1,76 @@
+import { PositionKind, SemanticPosition, Facing, BalanceWeight, handsInLine } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, PartialLowLevelMove, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "Rory O'More";
+class RoryOMoreSingleVariant extends SingleVariantMoveInterpreter<RoryOMore, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    if (this.move.parameters.who !== "everyone") {
+      throw new Error(this.move.move + " that doesn't include everyone is unsupported.");
+    }
+
+    // TODO Could be in long or short lines.
+    const roryDir = this.move.parameters.slide ? Hand.Left : Hand.Right;
+    const balBeats = this.move.parameters.bal ? this.move.beats / 2 : 0;
+    const balPartBeats = balBeats / 2;
+    const roryBeats = this.move.beats - balBeats;
+    return this.handleMove(({ startPos }) => {
+      const isShortLines: boolean = startPos.kind === PositionKind.ShortLines;
+
+      const startingPos: SemanticPosition = {
+        ...startPos,
+        hands: handsInLine({ wavy: true, which: startPos.which, facing: startPos.facing })
+      };
+
+      let endPos: SemanticPosition;
+      if (startPos.kind === PositionKind.ShortLines) {
+        if (startPos.facing !== Facing.Up && startPos.facing !== Facing.Down) {
+          throw new Error("To be in wavy lines, must be facing up or down, not " + startPos.facing);
+        }
+        const endWhich = startPos.which.shift(roryDir, startPos.facing);
+        endPos = {
+          ...startPos,
+          which: endWhich,
+          hands: handsInLine({ wavy: true, which: endWhich, facing: startPos.facing })
+        };
+      } else {
+        throw new Error(this.move.move + " is currently only supported in short lines.");
+      }
+
+      const maybeBalance: PartialLowLevelMove[] = (this.move.parameters.bal ? [
+        {
+          beats: balPartBeats,
+          endPosition: { ...startingPos, balance: roryDir === Hand.Left ? BalanceWeight.Left : BalanceWeight.Right },
+          movementPattern: { kind: SemanticAnimationKind.Linear },
+        },
+        {
+          beats: balPartBeats,
+          endPosition: { ...startingPos, balance: roryDir === Hand.Left ? BalanceWeight.Right : BalanceWeight.Left },
+          movementPattern: { kind: SemanticAnimationKind.Linear },
+        },
+      ] : []);
+
+      return this.combine([...maybeBalance,
+      {
+        beats: roryBeats,
+        endPosition: endPos,
+        movementPattern: {
+          kind: SemanticAnimationKind.Linear,
+          minRotation: roryDir === Hand.Right ? +360 : -360,
+          handsDuring: "None",
+        },
+      }
+      ], startingPos);
+    });
+  }
+}
+
+class RoryOMore extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new RoryOMoreSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, RoryOMore);

www/js/moves/slice.ts

@@ -0,0 +1,56 @@
+import { SemanticPosition, PositionKind, handToDancerToSideInCircleFacingAcross, LongLines } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, PartialLowLevelMove, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "slice";
+
+class SliceSingleVariant extends SingleVariantMoveInterpreter<Slice, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    if (this.move.parameters["slice increment"] === "dancer") {
+      // TODO Maybe this only actually gets used to move an entire couple by going diagonal back?
+      throw new Error("Slicing by a single dancer is unsupported.");
+    }
+
+    const sliceLeft = this.move.parameters.slide;
+    const sliceReturns = this.move.parameters["slice return"] !== "none";
+
+    const sliceForwardBeats = sliceReturns ? this.move.beats / 2 : this.move.beats;
+    const sliceBackwardBeats = this.move.beats - sliceForwardBeats;
+
+    return this.handleCircleMove(({ startPos }) => {
+      const startingPos: SemanticPosition & { setOffset: number } = {
+        kind: PositionKind.Circle,
+        which: startPos.which,
+        facing: startPos.which.facingAcross(),
+        hands: handToDancerToSideInCircleFacingAcross(startPos.which),
+        setOffset: startPos.setOffset ?? 0,
+        lineOffset: startPos.lineOffset,
+      };
+      const sliceAmount = startingPos.which.isLeft() === sliceLeft ? +0.5 : -0.5;
+      const forwardOffset = startingPos.setOffset + sliceAmount;
+      const endOffset = this.move.parameters["slice return"] === "diagonal" ? forwardOffset + sliceAmount : forwardOffset;
+
+      const sliceForward: PartialLowLevelMove = {
+        beats: sliceForwardBeats,
+        endPosition: { ...startingPos, setOffset: forwardOffset, longLines: LongLines.Forward },
+        movementPattern: { kind: SemanticAnimationKind.Linear },
+      };
+      const maybeSliceBackward: PartialLowLevelMove[] = sliceReturns ? [{
+        beats: sliceBackwardBeats,
+        endPosition: { ...startingPos, setOffset: endOffset },
+        movementPattern: { kind: SemanticAnimationKind.Linear },
+      }] : [];
+
+      return this.combine([sliceForward, ...maybeSliceBackward], startingPos);
+    });
+  }
+}
+
+class Slice extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new SliceSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, Slice);

www/js/moves/slideAlongSet.ts

@@ -0,0 +1,35 @@
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName : Move["move"] = "slide along set";
+
+class SlideAlongSetSingleVariant extends SingleVariantMoveInterpreter<SlideAlongSet, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+      const slideLeft = this.move.parameters.slide;
+
+      return this.handleCircleMove(({ startPos }) => {
+        const startingPos = {
+          ...startPos,
+          facing: startPos.which.facingAcross(),
+        };
+
+        return this.combine([{
+          beats: this.move.beats,
+          endPosition: {
+            ...startingPos,
+            setOffset: (startingPos.setOffset ?? 0) + (startingPos.which.isLeft() === slideLeft ? +0.5 : -0.5),
+          },
+          movementPattern: { kind: SemanticAnimationKind.Linear },
+        }], startingPos);
+      });
+  }
+}
+
+class SlideAlongSet extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new SlideAlongSetSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, SlideAlongSet);

www/js/moves/star.ts

@@ -0,0 +1,49 @@
+import { StarGrip, Facing } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "star";
+
+class StarSingleVariant extends SingleVariantMoveInterpreter<Star, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    return this.handleCircleMove(({ startPos }) => {
+      const hand = this.move.parameters.hand ? Hand.Right : Hand.Left;
+      const grip = this.move.parameters.grip === "hands across"
+        ? StarGrip.HandsAcross
+        : this.move.parameters.grip === "wrist grip"
+          ? StarGrip.WristGrip
+          : undefined;
+      const facing = hand === Hand.Left ? Facing.LeftInCircle : Facing.RightInCircle;
+
+      const places = this.move.parameters.places / 90 * (hand === Hand.Right ? 1 : -1);
+
+      return this.combine([
+        {
+          beats: this.move.beats,
+          endPosition: {
+            ...startPos,
+            facing,
+            hands: undefined,
+            which: startPos.which.circleLeft(places),
+          },
+          movementPattern: {
+            kind: SemanticAnimationKind.Star,
+            hand,
+            grip,
+            places,
+          }
+        },
+      ], { ...startPos, facing });
+    });
+  }
+}
+
+class Star extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new StarSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, Star);

www/js/moves/starPromenade.ts

@@ -0,0 +1,51 @@
+import { DancerDistance, handToDancerToSideInCircleFacingAcross } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "star promenade";
+
+class StarPromenadeSingleVariant extends SingleVariantMoveInterpreter<StarPromenade, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    const starPromenadeHand = this.move.parameters.hand ? Hand.Right : Hand.Left;
+    const starPromenadeSwap = (this.move.parameters.circling % 360) === 180;
+    if (!starPromenadeSwap && (this.move.parameters.circling % 360 !== 0)) {
+      throw new Error(this.move.move + " circling by not a multiple of 180 degrees is unsupported.");
+    }
+
+    // TODO start promenade hands/show dancers close
+    return this.handleCircleMove(({ id, startPos }) => {
+      const inCenter = this.findPairOpposite(this.move.parameters.who, id) !== null;
+      // TODO Actually, does star promenade end facing out and butterfly whirl swaps?
+      const endWhich = starPromenadeSwap ? startPos.which.swapDiagonal() : startPos.which;
+      const endFacing = endWhich.facingAcross();
+      return this.combine([{
+        beats: this.move.beats,
+        endPosition: {
+          ...startPos,
+          which: endWhich,
+          facing: endFacing,
+          dancerDistance: DancerDistance.Compact,
+          // TODO Perhaps different hands indication for "scooped"?
+          hands: handToDancerToSideInCircleFacingAcross(endWhich),
+        },
+        movementPattern: {
+          kind: SemanticAnimationKind.RotateAround,
+          around: "Center",
+          byHand: inCenter ? starPromenadeHand : undefined,
+          close: inCenter,
+          minAmount: this.move.parameters.hand ? this.move.parameters.circling : -this.move.parameters.circling,
+        }
+      }], startPos);
+    });
+  }
+}
+
+class StarPromenade extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new StarPromenadeSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, StarPromenade);

www/js/moves/swing.ts

@@ -0,0 +1,187 @@
+import { CoupleRole, DanceRole } from "../danceCommon.js";
+import { LongLines, CircleSide, SemanticPosition, CirclePosition, Facing, PositionKind, HandConnection, HandTo, ShortLinesPosition, handsInLine, BalanceWeight, DancerDistance } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, PartialLowLevelMove, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "swing";
+
+class SwingSingleVariant extends SingleVariantMoveInterpreter<Swing, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    // TODO Use variants instead of nextMove
+    const nextMove = this.moveInterpreter.nextMove;
+
+    return this.handlePairedMove(this.move.parameters.who, ({ id, startPos, around, withId, withPos }) => {
+      // TODO swing can start from non-circle positions.
+      // TODO swing end is only in notes / looking at next move.
+
+      // TODO better way to detect swing end?
+      // TODO more structured way to do this than enumerating next moves here?
+      //      maybe instead of nextMove an optional endPosition for fixing up positions?
+      //      ... but then every move would have to handle that...
+      const afterTake = startPos.longLines === LongLines.Near || withPos.longLines === LongLines.Near;
+      const toShortLines = nextMove.move === "down the hall" || nextMove.move === "up the hall";
+      const endFacingAcross = (around === CircleSide.Left || around === CircleSide.Right) && !toShortLines;
+
+      const startWhich = startPos.which;
+      const startPosition: SemanticPosition = {
+        ...startPos,
+        facing: around === CircleSide.Left || CircleSide.Right
+          ? (startWhich instanceof CirclePosition
+            ? afterTake
+              ? startPos.longLines === LongLines.Near ? startWhich.facingOut() : startWhich.facingAcross()
+              : (startWhich.topBottomSide() === CircleSide.Bottom ? Facing.Up : Facing.Down)
+            : startWhich.facingSide())
+          : (startWhich.isLeft() ? Facing.Right : Facing.Left),
+      };
+
+      const swingRole = id.danceRole != withId.setIdentity.danceRole
+        ? id.danceRole
+        // Make some arbitrary choice for same-role swings
+        : id.coupleRole !== withId.setIdentity.coupleRole
+          ? (id.coupleRole === CoupleRole.Ones ? DanceRole.Lark : DanceRole.Robin)
+          : withId.relativeSet !== 0
+            ? (withId.relativeSet > 0 ? DanceRole.Lark : DanceRole.Robin)
+            : withId.relativeLine !== 0
+              ? (withId.relativeLine > 0 ? DanceRole.Lark : DanceRole.Robin)
+              : /* should be unreachable as this means withId is equal to id */ DanceRole.Lark;
+
+      // TODO This assumes swing around right/left, not center or top/bottom.
+      let endPosition: SemanticPosition;
+      if (endFacingAcross) {
+        endPosition = {
+          ...startPos,
+          kind: PositionKind.Circle,
+          which: startWhich instanceof CirclePosition
+            ? (startWhich.isOnLeftLookingAcross() === (swingRole === DanceRole.Lark)
+              ? startWhich
+              : startWhich.swapUpAndDown())
+            : (startWhich.isLeft()
+              ? (swingRole === DanceRole.Lark ? CirclePosition.BottomLeft : CirclePosition.TopLeft)
+              : (swingRole === DanceRole.Lark ? CirclePosition.TopRight : CirclePosition.BottomRight)),
+          facing: startWhich.leftRightSide() === CircleSide.Left ? Facing.Right : Facing.Left,
+          balance: undefined,
+          dancerDistance: undefined,
+          longLines: undefined,
+          hands: new Map<Hand, HandConnection>([swingRole === DanceRole.Lark
+            ? [Hand.Right, { to: HandTo.DancerRight, hand: Hand.Left }]
+            : [Hand.Left, { to: HandTo.DancerLeft, hand: Hand.Right }]]),
+        };
+      } else if (toShortLines) {
+        const endFacing = nextMove.move === "down the hall" !== (nextMove.parameters.facing === "backward")
+          ? Facing.Down
+          : Facing.Up;
+        const endWhich = startWhich.isLeft()
+          ? ((endFacing === Facing.Down) === (swingRole === DanceRole.Lark) ? ShortLinesPosition.FarLeft : ShortLinesPosition.MiddleLeft)
+          : ((endFacing === Facing.Down) === (swingRole === DanceRole.Lark) ? ShortLinesPosition.MiddleRight : ShortLinesPosition.FarRight)
+        endPosition = {
+          ...startPos,
+          kind: PositionKind.ShortLines,
+          which: endWhich,
+          facing: endFacing,
+          balance: undefined,
+          dancerDistance: undefined,
+          longLines: undefined,
+          hands: handsInLine({ wavy: false, which: endWhich, facing: endFacing }),
+        };
+      }
+      else {
+        // TODO Need to figure out the logic of knowing if this should be facing up or down.
+        //  Probably based on knowing Ones vs. Twos? Also then the not-participating-dancers need their
+        //  "standing still" to update that they are in a new set...
+        //throw new Error("Swing to new circle currently unsupported.");
+        endPosition = {
+          // end not facing across or in short lines, so transitioning to new circle like in many contra corners dances.
+          ...startPos,
+        };
+      }
+
+      const swingBeats = this.move.parameters.prefix === "none" ? this.move.beats
+        : this.move.parameters.prefix === "balance"
+          ? this.move.beats > 8 ? 8 : this.move.beats - 4
+          : this.move.parameters.prefix === "meltdown"
+            ? this.move.beats - 4
+            : (() => { throw "Unknown swing prefix: " + this.move.parameters.prefix })();
+
+      const swing: PartialLowLevelMove = {
+        beats: swingBeats,
+        endPosition: endPosition,
+        movementPattern: {
+          kind: SemanticAnimationKind.Swing,
+          minAmount: 360,
+          around,
+          endFacing: startWhich.leftRightSide() === CircleSide.Left ? Facing.Right : Facing.Left,
+          swingRole,
+          afterTake,
+        },
+      };
+
+      switch (this.move.parameters.prefix) {
+        case "none":
+          return this.combine([swing,], startPosition);
+        case "balance":
+          // TODO Right length for balance?
+          const balancePartBeats = this.move.beats > 8 ? (this.move.beats - 8) / 2 : 2;
+          const startWithBalHands = {
+            ...startPosition,
+            hands: new Map<Hand, HandConnection>([
+              [Hand.Left, { to: HandTo.DancerForward, hand: Hand.Right }],
+              [Hand.Right, { to: HandTo.DancerForward, hand: Hand.Left }],
+            ]),
+          };
+          const balForwardPos = startWithBalHands.kind === PositionKind.Circle
+            ? {
+              ...startWithBalHands,
+              balance: BalanceWeight.Forward,
+              dancerDistance: DancerDistance.Compact,
+            }
+            : {
+              ...startWithBalHands,
+              balance: BalanceWeight.Forward,
+            };
+          return this.combine([
+            {
+              beats: balancePartBeats,
+              startPosition: startWithBalHands,
+              endPosition: balForwardPos,
+              movementPattern: { kind: SemanticAnimationKind.Linear, },
+            },
+            prevEnd => ({
+              beats: balancePartBeats,
+              endPosition: {
+                ...prevEnd,
+                balance: BalanceWeight.Backward,
+              },
+              movementPattern: { kind: SemanticAnimationKind.Linear, },
+            }),
+            swing,
+          ], startPosition);
+        case "meltdown":
+          const meltdownBeats = 4; // TODO right number here?
+          return this.combine([
+            prevEnd => ({
+              beats: meltdownBeats,
+              endPosition: { ...prevEnd, dancerDistance: DancerDistance.Compact },
+              movementPattern: {
+                kind: SemanticAnimationKind.RotateAround,
+                minAmount: 360,
+                around,
+                byHand: undefined,
+                close: true,
+              },
+            }),
+            swing,
+          ], startPosition);
+      }
+    });
+  }
+}
+
+class Swing extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new SwingSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, Swing);

www/js/moves/turnAlone.ts

@@ -0,0 +1,37 @@
+import { SemanticPosition } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "turn alone";
+
+class TurnAloneSingleVariant extends SingleVariantMoveInterpreter<TurnAlone, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    if (this.move.parameters.who !== "everyone" || this.move.beats !== 0) {
+      throw new Error("turn alone unsupported except for changing to new circle.");
+    }
+    return this.handleCircleMove(({ startPos }) => {
+      const which = startPos.which.swapUpAndDown();
+      const startAndEndPos: SemanticPosition = {
+        ...startPos,
+        which,
+        facing: which.facingUpOrDown(),
+        setOffset: (startPos.setOffset ?? 0) + (startPos.which.isTop() ? +0.5 : -0.5),
+      }
+
+      return this.combine([{
+        beats: this.move.beats,
+        endPosition: startAndEndPos,
+        movementPattern: { kind: SemanticAnimationKind.StandStill },
+      }], startAndEndPos);
+    });
+  }
+}
+
+class TurnAlone extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new TurnAloneSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, TurnAlone);

www/js/moves/upTheHall.ts

@@ -0,0 +1,95 @@
+import { Facing, ShortLinesPosition, PositionKind, CirclePosition, SemanticPosition, HandConnection, HandTo, handsInCircle } from "../interpreterCommon.js";
+import { Move } from "../libfigureMapper.js";
+import { SemanticAnimationKind } from "../lowLevelMove.js";
+import { Hand } from "../rendererConstants.js";
+import { ISingleVariantMoveInterpreter, LowLevelMovesForAllDancers, MoveInterpreter, SemanticPositionsForAllDancers, SingleVariantMoveInterpreter, moveInterpreters } from "./_moveInterpreter.js";
+
+const moveName: Move["move"] = "up the hall";
+
+// TODO Share implementation between up/down the hall?
+class UpTheHallSingleVariant extends SingleVariantMoveInterpreter<UpTheHall, typeof moveName> {
+  moveAsLowLevelMoves(): LowLevelMovesForAllDancers {
+    if (this.move.parameters.who !== "everyone") {
+      throw new Error("Don't know what it means for not everyone to go up the hall.");
+    }
+    if (this.move.parameters.moving !== "all") {
+      throw new Error("Not sure what it means for not all to be moving in up the hall.");
+    }
+    if (this.move.parameters.ender !== "circle") {
+      throw new Error("Unsupported up the hall ender: " + this.move.parameters.ender);
+    }
+    if (this.move.parameters.facing !== "forward") {
+      throw new Error("Unsupported up the hall facing: " + this.move.parameters.facing);
+    }
+
+    return this.handleMove(({ startPos }) => {
+      const startFacing = this.move.parameters.facing === "backward" ? Facing.Down : Facing.Up;
+      const startWhich: ShortLinesPosition = startPos.kind === PositionKind.ShortLines
+        ? startPos.which
+        // TODO Is this always the right way to convert circle to short lines?
+        //      (Does it even matter except for dance starting formations?)
+        : new Map<CirclePosition, ShortLinesPosition>([
+          [CirclePosition.TopLeft, ShortLinesPosition.MiddleLeft],
+          [CirclePosition.BottomLeft, ShortLinesPosition.FarLeft],
+          [CirclePosition.BottomRight, ShortLinesPosition.FarRight],
+          [CirclePosition.TopRight, ShortLinesPosition.MiddleRight],
+        ]).get(startPos.which)!;
+      const startingPos: SemanticPosition & { kind: PositionKind.ShortLines, setOffset: number } = {
+        kind: PositionKind.ShortLines,
+        facing: startFacing,
+        which: startWhich,
+        hands: startWhich.isMiddle() ? new Map<Hand, HandConnection>([
+          [Hand.Left, { hand: Hand.Left, to: HandTo.DancerLeft }],
+          [Hand.Right, { hand: Hand.Right, to: HandTo.DancerRight }],
+        ]) : new Map<Hand, HandConnection>([
+          startWhich.isLeft() === (this.move.parameters.facing === "backward")
+            ? [Hand.Right, { hand: Hand.Right, to: HandTo.DancerRight }]
+            : [Hand.Left, { hand: Hand.Left, to: HandTo.DancerLeft }]
+        ]),
+        setOffset: startPos.setOffset ?? 0,
+        lineOffset: startPos.lineOffset,
+      };
+      const endWhich = new Map<ShortLinesPosition, CirclePosition>([
+        [ShortLinesPosition.FarLeft, CirclePosition.TopLeft],
+        [ShortLinesPosition.MiddleLeft, CirclePosition.BottomLeft],
+        [ShortLinesPosition.MiddleRight, CirclePosition.BottomRight],
+        [ShortLinesPosition.FarRight, CirclePosition.TopRight],
+      ]).get(startWhich)!;
+      const endingPos: SemanticPosition & { kind: PositionKind.Circle } = {
+        kind: PositionKind.Circle,
+        which: endWhich,
+        facing: Facing.CenterOfCircle,
+        setOffset: startingPos.setOffset - 1,
+        lineOffset: startingPos.lineOffset,
+        hands: handsInCircle,
+      }
+
+      return this.combine([
+        {
+          beats: 4,
+          endPosition: {
+            ...startingPos,
+            setOffset: startingPos.setOffset - 1
+          },
+          movementPattern: { kind: SemanticAnimationKind.Linear },
+        },
+        {
+          beats: this.move.beats - 4,
+          endPosition: endingPos,
+          // TODO Is bend the line just linear?
+          movementPattern: {
+            kind: SemanticAnimationKind.Linear,
+            minRotation: startingPos.which.isLeft() ? -1 : +1
+          },
+        }], startingPos);
+    });
+  }
+}
+
+class UpTheHall extends MoveInterpreter<typeof moveName> {
+  buildSingleVariantMoveInterpreter(startingPos: SemanticPositionsForAllDancers): ISingleVariantMoveInterpreter {
+    return new UpTheHallSingleVariant(this, startingPos);
+  }
+}
+
+moveInterpreters.set(moveName, UpTheHall);

www/js/renderer.ts

@@ -1,99 +1,59 @@
 import { Animation } from "./animation.js";
 import { CoupleRole, DanceRole, DancerIdentity, ExtendedDancerIdentity } from "./danceCommon.js";
-import * as exampleAnimations from "./exampleAnimations.js";
 import { DancerSetPosition, DancersSetPositions, dancerHeight, dancerHeightOffset, leftShoulder, lineDistance, rightShoulder, setDistance, degreesToRadians } from "./rendererConstants.js";
 
 
 
-function hueForDancer(identity: DancerIdentity): number {
-  if (identity.coupleRole == CoupleRole.Ones) {
-    if (identity.danceRole == DanceRole.Lark) {
-      return 0; //red
+function baseColorForDancer(identity: ExtendedDancerIdentity): {hue: number, sat: number, lum: number} {
+  if (identity.setIdentity.coupleRole == CoupleRole.Ones) {
+    if (identity.relativeSet < 0)
+      return { hue: 340, sat: 67, lum: 56 };
+    if (identity.relativeSet === 0)
+      return { hue: 27, sat: 99, lum: 59 };
+    if (identity.relativeSet > 0)
+      return { hue: 54, sat: 97, lum: 49 };
   } else {
-      return 39; //orange
-    }
-  } else {
-    if (identity.danceRole == DanceRole.Lark) {
-      return 240; //blue
-    } else {
-      return 180; //teal
-    }
-  }
+    if (identity.relativeSet < 0)
+      return { hue: 183, sat: 88, lum: 23 };
+    if (identity.relativeSet === 0)
+      return { hue: 249, sat: 42, lum: 37 };
+    if (identity.relativeSet > 0)
+      return { hue: 13, sat: 33, lum: 29 };
   }
 
-const colorForDancerCache = new Map<DancerIdentity, string[]>(
-  DancerIdentity.all().map(id => [id,
-    [...Array(49).keys()]
-    .map(reverseColorCacheKey)
-    .map(({relativeSet, relativeLine}) => colorForDancer(id, relativeSet, relativeLine))]));
-
-const colorForDancerLabelCache = new Map<DancerIdentity, string[]>(
-  DancerIdentity.all().map(id => [id,
-    [...Array(49).keys()]
-    .map(i => reverseColorCacheKey(i))
-    .map(({relativeSet, relativeLine}) => colorForDancerLabel(id, relativeSet, relativeLine))]));
-
-function colorCacheKey(relativeSet: number, relativeLine: number) {
-  relativeSet = Math.max(-3, Math.min(3, relativeSet)) + 3;
-  relativeLine = Math.max(-3, Math.min(3, relativeLine)) + 3;
-
-  return relativeLine * 7 + relativeSet;
-}
-function reverseColorCacheKey(key: number): { relativeSet: number, relativeLine: number } {
-  return {
-    relativeSet: (key % 7) - 3,
-    relativeLine: Math.floor(key / 7) - 3,
-  }
+  throw new Error("Unreachable: relativeSet must be one of <, ===, or > 0.");
 }
 
-function colorForDancer(setIdentity: DancerIdentity, relativeSet: number, relativeLine: number) : string {
-  const hue = hueForDancer(setIdentity);
-  const sat = 100 - Math.abs(relativeLine * 40);
-  const unclampedLum = 50 + relativeSet * 20;
+function colorForDancer(identity: ExtendedDancerIdentity) : string {
+  const baseColor = baseColorForDancer(identity);
+
+  const hue = baseColor.hue;
+  const sat = baseColor.sat - Math.abs(identity.relativeLine * 40);
+  const unclampedLum = baseColor.lum + (Math.abs(identity.relativeSet) <= 1 ? 0 : identity.relativeSet * 20);
   const lum = unclampedLum < 10 ? 10 : unclampedLum > 90 ? 90 : unclampedLum;
   return `hsl(${hue}, ${sat}%, ${lum}%)`;
 }
 
-function colorForDancerCached(setIdentity: DancerIdentity, relativeSet: number, relativeLine: number) : string {
-  return colorForDancerCache.get(setIdentity)![colorCacheKey(relativeSet, relativeLine)];
-}
-
-function colorForDancerById(identity: ExtendedDancerIdentity) : string {
-  return colorForDancer(identity.setIdentity, identity.relativeSet, identity.relativeLine);
-}
-
-function colorForDancerLabel(setIdentity: DancerIdentity, relativeSet: number, relativeLine: number) : string {
-  const dancerHue = hueForDancer(setIdentity);
-  const hue = (dancerHue + 180) % 360;
+function colorForDancerLabel(identity: ExtendedDancerIdentity) : string {
+  const dancerColor = baseColorForDancer(identity);
+  const hue = (dancerColor.hue + 180) % 360;
   const sat = 100;
-  const lum = dancerHue === 240 && relativeSet < 2 || relativeSet < 0
+  const unclampedLum = ((dancerColor.hue >= 215 && dancerColor.hue <= 285) || (identity.relativeSet < 0)
+                      || dancerColor.lum < 40) && identity.relativeSet < 2
               ? 100
-              : 20 - relativeSet * 40;
+              : 20 - identity.relativeSet * 40;
+  const lum = unclampedLum < 0 ? 0 : unclampedLum > 100 ? 100 : unclampedLum;
   return `hsl(${hue}, ${sat}%, ${lum}%)`;
 }
 
-function colorForDancerLabelCached(setIdentity: DancerIdentity, relativeSet: number, relativeLine: number) : string {
-  return colorForDancerLabelCache.get(setIdentity)![colorCacheKey(relativeSet, relativeLine)];
-}
-
-function colorForDancerLabelById(identity: ExtendedDancerIdentity) : string {
-  return colorForDancerLabel(identity.setIdentity, identity.relativeSet, identity.relativeLine);
-}
-
-const positiveNumberStrings: string[] = [...Array(10).keys()].map(i => i.toString());
-const negativeNumberStrings: string[] = [...Array(10).keys()].map(i => (-i).toString());
-function cachedToString(smallNumber: number) {
-  if (Math.abs(smallNumber) >= 10) return smallNumber.toString();
-  if (smallNumber < 0) return negativeNumberStrings[-smallNumber];
-  else return positiveNumberStrings[smallNumber];
-}
-
 export class Renderer {
   canvas: HTMLCanvasElement;
   ctx: CanvasRenderingContext2D;
   animation?: Animation;
   extraSets?: number;
   extraLines?: number;
+  trailIncrements: number = 6;
+  trailLengthInBeats: number = 1;
   drawDebug: boolean = false;
 
   constructor(canvas: HTMLCanvasElement, ctx: CanvasRenderingContext2D) {
@@ -101,33 +61,41 @@ export class Renderer {
     this.ctx = ctx;
   }
 
-  drawDancerBody(setIdentity: DancerIdentity, relativeSet: number, relativeLine: number, drawText: boolean) {
+  drawDancerBody(identity: ExtendedDancerIdentity, drawText: boolean) {
     this.ctx.beginPath();
     this.ctx.moveTo(leftShoulder.x, leftShoulder.y);
+    if (identity.setIdentity.danceRole === DanceRole.Robin) {
+      // Draw triangle for robin.
       this.ctx.lineTo(rightShoulder.x, rightShoulder.y);
       this.ctx.lineTo(0, dancerHeight-dancerHeightOffset);
+    } else {
+      // Draw dome for lark.
+      this.ctx.arcTo(0, dancerHeight*2-dancerHeightOffset, rightShoulder.x, rightShoulder.y, dancerHeight * 1.5);
+      this.ctx.lineTo(rightShoulder.x, rightShoulder.y);
+    }
     this.ctx.fill();
 
     // Draw dot at origin to identify "center" point of dancer.
     const backupFillStyle = this.ctx.fillStyle;
     this.ctx.fillStyle = 'black';
+
     const pointSize = 0.05;
     this.ctx.fillRect(-pointSize/2, -pointSize/2, pointSize, pointSize);
 
-    if (drawText) {
+    if (drawText && identity) {
       this.ctx.save();
 
       this.ctx.scale(-1, 1);
       this.ctx.rotate(Math.PI);
-      this.ctx.fillStyle = colorForDancerLabelCached(setIdentity, relativeSet, relativeLine);
+      this.ctx.fillStyle = colorForDancerLabel(identity);
 
       this.ctx.font = '0.15px sans'
-      this.ctx.fillText(setIdentity.danceRole === DanceRole.Lark ? 'L' : 'R', -0.14, +0.04);
-      this.ctx.fillText(setIdentity.coupleRole === CoupleRole.Ones ? '1' : '2', +0.04, +0.04);
+      this.ctx.fillText(identity.setIdentity.danceRole === DanceRole.Lark ? 'L' : 'R', -0.14, +0.04);
+      this.ctx.fillText(identity.setIdentity.coupleRole === CoupleRole.Ones ? '1' : '2', +0.04, +0.04);
 
       this.ctx.font = '0.1px sans'
-      this.ctx.fillText(cachedToString(relativeLine), +0.14, +0.04);
-      this.ctx.fillText(cachedToString(relativeSet), -0.22, +0.04);
+      this.ctx.fillText(identity.relativeLine.toString(), +0.14, +0.04);
+      this.ctx.fillText(identity.relativeSet.toString(), -0.22, +0.04);
 
       this.ctx.restore();
     }
@@ -140,8 +108,11 @@ export class Renderer {
 
     this.ctx.translate(identity.relativeLine * lineDistance,
                         identity.relativeSet * setDistance);
-    const relativeSet = identity.relativeSet + (offsetSets * (identity.setIdentity.coupleRole === CoupleRole.Ones ? 1 : -1));
-    this.ctx.fillStyle = this.ctx.strokeStyle = colorForDancerCached(identity.setIdentity, relativeSet, identity.relativeLine);
+    const realIdentity = {
+      ...identity,
+      relativeSet: identity.relativeSet + (offsetSets * (identity.setIdentity.coupleRole === CoupleRole.Ones ? 1 : -1))
+    };
+    this.ctx.fillStyle = this.ctx.strokeStyle = colorForDancer(realIdentity);
 
     if (drawDebug) {
       if (this.drawDebug && position.drawDebug) {
@@ -154,7 +125,7 @@ export class Renderer {
       this.ctx.translate(position.position.x, position.position.y);
       this.ctx.rotate(-degreesToRadians(position.rotation));
 
-      this.drawDancerBody(identity.setIdentity, relativeSet, identity.relativeLine, drawText);
+      this.drawDancerBody(realIdentity, drawText);
 
       // Draw arms.
       this.ctx.lineWidth = 0.03;
@@ -201,16 +172,15 @@ export class Renderer {
     if (!this.animation) throw new Error("Attempted to render before setting animation.");
 
     this.clear();
-    const increments = 7;
-    const trailLengthInBeats = 1;
-    const incrementLength = trailLengthInBeats / increments;
+    const increments = this.trailLengthInBeats > 0 && this.trailIncrements > 0 ? this.trailIncrements : 0;
+    const incrementLength = this.trailLengthInBeats / (increments + 1);
     progression ??= 0;
     const offsetSets = this.animation.progression.y === 0
       ? 0
       : -((progression - (progression % 2)) / 2) / ((this.animation.progression.y * 2) / setDistance);
     for (var i = increments; i >= 0; i--) {
-      const beatToDraw = beat - i*incrementLength;
-      this.ctx.globalAlpha = i == 0 ? 1 : (1 - i/increments)*0.3;
+      const beatToDraw = i == 0 ? beat : beat - i*incrementLength;
+      this.ctx.globalAlpha = i == 0 ? 1 : (1 - i / (increments + 1)) * 0.3;
       const positions = this.animation.positionsAtBeat(beatToDraw, progression % 2);
       if (this.drawDebug) this.drawSets(positions, offsetSets, true, true);
       this.drawSets(positions, offsetSets, i === 0, false);
@@ -246,9 +216,9 @@ export class Renderer {
     for (var relativeLine = -extraLines; relativeLine <= extraLines; relativeLine++) {
       for (var relativeSet = -extraSets; relativeSet <= extraSets; relativeSet++) {
         this.ctx.save();
-        const hue = (relativeLine + relativeSet) % 2 === 0 ? 60 : 170;
-        const sat = 100 - Math.abs(relativeLine * 40);
-        const lum = Math.min(98, 90 + Math.abs(relativeSet) * 5);
+        const hue = 0;
+        const sat = 0;
+        const lum = Math.min(98, 90 + Math.abs(Math.abs(relativeSet) + Math.abs(relativeLine)) * 5);
         this.ctx.fillStyle = `hsl(${hue}, ${sat}%, ${lum}%)`;
         this.ctx.translate(relativeLine * lineDistance,
                            relativeSet * setDistance);