implement copy paste

src/App/App.tsx

@@ -14,6 +14,7 @@ import { TopPanel } from "./TopPanel";
 import { RTHistory } from "./RTHistory";
 import { AST } from "./AST";
 import { TraceableError } from "../statecharts/parser";
+import { getKeyHandler } from "./shortcut_handler";
 
 export function App() {
   const [mode, setMode] = useState<InsertMode>("and");
@@ -83,6 +84,14 @@ export function App() {
 
   }, [time, rtIdx]);
 
+  useEffect(() => {
+    const onKeyDown = getKeyHandler(setMode);
+    window.addEventListener("keydown", onKeyDown);
+    return () => {
+      window.removeEventListener("keydown", onKeyDown);
+    };
+  }, []);
+
   return <Stack sx={{height:'100vh'}}>
     {/* Top bar */}
     <Box

src/App/RTHistory.tsx

@@ -31,11 +31,11 @@ export function RTHistory({rt, rtIdx, ast, setRTIdx, setTime}: RTHistoryProps) {
 
 
 function ShowEnvironment(props: {environment: Environment}) {
-  return <div>{[...props.environment.entries()]
+  return <div>{
+    [...props.environment.entries()]
       .filter(([variable]) => !variable.startsWith('_'))
-    .map(([variable,value]) =>
+      .map(([variable,value]) => `${variable}: ${value}`).join(', ')
-    `${variable}: ${value}`
+  }</div>;
-  ).join(', ')}</div>;
 }
 
 function ShowMode(props: {mode: Mode, statechart: Statechart}) {

src/App/TopPanel.tsx

@@ -116,7 +116,7 @@ export function TopPanel({rt, time, setTime, onInit, onClear, onRaise, ast, mode
     </div>
     &emsp;
     <div className="toolbar">
-    <button title="(re)initialize simulation" onClick={onInit} ><CachedIcon fontSize="small"/></button>
+    <button title="(re)initialize simulation" onClick={onInit} ><CachedIcon fontSize="small"/><PlayArrowIcon fontSize="small"/></button>
     <button title="clear the simulation" onClick={onClear} disabled={!rt}><ClearIcon fontSize="small"/></button>
 
     &emsp;

src/App/shortcut_handler.ts

@@ -0,0 +1,22 @@
+import { Dispatch, SetStateAction } from "react";
+import { InsertMode } from "../VisualEditor/VisualEditor";
+
+export function getKeyHandler(setMode: Dispatch<SetStateAction<InsertMode>>) {
+  return function onKeyDown(e: KeyboardEvent) {
+    if (e.key === "a") {
+      setMode("and");
+    }
+    if (e.key === "o") {
+      setMode("or");
+    }
+    if (e.key === "p") {
+      setMode("pseudo");
+    }
+    if (e.key === "t") {
+      setMode("transition");
+    }
+    if (e.key === "x") {
+      setMode("text");
+    }
+  }
+}

src/VisualEditor/VisualEditor.css

@@ -81,7 +81,7 @@ text.highlight {
 .lineHelper:hover {
   stroke: blue;
   stroke-opacity: 0.2;
-  cursor: grab;
+  /* cursor: grab; */
 }
 
 .pathHelper {
@@ -102,7 +102,7 @@ text.highlight {
 .circleHelper:hover {
   fill: blue;
   fill-opacity: 0.2;
-  cursor: grab;
+  /* cursor: grab; */
 }
 
 .rountangle.or {

src/VisualEditor/VisualEditor.tsx

@@ -2,7 +2,7 @@ import * as lz4 from "@nick/lz4";
 import { Dispatch, SetStateAction, useEffect, useRef, useState, MouseEvent } from "react";
 
 import { Statechart } from "../statecharts/abstract_syntax";
-import { ArrowPart, RountanglePart, VisualEditorState, emptyState, findNearestArrow, findNearestRountangleSide, findRountangle } from "../statecharts/concrete_syntax";
+import { Arrow, ArrowPart, Rountangle, RountanglePart, Text, VisualEditorState, emptyState, findNearestArrow, findNearestRountangleSide, findRountangle } from "../statecharts/concrete_syntax";
 import { parseStatechart, TraceableError } from "../statecharts/parser";
 import { BigStep } from "../statecharts/runtime_types";
 import { ArcDirection, Line2D, Rect2D, Vec2D, addV2D, arcDirection, area, getBottomSide, getLeftSide, getRightSide, getTopSide, isEntirelyWithin, normalizeRect, subtractV2D, transformLine, transformRect } from "./geometry";
@@ -63,6 +63,8 @@ type VisualEditorProps = {
 export function VisualEditor({setAST, rt, errors, setErrors, mode}: VisualEditorProps) {
   const [historyState, setHistoryState] = useState<HistoryState>({current: emptyState, history: [], future: []});
 
+  const [clipboard, setClipboard] = useState<Set<string>>(new Set());
+
   const state = historyState.current;
   const setState = (s: SetStateAction<VisualEditorState>) => {
     setHistoryState(historyState => {
@@ -164,7 +166,7 @@ export function VisualEditor({setAST, rt, errors, setErrors, mode}: VisualEditor
   const onMouseDown = (e: MouseEvent) => {
     const currentPointer = getCurrentPointer(e);
 
-    if (e.button === 1) {
+    if (e.button === 2) {
       checkPoint();
       // ignore selection, middle mouse button always inserts
       setState(state => {
@@ -230,10 +232,11 @@ export function VisualEditor({setAST, rt, errors, setErrors, mode}: VisualEditor
             break;
           }
         }
-        if (!allPartsInSelection) {
+        // if (!allPartsInSelection) {
-          setSelection([{uid, parts}] as Selection);
+        //   setSelection([{uid, parts}] as Selection);
-        }
+        // }
 
+        if (allPartsInSelection) {
           // start dragging
           setDragging({
             lastMousePos: currentPointer,
@@ -241,7 +244,6 @@ export function VisualEditor({setAST, rt, errors, setErrors, mode}: VisualEditor
           return;
         }
       }
-
       // otherwise, just start making a selection
       setDragging(null);
       setSelectingState({
@@ -249,6 +251,7 @@ export function VisualEditor({setAST, rt, errors, setErrors, mode}: VisualEditor
         size: {x: 0, y: 0},
       });
       setSelection([]);
+    }
   };
 
   const onMouseMove = (e: {pageX: number, pageY: number}) => {
@@ -304,7 +307,7 @@ export function VisualEditor({setAST, rt, errors, setErrors, mode}: VisualEditor
     }
   };
 
-  const onMouseUp = () => {
+  const onMouseUp = (e) => {
     if (dragging) {
       setDragging(null);
       // do not persist sizes smaller than 40x40
@@ -320,6 +323,25 @@ export function VisualEditor({setAST, rt, errors, setErrors, mode}: VisualEditor
     }
     if (selectingState) {
       // we were making a selection
+      if (selectingState.size.x === 0 && selectingState.size.y === 0) {
+        const uid = e.target?.dataset.uid;
+        const parts: string[] = e.target?.dataset.parts?.split(' ') || [];
+        if (uid) {
+          checkPoint();
+          // @ts-ignore
+          setSelection(() => ([{uid, parts}]));
+
+          // if the mouse button is pressed outside of the current selection, we reset the selection to whatever shape the mouse is on
+          let allPartsInSelection = true;
+          for (const part of parts) {
+            if (!(selection.find(s => s.uid === uid)?.parts || [] as string[]).includes(part)) {
+              allPartsInSelection = false;
+              break;
+            }
+          }
+        }
+      }
+      else {
         const normalizedSS = normalizeRect(selectingState);
         const shapes = Array.from(refSVG.current?.querySelectorAll("rect, line, circle, text") || []) as SVGGraphicsElement[];
         const shapesInSelection = shapes.filter(el => {
@@ -339,19 +361,15 @@ export function VisualEditor({setAST, rt, errors, setErrors, mode}: VisualEditor
           }
         }
         setSelection(() => [...uidToParts.entries()].map(([uid,parts]) => ({
-        kind: "rountangle",
           uid,
           parts: [...parts],
         })));
-      setSelectingState(null); // no longer making a selection
       }
+    }
+    setSelectingState(null); // no longer making a selection
   };
 
-  const onKeyDown = (e: KeyboardEvent) => {
+  function deleteShapes(selection: Selection) {
-    if (e.key === "Delete") {
-      // delete selection
-      if (selection.length > 0) {
-        checkPoint();
     setState(state => ({
       ...state,
       rountangles: state.rountangles.filter(r => !selection.some(rs => rs.uid === r.uid)),
@@ -360,6 +378,14 @@ export function VisualEditor({setAST, rt, errors, setErrors, mode}: VisualEditor
     }));
     setSelection([]);
   }
+
+  const onKeyDown = (e: KeyboardEvent) => {
+    if (e.key === "Delete") {
+      // delete selection
+      if (selection.length > 0) {
+        checkPoint();
+        deleteShapes(selection);
+      }
     }
     if (e.key === "o") {
       // selected states become OR-states
@@ -394,17 +420,61 @@ export function VisualEditor({setAST, rt, errors, setErrors, mode}: VisualEditor
     if (e.key === "h") {
       setShowHelp(showHelp => !showHelp);
     }
-    // if (e.key === "s") {
-    //   setMode("state");
-    // }
-    // if (e.key === "t") {
-    //   setMode("transition");
-    // }
-    // if (e.key === "x") {
-    //   setMode("text");
-    // }
-
     if (e.ctrlKey) {
+      // if (e.key === "c") {
+      //   if (selection.length > 0) {
+      //     e.preventDefault();
+      //     setClipboard(new Set(selection.map(shape => shape.uid)));
+      //     console.log('set clipboard', new Set(selection.map(shape => shape.uid)));
+      //   }
+      // }
+      // if (e.key === "v") {
+      //   console.log('paste shortcut..', clipboard);
+      //   if (clipboard.size > 0) {
+      //     console.log('pasting...a');
+      //     e.preventDefault();
+      //     checkPoint();
+      //     const offset = {x: 40, y: 40};
+      //     const rountanglesToCopy = state.rountangles.filter(r => clipboard.has(r.uid));
+      //     const arrowsToCopy = state.arrows.filter(a => clipboard.has(a.uid));
+      //     const textsToCopy = state.texts.filter(t => clipboard.has(t.uid));
+      //     let nextUid = state.nextID;
+      //     const rountanglesCopied: Rountangle[] = rountanglesToCopy.map(r => ({
+      //       ...r,
+      //       uid: (nextUid++).toString(),
+      //       topLeft: addV2D(r.topLeft, offset),
+      //     }));
+      //     const arrowsCopied: Arrow[] = arrowsToCopy.map(a => ({
+      //       ...a,
+      //       uid: (nextUid++).toString(),
+      //       start: addV2D(a.start, offset),
+      //       end: addV2D(a.end, offset),
+      //     }));
+      //     const textsCopied: Text[] = textsToCopy.map(t => ({
+      //       ...t,
+      //       uid: (nextUid++).toString(),
+      //       topLeft: addV2D(t.topLeft, offset),
+      //     }));
+      //     setState(state => ({
+      //       ...state,
+      //       rountangles: [...state.rountangles, ...rountanglesCopied],
+      //       arrows: [...state.arrows, ...arrowsCopied],
+      //       texts: [...state.texts, ...textsCopied],
+      //       nextID: nextUid,
+      //     }));
+      //     setClipboard(new Set([
+      //       ...rountanglesCopied.map(r => r.uid),
+      //       ...arrowsCopied.map(a => a.uid),
+      //       ...textsCopied.map(t => t.uid),
+      //     ]));
+      //     // @ts-ignore
+      //     setSelection([
+      //       ...rountanglesCopied.map(r => ({uid: r.uid, parts: ["left", "top", "right", "bottom"]})),
+      //       ...arrowsCopied.map(a => ({uid: a.uid, parts: ["start", "end"]})),
+      //       ...textsCopied.map(t => ({uid: t.uid, parts: ["text"]})),
+      //     ]);
+      //   }
+      // }
       if (e.key === "z") {
         e.preventDefault();
         undo();
@@ -441,7 +511,7 @@ export function VisualEditor({setAST, rt, errors, setErrors, mode}: VisualEditor
       window.removeEventListener("mousemove", onMouseMove);
       window.removeEventListener("mouseup", onMouseUp);
     };
-  }, [selectingState, dragging]);
+  }, [selectingState, dragging, clipboard]);
 
   // detect what is 'connected'
   const arrow2SideMap = new Map<string,[{ uid: string; part: RountanglePart; } | undefined, { uid: string; part: RountanglePart; } | undefined]>();
@@ -525,6 +595,86 @@ export function VisualEditor({setAST, rt, errors, setErrors, mode}: VisualEditor
     }
   }
 
+  function onPaste(e: ClipboardEvent) {
+    const data = e.clipboardData?.getData("text/plain");
+    if (data) {
+      let parsed;
+      try {
+        parsed = JSON.parse(data);
+      }
+      catch (e) {
+        return;
+      }
+      // const offset = {x: 40, y: 40};
+      const offset = {x: 0, y: 0};
+      let nextID = state.nextID;
+      try {
+        const copiedRountangles: Rountangle[] = parsed.rountangles.map((r: Rountangle) => ({
+          ...r,
+          uid: (nextID++).toString(),
+          topLeft: addV2D(r.topLeft, offset),
+        } as Rountangle));
+        const copiedArrows: Arrow[] = parsed.arrows.map((a: Arrow) => ({
+          ...a,
+          uid: (nextID++).toString(),
+          start: addV2D(a.start, offset),
+          end: addV2D(a.end, offset),
+        } as Arrow));
+        const copiedTexts: Text[] = parsed.texts.map((t: Text) => ({
+          ...t,
+          uid: (nextID++).toString(),
+          topLeft: addV2D(t.topLeft, offset),
+        } as Text));
+        setState(state => ({
+          ...state,
+          rountangles: [...state.rountangles, ...copiedRountangles],
+          arrows: [...state.arrows, ...copiedArrows],
+          texts: [...state.texts, ...copiedTexts],
+          nextID: nextID,
+        }));
+        // @ts-ignore
+        const newSelection: Selection = [
+          ...copiedRountangles.map(r => ({uid: r.uid, parts: ["left", "top", "right", "bottom"]})),
+          ...copiedArrows.map(a => ({uid: a.uid, parts: ["start", "end"]})),
+          ...copiedTexts.map(t => ({uid: t.uid, parts: ["text"]})),
+        ];
+        setSelection(newSelection);
+        // copyInternal(newSelection, e); // doesn't work
+        e.preventDefault();
+      }
+      catch (e) {
+      }
+    }
+  }
+
+  function copyInternal(selection: Selection, e: ClipboardEvent) {
+    const uidsToCopy = new Set(selection.map(shape => shape.uid));
+    const rountanglesToCopy = state.rountangles.filter(r => uidsToCopy.has(r.uid));
+    const arrowsToCopy = state.arrows.filter(a => uidsToCopy.has(a.uid));
+    const textsToCopy = state.texts.filter(t => uidsToCopy.has(t.uid));
+    e.clipboardData?.setData("text/plain", JSON.stringify({
+      rountangles: rountanglesToCopy,
+      arrows: arrowsToCopy,
+      texts: textsToCopy,
+    }));
+  }
+
+  function onCopy(e: ClipboardEvent) {
+    if (selection.length > 0) {
+      e.preventDefault();
+      copyInternal(selection, e);
+    }
+  }
+
+  function onCut(e: ClipboardEvent) {
+    if (selection.length > 0) {
+      copyInternal(selection, e);
+      deleteShapes(selection);
+      e.preventDefault();
+    }
+    
+  }
+
   const active = rt?.mode || new Set();
 
   const rootErrors = errors.filter(({shapeUid}) => shapeUid === "root").map(({message}) => message);
@@ -534,6 +684,9 @@ export function VisualEditor({setAST, rt, errors, setErrors, mode}: VisualEditor
       onMouseDown={onMouseDown}
       onContextMenu={e => e.preventDefault()}
       ref={refSVG}
+      onCopy={onCopy}
+      onPaste={onPaste}
+      onCut={onCut}
     >
       <defs>
         <marker
@@ -637,30 +790,6 @@ export function VisualEditor({setAST, rt, errors, setErrors, mode}: VisualEditor
       >{textNode}</g>;})}
 
     {selectingState && <Selecting {...selectingState} />}
-
-    {/* {showHelp ? <>
-      <text x={5} y={20}>
-        Left mouse button: Select/Drag.
-      </text>
-      <text x={5} y={40}>
-        Right mouse button: Select only.
-      </text>
-      <text x={5} y={60}>
-        Middle mouse button: Insert [S]tates / [T]ransitions / Te[X]t (current mode: {mode})</text>
-      <text x={5} y={80}>
-        [Del] Delete selection.
-      </text>
-      <text x={5} y={100}>
-        [O] Turn selected states into OR-states.
-      </text>
-      <text x={5} y={120}>
-        [A] Turn selected states into AND-states.
-      </text>
-      <text x={5} y={140}>
-        [H] Show/hide this help.
-      </text>
-    </> : <text x={5} y={20}>[H] To show help.</text>} */}
-
   </svg>;
 }
 

src/statecharts/abstract_syntax.ts

@@ -1,4 +1,4 @@
-import { Action, EventTrigger, TransitionLabel } from "./label_ast";
+import { Action, EventTrigger, ParsedText, TransitionLabel } from "./label_ast";
 
 export type AbstractState = {
   uid: string;
@@ -28,7 +28,7 @@ export type Transition = {
   uid: string;
   src: ConcreteState;
   tgt: ConcreteState;
-  label: TransitionLabel[];
+  label: ParsedText[];
 }
 
 export type Statechart = {

src/statecharts/actionlang_interpreter.ts

@@ -3,7 +3,6 @@
 import { Expression } from "./label_ast";
 import { Environment } from "./runtime_types";
 
-
 const UNARY_OPERATOR_MAP: Map<string, (x: any) => any> = new Map([
   ["!", x => !x],
   ["-", x => -x as any],

src/statecharts/interpreter.ts

@@ -1,11 +1,11 @@
 import { evalExpr } from "./actionlang_interpreter";
 import { computeArena, ConcreteState, getDescendants, isOverlapping, OrState, Statechart, stateDescription, Transition } from "./abstract_syntax";
-import { Action, EventTrigger } from "./label_ast";
+import { Action, AfterTrigger, EventTrigger } from "./label_ast";
-import { Environment, RaisedEvents, Mode, RT_Statechart, initialRaised, BigStepOutput, Timers, RT_Event } from "./runtime_types";
+import { Environment, RaisedEvents, Mode, RT_Statechart, initialRaised, BigStepOutput, Timers, RT_Event, TimerElapseEvent } from "./runtime_types";
 
 export function initialize(ast: Statechart): BigStepOutput {
   let {enteredStates, environment, ...raised} = enterDefault(0, ast.root, {
-    environment: new Map(),
+    environment: new Environment(),
     ...initialRaised,
   });
   return handleInternalEvents(0, ast, {mode: enteredStates, environment, ...raised});
@@ -23,14 +23,19 @@ export function entryActions(simtime: number, state: ConcreteState, actionScope:
   }
   // schedule timers
   // we store timers in the environment (dirty!)
-  const environment = new Map(actionScope.environment);
+  let environment = actionScope.environment.transform<Timers>("_timers", oldTimers => {
-  const timers: Timers = [...(environment.get("_timers") || [])];
+    const newTimers = [
-  for (const timeOffset of state.timers) {
+      ...oldTimers,
-    const futureSimTime = simtime + timeOffset; // point in simtime when after-trigger becomes enabled
+      ...state.timers.map(timeOffset => {
-    timers.push([futureSimTime, {kind: "timer", state: state.uid, timeDurMs: timeOffset}]);
+        const futureSimTime = simtime + timeOffset;
-  }
+        return [futureSimTime, {kind: "timer", state: state.uid, timeDurMs: timeOffset}] as [number, TimerElapseEvent];
-  timers.sort((a,b) => a[0] - b[0]); // smallest futureSimTime comes first
+      }),
-  environment.set("_timers", timers);
+    ];
+    newTimers.sort((a,b) => a[0] - b[0]);
+    return newTimers;
+  }, []);
+  // new nested scope
+  environment = environment.pushScope();
   return {...actionScope, environment};
 }
 
@@ -38,11 +43,12 @@ export function exitActions(simtime: number, state: ConcreteState, actionScope:
   for (const action of state.exitActions) {
     (actionScope = execAction(action, actionScope));
   }
+  let environment = actionScope.environment.popScope();
   // cancel timers
-  const environment = new Map(actionScope.environment);
+  environment = environment.transform<Timers>("_timers", oldTimers => {
-  const timers: Timers = environment.get("_timers") || [];
+    // remove all timers of 'state':
-  const filtered = timers.filter(([_, {state: s}]) => s !== state.uid);
+    return oldTimers.filter(([_, {state: s}]) => s !== state.uid);
-  environment.set("_timers", filtered);
+  }, []);
   return {...actionScope, environment};
 }
 
@@ -124,15 +130,15 @@ export function enterPath(simtime: number, path: ConcreteState[], rt: ActionScop
 export function exitCurrent(simtime: number, state: ConcreteState, rt: EnteredScope): ActionScope {
   let {enteredStates, ...actionScope} = rt;
 
+  if (enteredStates.has(state.uid)) {
     // exit all active children...
     for (const child of state.children) {
-    if (enteredStates.has(child.uid)) {
       actionScope = exitCurrent(simtime, child,  {enteredStates, ...actionScope});
     }
-  }
 
     // execute exit actions
     actionScope = exitActions(simtime, state, actionScope);
+  }
 
   return actionScope;
 }
@@ -140,7 +146,7 @@ export function exitCurrent(simtime: number, state: ConcreteState, rt: EnteredSc
 export function exitPath(simtime: number, path: ConcreteState[], rt: EnteredScope): ActionScope {
   let {enteredStates, ...actionScope} = rt;
 
-  const toExit = enteredStates.difference(new Set(path));
+  const toExit = enteredStates.difference(new Set(path.map(s=>s.uid)));
 
   const [state, ...rest] = path;
   
@@ -152,18 +158,16 @@ export function exitPath(simtime: number, path: ConcreteState[], rt: EnteredScop
 
   // execute exit actions
   actionScope = exitActions(simtime, state, actionScope);
-
   return actionScope;
 }
 
 export function execAction(action: Action, rt: ActionScope): ActionScope {
   if (action.kind === "assignment") {
     const rhs = evalExpr(action.rhs, rt.environment);
-    const newEnvironment = new Map(rt.environment);
+    const environment = rt.environment.set(action.lhs, rhs);
-    newEnvironment.set(action.lhs, rhs);
     return {
       ...rt,
-      environment: newEnvironment,
+      environment,
     };
   }
   else if (action.kind === "raise") {
@@ -224,7 +228,6 @@ export function handleEvent(simtime: number, event: RT_Event, statechart: Statec
           console.warn('nondeterminism!!!!');
         }
         const t = enabled[0];
-        console.log('enabled:', transitionDescription(t));
         const {arena, srcPath, tgtPath} = computeArena(t);
         let overlapping = false;
         for (const alreadyFired of arenasFired) {
@@ -233,30 +236,25 @@ export function handleEvent(simtime: number, event: RT_Event, statechart: Statec
           }
         }
         if (!overlapping) {
-          console.log('^ firing');
           let oldValue;
           if (event.kind === "input" && event.param !== undefined) {
             // input events may have a parameter
-            // *temporarily* add event to environment (dirty!)
+            // add event parameter to environment in new scope
-            oldValue = environment.get(event.param);
+            environment = environment.pushScope();
-            environment = new Map([
+            environment = environment.newVar(
-              ...environment,
+              (t.label[0].trigger as EventTrigger).paramName as string,
-              [(t.label[0].trigger as EventTrigger).paramName as string, event.param],
+              event.param,
-            ]);
+            );
           }
           ({mode, environment, ...raised} = fireTransition(simtime, t, arena, srcPath, tgtPath, {mode, environment, ...raised}));
           if (event.kind === "input" && event.param) {
-            // restore original value of variable that had same name as input parameter
+            environment = environment.popScope();
-            environment = new Map([
+            // console.log('restored environment:', environment);
-              ...environment,
-              [(t.label[0].trigger as EventTrigger).paramName as string, oldValue],
-            ]);
-            console.log('restored environment:', environment);
           }
           arenasFired.add(arena);
         }
         else {
-          console.log('skip (overlapping arenas)');
+          // console.log('skip (overlapping arenas)');
         }
       }
       else {
@@ -292,9 +290,10 @@ function transitionDescription(t: Transition) {
 
 export function fireTransition(simtime: number, t: Transition, arena: OrState, srcPath: ConcreteState[], tgtPath: ConcreteState[], {mode, environment, ...raised}: RT_Statechart & RaisedEvents): RT_Statechart & RaisedEvents {
 
-  // console.log('fire ', transitionDescription(t), {arena, srcPath, tgtPath});
+  console.log('fire ', transitionDescription(t), {arena, srcPath, tgtPath});
 
   // exit src
+  console.log('exit src...');
   ({environment, ...raised} = exitPath(simtime, srcPath.slice(1), {environment, enteredStates: mode, ...raised}));
   const toExit = getDescendants(arena);
   toExit.delete(arena.uid); // do not exit the arena itself
@@ -306,6 +305,7 @@ export function fireTransition(simtime: number, t: Transition, arena: OrState, s
   }
 
   // enter tgt
+  console.log('enter tgt...');
   let enteredStates;
   ({enteredStates, environment, ...raised} = enterPath(simtime, tgtPath.slice(1), {environment, ...raised}));
   const enteredMode = exitedMode.union(enteredStates);

src/statecharts/label_ast.ts

@@ -1,4 +1,4 @@
-export type ParsedText = TransitionLabel | Comment;
+export type ParsedText = TransitionLabel | Comment | ParserError;
 
 export type TransitionLabel = {
   kind: "transitionLabel";
@@ -14,6 +14,11 @@ export type Comment = {
   text: string;
 }
 
+export type ParserError = {
+  kind: "parserError";
+  uid: string; // uid of the text node
+}
+
 export type Trigger = EventTrigger | AfterTrigger | EntryTrigger | ExitTrigger;
 
 export type EventTrigger = {
@@ -74,3 +79,9 @@ export type Literal = {
   kind: "literal";
   value: any;
 }
+
+export type FunctionCall = {
+  kind: "call",
+  fn: VarRef,
+  param: Expression,
+}

src/statecharts/label_parser.js

@@ -182,16 +182,18 @@ function peg$parse(input, options) {
   const peg$c15 = ">=";
   const peg$c16 = "true";
   const peg$c17 = "false";
-  const peg$c18 = "^";
+  const peg$c18 = "\"";
-  const peg$c19 = "//";
+  const peg$c19 = "^";
-  const peg$c20 = "\n";
+  const peg$c20 = "//";
+  const peg$c21 = "\n";
 
   const peg$r0 = /^[0-9A-Z_a-z]/;
   const peg$r1 = /^[0-9]/;
   const peg$r2 = /^[<>]/;
   const peg$r3 = /^[+\-]/;
   const peg$r4 = /^[*\/]/;
-  const peg$r5 = /^[ \t\n\r]/;
+  const peg$r5 = /^[^"]/;
+  const peg$r6 = /^[ \t\n\r]/;
 
   const peg$e0 = peg$literalExpectation("[", false);
   const peg$e1 = peg$literalExpectation("]", false);
@@ -216,11 +218,13 @@ function peg$parse(input, options) {
   const peg$e20 = peg$classExpectation(["*", "/"], false, false, false);
   const peg$e21 = peg$literalExpectation("true", false);
   const peg$e22 = peg$literalExpectation("false", false);
-  const peg$e23 = peg$literalExpectation("^", false);
+  const peg$e23 = peg$literalExpectation("\"", false);
-  const peg$e24 = peg$classExpectation([" ", "\t", "\n", "\r"], false, false, false);
+  const peg$e24 = peg$classExpectation(["\""], true, false, false);
-  const peg$e25 = peg$literalExpectation("//", false);
+  const peg$e25 = peg$literalExpectation("^", false);
-  const peg$e26 = peg$anyExpectation();
+  const peg$e26 = peg$classExpectation([" ", "\t", "\n", "\r"], false, false, false);
-  const peg$e27 = peg$literalExpectation("\n", false);
+  const peg$e27 = peg$literalExpectation("//", false);
+  const peg$e28 = peg$anyExpectation();
+  const peg$e29 = peg$literalExpectation("\n", false);
 
   function peg$f0(trigger, guard, actions) {
     return {
@@ -296,20 +300,30 @@ function peg$parse(input, options) {
   function peg$f14(expr) {
     return expr;
   }
-  function peg$f15(value) {
+  function peg$f15(fn, param) {
+    return {
+    	kind: "call",
+        fn,
+        param,
+    };
+  }
+  function peg$f16(value) {
     return {kind: "literal", value}
   }
-  function peg$f16(variable) {
+  function peg$f17(variable) {
     return {kind: "ref", variable}
   }
-  function peg$f17() {
+  function peg$f18() {
     return text() === "true";
   }
-  function peg$f18(event, param) {
+  function peg$f19(str) {
+    return str.join('');
+  }
+  function peg$f20(event, param) {
     return {kind: "raise", event, param: param ? param[1] : undefined};
   }
-  function peg$f19() {    return null;  }
+  function peg$f21() {    return null;  }
-  function peg$f20(text) {
+  function peg$f22(text) {
     return {
     	kind: "comment",
         text: text.join(''),
@@ -1152,6 +1166,8 @@ function peg$parse(input, options) {
   function peg$parseatom() {
     let s0;
 
+    s0 = peg$parsefnCall();
+    if (s0 === peg$FAILED) {
       s0 = peg$parsenested();
       if (s0 === peg$FAILED) {
         s0 = peg$parseliteral();
@@ -1159,6 +1175,7 @@ function peg$parse(input, options) {
           s0 = peg$parseref();
         }
       }
+    }
 
     return s0;
   }
@@ -1205,6 +1222,28 @@ function peg$parse(input, options) {
     return s0;
   }
 
+  function peg$parsefnCall() {
+    let s0, s1, s2;
+
+    s0 = peg$currPos;
+    s1 = peg$parseref();
+    if (s1 !== peg$FAILED) {
+      s2 = peg$parsenested();
+      if (s2 !== peg$FAILED) {
+        peg$savedPos = s0;
+        s0 = peg$f15(s1, s2);
+      } else {
+        peg$currPos = s0;
+        s0 = peg$FAILED;
+      }
+    } else {
+      peg$currPos = s0;
+      s0 = peg$FAILED;
+    }
+
+    return s0;
+  }
+
   function peg$parseliteral() {
     let s0, s1;
 
@@ -1212,10 +1251,13 @@ function peg$parse(input, options) {
     s1 = peg$parsenumber();
     if (s1 === peg$FAILED) {
       s1 = peg$parseboolean();
+      if (s1 === peg$FAILED) {
+        s1 = peg$parsestring();
+      }
     }
     if (s1 !== peg$FAILED) {
       peg$savedPos = s0;
-      s1 = peg$f15(s1);
+      s1 = peg$f16(s1);
     }
     s0 = s1;
 
@@ -1229,7 +1271,7 @@ function peg$parse(input, options) {
     s1 = peg$parseidentifier();
     if (s1 !== peg$FAILED) {
       peg$savedPos = s0;
-      s1 = peg$f16(s1);
+      s1 = peg$f17(s1);
     }
     s0 = s1;
 
@@ -1258,23 +1300,75 @@ function peg$parse(input, options) {
     }
     if (s1 !== peg$FAILED) {
       peg$savedPos = s0;
-      s1 = peg$f17();
+      s1 = peg$f18();
     }
     s0 = s1;
 
     return s0;
   }
 
+  function peg$parsestring() {
+    let s0, s1, s2, s3;
+
+    s0 = peg$currPos;
+    if (input.charCodeAt(peg$currPos) === 34) {
+      s1 = peg$c18;
+      peg$currPos++;
+    } else {
+      s1 = peg$FAILED;
+      if (peg$silentFails === 0) { peg$fail(peg$e23); }
+    }
+    if (s1 !== peg$FAILED) {
+      s2 = [];
+      s3 = input.charAt(peg$currPos);
+      if (peg$r5.test(s3)) {
+        peg$currPos++;
+      } else {
+        s3 = peg$FAILED;
+        if (peg$silentFails === 0) { peg$fail(peg$e24); }
+      }
+      while (s3 !== peg$FAILED) {
+        s2.push(s3);
+        s3 = input.charAt(peg$currPos);
+        if (peg$r5.test(s3)) {
+          peg$currPos++;
+        } else {
+          s3 = peg$FAILED;
+          if (peg$silentFails === 0) { peg$fail(peg$e24); }
+        }
+      }
+      if (input.charCodeAt(peg$currPos) === 34) {
+        s3 = peg$c18;
+        peg$currPos++;
+      } else {
+        s3 = peg$FAILED;
+        if (peg$silentFails === 0) { peg$fail(peg$e23); }
+      }
+      if (s3 !== peg$FAILED) {
+        peg$savedPos = s0;
+        s0 = peg$f19(s2);
+      } else {
+        peg$currPos = s0;
+        s0 = peg$FAILED;
+      }
+    } else {
+      peg$currPos = s0;
+      s0 = peg$FAILED;
+    }
+
+    return s0;
+  }
+
   function peg$parseraise() {
     let s0, s1, s2, s3, s4, s5, s6, s7;
 
     s0 = peg$currPos;
     if (input.charCodeAt(peg$currPos) === 94) {
-      s1 = peg$c18;
+      s1 = peg$c19;
       peg$currPos++;
     } else {
       s1 = peg$FAILED;
-      if (peg$silentFails === 0) { peg$fail(peg$e23); }
+      if (peg$silentFails === 0) { peg$fail(peg$e25); }
     }
     if (s1 !== peg$FAILED) {
       s2 = peg$parse_();
@@ -1317,7 +1411,7 @@ function peg$parse(input, options) {
           s4 = null;
         }
         peg$savedPos = s0;
-        s0 = peg$f18(s3, s4);
+        s0 = peg$f20(s3, s4);
       } else {
         peg$currPos = s0;
         s0 = peg$FAILED;
@@ -1339,11 +1433,11 @@ function peg$parse(input, options) {
     s2 = peg$parsecomment();
     if (s2 === peg$FAILED) {
       s2 = input.charAt(peg$currPos);
-      if (peg$r5.test(s2)) {
+      if (peg$r6.test(s2)) {
         peg$currPos++;
       } else {
         s2 = peg$FAILED;
-        if (peg$silentFails === 0) { peg$fail(peg$e24); }
+        if (peg$silentFails === 0) { peg$fail(peg$e26); }
       }
     }
     while (s2 !== peg$FAILED) {
@@ -1351,16 +1445,16 @@ function peg$parse(input, options) {
       s2 = peg$parsecomment();
       if (s2 === peg$FAILED) {
         s2 = input.charAt(peg$currPos);
-        if (peg$r5.test(s2)) {
+        if (peg$r6.test(s2)) {
           peg$currPos++;
         } else {
           s2 = peg$FAILED;
-          if (peg$silentFails === 0) { peg$fail(peg$e24); }
+          if (peg$silentFails === 0) { peg$fail(peg$e26); }
         }
       }
     }
     peg$savedPos = s0;
-    s1 = peg$f19();
+    s1 = peg$f21();
     s0 = s1;
     peg$silentFails--;
 
@@ -1371,12 +1465,12 @@ function peg$parse(input, options) {
     let s0, s1, s2, s3, s4, s5, s6;
 
     s0 = peg$currPos;
-    if (input.substr(peg$currPos, 2) === peg$c19) {
+    if (input.substr(peg$currPos, 2) === peg$c20) {
-      s1 = peg$c19;
+      s1 = peg$c20;
       peg$currPos += 2;
     } else {
       s1 = peg$FAILED;
-      if (peg$silentFails === 0) { peg$fail(peg$e25); }
+      if (peg$silentFails === 0) { peg$fail(peg$e27); }
     }
     if (s1 !== peg$FAILED) {
       s2 = peg$parse_();
@@ -1387,7 +1481,7 @@ function peg$parse(input, options) {
           peg$currPos++;
         } else {
           s4 = peg$FAILED;
-          if (peg$silentFails === 0) { peg$fail(peg$e26); }
+          if (peg$silentFails === 0) { peg$fail(peg$e28); }
         }
         while (s4 !== peg$FAILED) {
           s3.push(s4);
@@ -1396,17 +1490,17 @@ function peg$parse(input, options) {
             peg$currPos++;
           } else {
             s4 = peg$FAILED;
-            if (peg$silentFails === 0) { peg$fail(peg$e26); }
+            if (peg$silentFails === 0) { peg$fail(peg$e28); }
           }
         }
         s4 = peg$parse_();
         if (s4 !== peg$FAILED) {
           if (input.charCodeAt(peg$currPos) === 10) {
-            s5 = peg$c20;
+            s5 = peg$c21;
             peg$currPos++;
           } else {
             s5 = peg$FAILED;
-            if (peg$silentFails === 0) { peg$fail(peg$e27); }
+            if (peg$silentFails === 0) { peg$fail(peg$e29); }
           }
           if (s5 === peg$FAILED) {
             s5 = peg$currPos;
@@ -1416,7 +1510,7 @@ function peg$parse(input, options) {
               peg$currPos++;
             } else {
               s6 = peg$FAILED;
-              if (peg$silentFails === 0) { peg$fail(peg$e26); }
+              if (peg$silentFails === 0) { peg$fail(peg$e28); }
             }
             peg$silentFails--;
             if (s6 === peg$FAILED) {
@@ -1428,7 +1522,7 @@ function peg$parse(input, options) {
           }
           if (s5 !== peg$FAILED) {
             peg$savedPos = s0;
-            s0 = peg$f20(s3);
+            s0 = peg$f22(s3);
           } else {
             peg$currPos = s0;
             s0 = peg$FAILED;

src/statecharts/parser.ts

@@ -173,6 +173,7 @@ export function parseStatechart(state: VisualEditorState): [Statechart, Traceabl
     let parsed: ParsedText;
     try {
       parsed = parseLabel(text.text); // may throw
+      parsed.uid = text.uid;
     } catch (e) {
       if (e instanceof SyntaxError) {
         errors.push({
@@ -180,21 +181,21 @@ export function parseStatechart(state: VisualEditorState): [Statechart, Traceabl
           message: e.message,
           data: e,
         });
-        continue;
+        parsed = {
+          kind: "parserError",
+          uid: text.uid,
+        }
       }
       else {
         throw e;
       }
     }
-    parsed.uid = text.uid;
-    if (parsed.kind === "transitionLabel") {
     const belongsToArrow = findNearestArrow(text.topLeft, state.arrows);
     if (belongsToArrow) {
       const belongsToTransition = uid2Transition.get(belongsToArrow.uid);
       if (belongsToTransition) {
-          // parse as transition label
         belongsToTransition.label.push(parsed);
-
+        if (parsed.kind === "transitionLabel") {
           // collect events
           // triggers
           if (parsed.trigger.kind === "event") {
@@ -210,6 +211,10 @@ export function parseStatechart(state: VisualEditorState): [Statechart, Traceabl
             belongsToTransition.src.timers.push(parsed.trigger.durationMs);
             belongsToTransition.src.timers.sort();
           }
+          else if (["entry", "exit"].includes(parsed.trigger.kind)) {
+            errors.push({shapeUid: text.uid, message: "entry/exit trigger not allowed on transitions"});
+          }
+
           // // raise-actions
           // for (const action of parsed.actions) {
           //   if (action.kind === "raise") {
@@ -224,15 +229,14 @@ export function parseStatechart(state: VisualEditorState): [Statechart, Traceabl
           // }
 
           // collect variables
-          variables = variables
+          variables = variables.union(findVariables(parsed.guard));
-            .union(findVariables(parsed.guard));
           for (const action of parsed.actions) {
             variables = variables.union(findVariablesAction(action));
           }
         }
-        continue;
       }
     }
+    else {
       // text does not belong to transition...
       // so it belongs to a rountangle (a state)
       const rountangle = findRountangle(text.topLeft, state.rountangles);
@@ -260,6 +264,7 @@ export function parseStatechart(state: VisualEditorState): [Statechart, Traceabl
         belongsToState.comments.push([text.uid, parsed.text]);
       }
     }
+  }
 
   for (const transition of uid2Transition.values()) {
     if (transition.label.length === 0) {

src/statecharts/runtime_types.ts

@@ -17,29 +17,94 @@ export type TimerElapseEvent = {
 
 export type Mode = Set<string>; // set of active states
 
-export type Environment = ReadonlyMap<string, any>; // variable name -> value
+// export type Environment = ReadonlyMap<string, any>; // variable name -> value
 
-// export class Environment {
+export class Environment {
-//   env: Map<string, any>[];
+  scopes: ReadonlyMap<string, any>[]; // array of nested scopes - scope at the back of the array is used first
-//   constructor(env = [new Map()]) {
-//     this.env = env;
-//   }
 
-//   with(key: string, value: any): Environment {
+  constructor(env = [new Map()] as ReadonlyMap<string, any>[]) {
-//     for (let i=0; i<this.env.length; i++) {
+    this.scopes = env;
-//       if (this.env[i].has(key)) {
+  }
-//         return new Environment(this.env.with(i, new Map([
+
-//           ...this.env[i].entries(),
+  pushScope(): Environment {
-//           [key, value],
+    return new Environment([...this.scopes, new Map<string, any>()]);
-//         ])));
+  }
-//       }
+
-//     }
+  popScope(): Environment {
-//     return new Environment(this.env.with(-1, new Map([
+    return new Environment(this.scopes.slice(0, -1));
-//       ...this.env[this.env.length-1].entries(),
+  }
-//       [key, value],
+
-//     ])));
+  // force creation of a new variable in the current scope, even if a variable with the same name already exists in a surrounding scope
-//   }
+  newVar(key: string, value: any): Environment {
-// }
+    return new Environment(
+      this.scopes.with(
+        this.scopes.length-1,
+        new Map([
+          ...this.scopes[this.scopes.length-1],
+          [key, value],
+        ]),
+      ));
+  }
+
+  // update variable in the innermost scope where it exists, or create it in the current scope if it doesn't exist yet
+  set(key: string, value: any): Environment {
+    for (let i=this.scopes.length-1; i>=0; i--) {
+      const map = this.scopes[i];
+      if (map.has(key)) {
+        return new Environment(this.scopes.with(i, new Map([
+          ...map.entries(),
+          [key, value],
+        ])));
+      }
+    }
+    console.log(this.scopes);
+    return new Environment(this.scopes.with(-1, new Map([
+      ...this.scopes[this.scopes.length-1].entries(),
+      [key, value],
+    ])));
+  }
+
+  // lookup variable, starting in the currrent (= innermost) scope, then looking into surrounding scopes until found.
+  get(key: string): any {
+    for (let i=this.scopes.length-1; i>=0; i--) {
+      const map = this.scopes[i];
+      const found = map.get(key);
+      if (found !== undefined) {
+        return found;
+      }
+    }
+  }
+
+  transform<T>(key: string, upd: (old:T) => T, defaultVal: T): Environment {
+    const old = this.get(key) || defaultVal;
+    return this.set(key, upd(old));
+  }
+
+  *entries() {
+    const visited = new Set();
+    for (let i=this.scopes.length-1; i>=0; i--) {
+      const map = this.scopes[i];
+      for (const [key, value] of map.entries()) {
+        if (!visited.has(key)) {
+          yield [key, value];
+          visited.add(key);
+        }
+      }
+    }
+  }
+}
+
+// console.log('env...');
+// let env = new Environment();
+// env = env.set("a", 1);
+// env = env.set("b", 2);
+// env = env.pushScope();
+// console.log(env.get("a")); // 1
+// env = env.newVar("a", 99);
+// console.log(env.get("a")); // 99
+// env = env.popScope();
+// console.log(env.get("a")); // 1
+// console.log('end env...');
 
 export type RT_Statechart = {
   mode: Mode;

src/statecharts/transition_label.grammar

@@ -93,13 +93,21 @@ product = atom:atom rest:((_ ("*" / "/") _) product)? {
     };
 }
 
-atom = nested / literal / ref
+atom = fnCall / nested / literal / ref
 
 nested = "(" _ expr:expr _ ")" {
 	return expr;
 }
 
-literal = value:(number / boolean) {
+fnCall = fn:ref param:nested {
+	return {
+    	kind: "call",
+        fn,
+        param,
+    };
+}
+
+literal = value:(number / boolean / string) {
 	return {kind: "literal", value}
 }
 
@@ -111,6 +119,10 @@ boolean = ("true" / "false") {
 	return text() === "true";
 }
 
+string = '"' str:([^"]*) '"' {
+	return str.join('');
+}
+
 raise = "^" _ event:identifier param:("(" expr ")")? {
 	return {kind: "raise", event, param: param ? param[1] : undefined};
 }