sclass JLeftArrowScriptIDE is Swingable {
  settable SimpleLiveValue<S> lvScript = stringLiveValue();
  S sectionTitle = "Left arrow script";
  
  transient CompileResult compileResult;
  transient RSyntaxTextAreaWithSearch taScript;
  transient new Q compileQ;
  transient JLabel lblCompileResult;
  transient JButton btnRun;
  
  visual {
    taScript = liveValueRSyntaxTextArea_bothWays(lvScript);
    awtCalcEvery(taScript.textArea(), 1.0, -> compileQ.add(r compile));
    
    ret jCenteredSection(sectionTitle,
      centerAndSouthWithMargin(
        taScript.visualize(),
        centerAndEastWithMargin(
          lblCompileResult = jlabel(),
          btnRun = jbutton("Run" := rThread runScript))));
  }
  
  bool visible() { ret isShowing(lblCompileResult); }
  
  void compile {
    var script = lvScript!;
    var result = compileResult;
    if (result == null || !eq(result.script, script)) {
      try {
        result = new CompileResult;
        result.script = script;
        result.parser = new GazelleV_LeftArrowScriptParser;
        modifyParser(result.parser);
        result.parsedScript = result.parser.parse(result.script);
        print(result.parsedScript);
      } catch print e {
        result.compileError = e;
      }
      compileResult = result;
      setText(lblCompileResult, compileResult);
      updateRunButtonState();
    }
  }
  
  swappable void updateRunButtonState() {
    setEnabled(btnRun, compileResult != null && compileResult.runnable());
  }
  
  CompileResult freshCompileResult() {
    runInQAndWait(compileQ, r compile);
    ret compileResult;
  }
  
  GazelleV_LeftArrowScript.Script parsedScript() {
    ret freshCompileResult().parsedScript;
  }

  swappable void runButtonAction {
    runScript();
  }
  
  void runScript {
    //showText_fast_noWrap("Script Error", renderStackTrace(e));
    var result = freshCompileResult();
    if (result.parsedScript != null)
      result.result = okOrError(-> result.parsedScript!);
  }

  class CompileResult {
    S script;
    GazelleV_LeftArrowScriptParser parser;
    Throwable compileError;
    GazelleV_LeftArrowScript.Script parsedScript;
    OKOrError result;

    toString {
      ret compileError != null ? exceptionToStringShorter(compileError) : "Compiled OK";
    }
    
    bool runnable() { ret parsedScript != null; }
  }

  swappable void modifyParser(GazelleV_LeftArrowScriptParser parser) {
    parser.allowTheWorld(mc());
  }
  
  void showRuntimeError(Throwable e) {
    setText(lblCompileResult, exceptionToStringShorter(e));
  }
}