events.js

'use strict';

let nextEventId = 0;

class Event {
  constructor(sourceLoc, env) {
    this.id = nextEventId++;
    this.sourceLoc = sourceLoc;
    this.env = env;
    this.children = [];
  }

  toMicroVizString() {
    throw new Error('abstract method!');
  }

  _valueString(v) {
    if (typeof v === 'function') {
      return '{function}';
    } else if (v === undefined) {
      return 'undefined';
    } else {
      return JSON.stringify(v);
    }
  }

  subsumes(that) {
    return false;
  }
}

class ProgramEvent extends Event {
  constructor(sourceLoc) {
    super(sourceLoc, null);
    // also: activationEnv
  }
}

class SendEvent extends Event {
  constructor(sourceLoc, env, recv, selector, args) {
    super(sourceLoc, env);
    this.recv = recv;
    this.selector = selector;
    this.args = args;
    // also: activationEnv, returnValue
  }
}

class VarDeclEvent extends Event {
  constructor(sourceLoc, env, name, value) {
    super(sourceLoc, env);
    this.name = name;
    this.value = value;
  }

  toMicroVizString() {
    return this.name + ' = ' + this._valueString(this.value);
  }
}

class VarAssignmentEvent extends Event {
  constructor(sourceLoc, env, declEnv, name, value) {
    super(sourceLoc, env);
    this.declEnv = declEnv;
    this.name = name;
    this.value = value;
  }

  subsumes(that) {
    return (that instanceof VarAssignmentEvent || that instanceof VarDeclEvent) &&
        this.name === that.name && this.declEnv === that.declEnv;
  }

  toMicroVizString() {
    return this.name + ' = ' + this._valueString(this.value);
  }
}

class InstVarAssignmentEvent extends Event {
  constructor(sourceLoc, env, obj, name, value) {
    super(sourceLoc, env);
    this.obj = obj;
    this.name = name;
    this.value = value;
  }

  subsumes(that) {
    return that instanceof InstVarAssignmentEvent &&
        this.receiver === that.receiver && this.name === that.name;
  }

  toMicroVizString() {
    return this._valueString(this.obj) + '.' + this.name + ' = ' + this._valueString(this.value);
  }
}

class InstantiationEvent extends Event {
  // TODO: how should we handle the call to init?
  constructor(sourceLoc, env, _class, args, newInstance) {
    super(sourceLoc, env);
    this.class = _class;
    this.args = args;
    this.newInstance = newInstance;
  }

  toMicroVizString() {
    return 'new ' + this._valueString(this.class) + ' -> ' + this._valueString(this.newInstance);
  }
}

class ReturnEvent extends Event {
  constructor(sourceLoc, env, value) {
    super(sourceLoc, env);
    this.value = value;
  }

  toMicroVizString() {
    return 'return ' + this._valueString(this.value);
  }
}