babel-core/lib/acorn/src/tokencontext.js

Turn ES6 code into readable vanilla ES5 with source maps

"use strict";

var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };

exports.__esModule = true;
// The algorithm used to determine whether a regexp can appear at a
// given point in the program is loosely based on sweet.js' approach.
// See https://github.com/mozilla/sweet.js/wiki/design

var Parser = require("./state").Parser;

var tt = require("./tokentype").types;

var lineBreak = require("./whitespace").lineBreak;

var TokContext = exports.TokContext = function TokContext(token, isExpr, preserveSpace, override) {
  _classCallCheck(this, TokContext);

  this.token = token;
  this.isExpr = isExpr;
  this.preserveSpace = preserveSpace;
  this.override = override;
};

var types = {
  b_stat: new TokContext("{", false),
  b_expr: new TokContext("{", true),
  b_tmpl: new TokContext("${", true),
  p_stat: new TokContext("(", false),
  p_expr: new TokContext("(", true),
  q_tmpl: new TokContext("`", true, true, function (p) {
    return p.readTmplToken();
  }),
  f_expr: new TokContext("function", true)
};

exports.types = types;
var pp = Parser.prototype;

pp.initialContext = function () {
  return [types.b_stat];
};

pp.braceIsBlock = function (prevType) {
  var parent = undefined;
  if (prevType === tt.colon && (parent = this.curContext()).token == "{") return !parent.isExpr;
  if (prevType === tt._return) return lineBreak.test(this.input.slice(this.lastTokEnd, this.start));
  if (prevType === tt._else || prevType === tt.semi || prevType === tt.eof) return true;
  if (prevType == tt.braceL) return this.curContext() === types.b_stat;
  return !this.exprAllowed;
};

pp.updateContext = function (prevType) {
  var update = undefined,
      type = this.type;
  if (type.keyword && prevType == tt.dot) this.exprAllowed = false;else if (update = type.updateContext) update.call(this, prevType);else this.exprAllowed = type.beforeExpr;
};

// Token-specific context update code

tt.parenR.updateContext = tt.braceR.updateContext = function () {
  if (this.context.length == 1) {
    this.exprAllowed = true;
    return;
  }
  var out = this.context.pop();
  if (out === types.b_stat && this.curContext() === types.f_expr) {
    this.context.pop();
    this.exprAllowed = false;
  } else if (out === types.b_tmpl) {
    this.exprAllowed = true;
  } else {
    this.exprAllowed = !out.isExpr;
  }
};

tt.braceL.updateContext = function (prevType) {
  this.context.push(this.braceIsBlock(prevType) ? types.b_stat : types.b_expr);
  this.exprAllowed = true;
};

tt.dollarBraceL.updateContext = function () {
  this.context.push(types.b_tmpl);
  this.exprAllowed = true;
};

tt.parenL.updateContext = function (prevType) {
  var statementParens = prevType === tt._if || prevType === tt._for || prevType === tt._with || prevType === tt._while;
  this.context.push(statementParens ? types.p_stat : types.p_expr);
  this.exprAllowed = true;
};

tt.incDec.updateContext = function () {};

tt._function.updateContext = function () {
  if (this.curContext() !== types.b_stat) this.context.push(types.f_expr);
  this.exprAllowed = false;
};

tt.backQuote.updateContext = function () {
  if (this.curContext() === types.q_tmpl) this.context.pop();else this.context.push(types.q_tmpl);
  this.exprAllowed = false;
};

// tokExprAllowed stays unchanged