Switch JsDuck::Esprima over to ExecJS.

require 'v8'

require 'execjs'

require 'json'

require 'singleton'

module JsDuck

  # Runs Esprima.js through V8.

  # Runs Esprima.js through execjs (this will select any available

  # JavaScript runtime - preferably therubyracer on MRI and JScript

  # on Windows).

  #

  # Initialized as singleton to avoid loading the esprima.js more

  # than once - otherwise performace will severely suffer.

    include Singleton

    def initialize

      @v8 = V8::Context.new

      esprima = File.dirname(File.dirname(File.dirname(File.expand_path(__FILE__))))+"/esprima/esprima.js";

      @v8.load(esprima)

      esprima_path = File.dirname(File.dirname(File.dirname(File.expand_path(__FILE__))))+"/esprima/esprima.js";

      esprima = IO.read(esprima_path)

      helper = "function runEsprima(js) { return JSON.stringify(esprima.parse(js, {comment: true, range: true, raw: true})); }"

      @context = ExecJS.compile(esprima + "\n\n" + helper)

    end

    # Parses JavaScript source code using Esprima.js

    #

    # Returns the resulting AST

    def parse(input)

      @v8['js'] = input

      json = @v8.eval("JSON.stringify(esprima.parse(js, {comment: true, range: true, raw: true}))")

      json = @context.call("runEsprima", input)

      return JSON.parse(json, :max_nesting => false)

    end