code: function CommentEventGenerator(originalEventGenerator, sourceCode) {
  		this.original = originalEventGenerator;
  		this.emitter = originalEventGenerator.emitter;
  		this.sourceCode = sourceCode;
  		this.commentLocsEnter = [];
  		this.commentLocsExit = [];
  	}
docs: ------------------------------------------------------------------------------ Public Interface ------------------------------------------------------------------------------ 
  The event generator for comments.
  This is the decorator pattern.
  This generates events of comments before/after events which are generated the original generator.
  
  @param {EventGenerator} originalEventGenerator - An event generator which is the decoration target.
  @param {SourceCode} sourceCode - A source code which has comments.
  @returns {CommentEventGenerator} new instance.