parseCatch_() {
    let start = this.getTreeStartLocation_();
    let catchBlock;
    this.eat_(CATCH);
    this.eat_(OPEN_PAREN);
    let binding;
    if (this.peekPattern_(peekType()))
      binding = this.parseBindingPattern_();
    else
      binding = this.parseBindingIdentifier_();
    this.eat_(CLOSE_PAREN);
    let catchBody = this.parseBlock_();
    catchBlock = new Catch(this.getTreeLocation_(start), binding,
                           catchBody);
    return catchBlock;
  }
Catch :
  catch ( CatchParameter ) Block

CatchParameter :
  BindingIdentifier
  BindingPattern

@return {ParseTree}
@private