todo

一个类似windows

		 TODO JavaScript JavaScript Compiler

* General

  - clean up the compiler source

* Optimizations

  - Improve constant folding: type conversions, expr_multiplicative,
    expr_shift, expr_relational, expr_bitwise, etc.

  - create type-specified virtual machine operands for +, -, *,
    etc. and use them if the types are known.  See JSC$stmt_if_asm()
    for an example.

  - delete_{property,array}	=>	delete_{property,array}
    pop
    const_undefined

* parser.js

  - 7.8 Sharp Variables
  - and more???