该用什么语言来做语言的解析和转换呢？

1. 选择语言，用 racket Perl in same time
2. the syntax of grammar use BNF
3. parser of BNF use what

BNF and Regexp use Lisp to descripe.

(regexp \d+ :id)
(grammar :id (regexp )
)
use racket descripe grammar