該用什麼語言來作語言的解析和轉換呢？

1. 選擇語言，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