define parser

[dannypsnl]

Two options

1. macro: define-parser
2. preference subform for define-language like define-language L0 #:with parser

The result function should be able to convert s-expression into language structures.

Draft:

(define-language arith
  #:with-parser
  (terminals (Number (n)))
  (Expr (e) 
        ,n
        (+ ,e ,e))

(parse-arith '(+ (+ 1 2) 3))
;=> (arith:Expr:+ (arith:Expr:+ 1 2) 3)