program <- ws* rule+ {
`(define (parser input offset) 
	,@(second data)
	(((parse_program)) input offset)) }
rule <- id ws* "<-" ws* ordered-expr-list ws_or_nl* { `(define (,(make-name (first data))) (lambda () ,(fifth data))) }
ordered-expr-list <- expr-list ws* "/" ws* ordered-expr-list  { 
(let ((tail (fifth data)))
	(if (eq? (first tail) 'either)
	    `(either ,(first data) ,@(cdr tail))
	    `(either ,(first data) ,(fifth data))))
} / expr-list { (first data) }
expr-list <- expr (ws+ expr-list)* {
(if (or (null? (second data))
	(and (not (pair? (second data)))
	     (string=? (second data) "")))
    (first data)
    (let ((tail (second (first (second data)))))
      (if (eq? (first tail) 'seq)
	  `(seq ,(first data) ,@(cdr tail))
	  `(seq ,(first data) ,tail))))
}
				 
expr <-  simple-expr "*" { `(many ,(first data)) } / simple-expr "+" { `(many1 ,(first data)) } / simple-expr "?" / simple-expr { (first data) }
simple-expr <- string { (first data) } / action / id { (make-scheme-call-rule-closure (make-name (first data))) } / bracketed-rule  { (first data) } / "!." / "!" expr { `(negate ,(second data)) } / character-class { (first data) } / "." { `(match-any-char 'dummy) } 
bracketed-rule <- "()" / "(" ws* ordered-expr-list ws* ")" { (third data) }

id <- [ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-_]+ { (char-list-to-string (first data)) }
character-class <- "[" (not_right_bracket .)+ "]" { `(match-char ',(fix-escapes (zip-second (second data)))) }
string <- [\"] (![\"] .)* [\"] { `(match-string ,(char-list-to-string (zip-second (second data)))) }
action <- [\{] (![\}] .)* [\}] { `(make-action ,(char-list-to-string (fix-escapes (zip-second (second data))))) }

not_right_bracket <- !"]" 
ws <- [ \t]
nl <- [\n]
ws_or_nl <- ws/nl