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brag/parser-tools/yacc-to-scheme.rkt

131 lines
4.0 KiB
Racket

#lang racket/base
(require yaragg/parser-tools/lex
(prefix-in : yaragg/parser-tools/lex-sre)
yaragg/parser-tools/yacc
syntax/readerr
racket/list)
(provide trans)
(define match-double-string
(lexer
[(:+ (:~ #\" #\\)) (append (string->list lexeme)
(match-double-string input-port))]
[(:: #\\ any-char) (cons (string-ref lexeme 1) (match-double-string input-port))]
[#\" null]))
(define match-single-string
(lexer
[(:+ (:~ #\' #\\)) (append (string->list lexeme)
(match-single-string input-port))]
[(:: #\\ any-char) (cons (string-ref lexeme 1) (match-single-string input-port))]
[#\' null]))
(define-lex-abbrevs
[letter (:or (:/ "a" "z") (:/ "A" "Z"))]
[digit (:/ "0" "9")]
[initial (:or letter (char-set "!$%&*/<=>?^_~@"))]
[subsequent (:or initial digit (char-set "+-.@"))]
[comment (:: "/*" (complement (:: any-string "*/" any-string)) "*/")])
(define-empty-tokens x (EOF PIPE |:| SEMI |%%| %prec))
(define-tokens y (SYM STRING))
(define get-token-grammar
(lexer-src-pos
["%%" '|%%|]
[":" (string->symbol lexeme)]
["%prec" (string->symbol lexeme)]
[#\| 'PIPE]
[(:+ (:or #\newline #\tab " " comment (:: "{" (:* (:~ "}")) "}")))
(return-without-pos (get-token-grammar input-port))]
[#\; 'SEMI]
[#\' (token-STRING (string->symbol (list->string (match-single-string input-port))))]
[#\" (token-STRING (string->symbol (list->string (match-double-string input-port))))]
[(:: initial (:* subsequent)) (token-SYM (string->symbol lexeme))]))
(define (parse-grammar enter-term enter-empty-term enter-non-term)
(parser
(tokens x y)
(src-pos)
(error (λ (tok-ok tok-name tok-value start-pos end-pos)
(raise-read-error
(format "Error Parsing YACC grammar at token: ~a with value: ~a" tok-name tok-value)
(file-path)
(position-line start-pos)
(position-col start-pos)
(position-offset start-pos)
(- (position-offset end-pos) (position-offset start-pos)))))
(end |%%|)
(start gram)
(grammar
(gram
((production) (list $1))
((production gram) (cons $1 $2)))
(production
((SYM |:| prods SEMI)
(begin
(enter-non-term $1)
(cons $1 $3))))
(prods
((rhs) (list `(,$1 #f)))
((rhs prec) (list `(,$1 ,$2 #f)))
((rhs PIPE prods) (cons `(,$1 #f) $3))
((rhs prec PIPE prods) (cons `(,$1 ,$2 #f) $4)))
(prec
((%prec SYM)
(begin
(enter-term $2)
(list 'prec $2)))
((%prec STRING)
(begin
(enter-empty-term $2)
(list 'prec $2))))
(rhs
(() null)
((SYM rhs)
(begin
(enter-term $1)
(cons $1 $2)))
((STRING rhs)
(begin
(enter-empty-term $1)
(cons $1 $2)))))))
(define (symbol<? a b)
(string<? (symbol->string a) (symbol->string b)))
(define (trans filename)
(define i (open-input-file filename))
(define terms (make-hasheq))
(define eterms (make-hasheq))
(define nterms (make-hasheq))
(define (enter-term s)
(when (not (hash-ref nterms s (λ () #f)))
(hash-set! terms s #t)))
(define (enter-empty-term s)
(when (not (hash-ref nterms s (λ () #f)))
(hash-set! eterms s #t)))
(define (enter-non-term s)
(hash-remove! terms s)
(hash-remove! eterms s)
(hash-set! nterms s #t))
(port-count-lines! i)
(file-path filename)
(regexp-match "%%" i)
(begin0
(let ([gram ((parse-grammar enter-term enter-empty-term enter-non-term)
(λ ()
(let ((t (get-token-grammar i)))
t)))])
`(begin
(define-tokens t ,(sort (hash-map terms (λ (k v) k)) symbol<?))
(define-empty-tokens et ,(sort (hash-map eterms (λ (k v) k)) symbol<?))
(parser
(start ___)
(end ___)
(error ___)
(tokens t et)
(grammar ,@gram))))
(close-input-port i)))