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beautiful-racket/beautiful-racket-demo/txtadv-demo/tokenizer.rkt

27 lines
1.1 KiB
Racket

#lang br
(require parser-tools/lex parser-tools/lex-sre
brag/support
racket/string)
(provide tokenize)
(define (tokenize input-port)
(define (next-token)
(define get-token
(lexer
[(eof) eof]
[(union
(seq "/*" (complement (seq any-string "*/" any-string)) "*/")
(seq "//" (repetition 1 +inf.0 (char-complement #\newline)) #\newline))
(token 'COMMENT lexeme #:skip? #t)]
[(union #\tab #\space #\newline) (get-token input-port)]
[(repetition 1 +inf.0 (union upper-case (char-set "="))) lexeme]
[(seq "\"" (complement (seq any-string "\"" any-string)) "\"") (token 'STRING (string-trim lexeme "\""))]
[(seq "---"
(repetition 1 +inf.0 (union alphabetic numeric punctuation))
"---") (token 'DASHED-NAME (string->symbol (string-trim lexeme "-" #:repeat? #t)))]
[(repetition 1 +inf.0 (union alphabetic numeric (char-set "-!?.#'")))
(token 'ID (read (open-input-string lexeme)))]
[any-char lexeme]))
(get-token input-port))
next-token)