You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
19 lines
622 B
Racket
19 lines
622 B
Racket
#lang br
|
|
(require parser-tools/lex
|
|
(prefix-in : parser-tools/lex-sre)
|
|
brag/support)
|
|
(provide (all-defined-out))
|
|
|
|
(define basic-lexer
|
|
(lexer-srcloc
|
|
[(eof) eof]
|
|
[whitespace (token lexeme #:skip? #t)]
|
|
[(from/to "rem" "\n") (token 'REM (string-downcase lexeme))]
|
|
[(:or "print" "goto" "end") (token (string-downcase lexeme)
|
|
(string-downcase lexeme))]
|
|
[(:+ numeric) (token 'NUMBER (string->number lexeme))]
|
|
[(from/to "\"" "\"") (token 'STRING (trim-ends "\"" lexeme "\""))]))
|
|
|
|
(define (tokenize ip)
|
|
(port-count-lines! ip)
|
|
(λ () (basic-lexer ip))) |