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19 lines
623 B
Racket
19 lines
623 B
Racket
#lang br
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(require parser-tools/lex
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(prefix-in : parser-tools/lex-sre)
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brag/support)
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(provide (all-defined-out))
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(define basic-lexer
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(lexer-src-pos
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[(eof) eof]
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[whitespace (token lexeme #:skip? #t)]
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[(from/to "rem" "\n") (token 'REM (string-downcase lexeme))]
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[(:or "print" "goto" "end") (token (string-downcase lexeme)
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(string-downcase lexeme))]
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[(:+ numeric) (token 'NUMBER (string->number lexeme))]
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[(from/to "\"" "\"") (token 'STRING (trim-ends "\"" lexeme "\""))]))
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(define (tokenize ip)
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(port-count-lines! ip)
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(λ () (basic-lexer ip))) |