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32 lines
1.2 KiB
Racket
32 lines
1.2 KiB
Racket
#lang br
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(require brag/support)
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(define-lex-abbrev digits (:+ (char-set "0123456789")))
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(define-lex-abbrev reserved-terms (:or "print" "goto" "end" "+" ":" ";" "let" "=" "input" "-" "*" "/" "^" "mod" "(" ")" "if" "then" "else" "<" ">" "<>" "and" "or" "not" "gosub" "return" "for" "to" "step" "next" "def" "," "import" "export"))
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(define-lex-abbrev racket-id-kapu
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(:or whitespace (char-set "()[]{}\",'`;#|\\")))
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(define basic-lexer
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(lexer-srcloc
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["\n" (token 'NEWLINE lexeme)]
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[whitespace (token lexeme #:skip? #t)]
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[(from/stop-before "rem" "\n") (token 'REM lexeme)]
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[(:seq "[" (:+ (:~ racket-id-kapu)) "]")
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(token 'RACKET-ID
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(string->symbol (trim-ends "[" lexeme "]")))]
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[reserved-terms (token lexeme lexeme)]
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[(:seq alphabetic (:* (:or alphabetic numeric "$")))
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(token 'ID (string->symbol lexeme))]
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[digits (token 'INTEGER (string->number lexeme))]
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[(:or (:seq (:? digits) "." digits)
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(:seq digits "."))
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(token 'DECIMAL (string->number lexeme))]
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[(:or (from/to "\"" "\"") (from/to "'" "'"))
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(token 'STRING
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(substring lexeme
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1 (sub1 (string-length lexeme))))]))
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(provide basic-lexer)
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