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21 lines
619 B
Racket
21 lines
619 B
Racket
#lang br
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(require brag/support racket/contract)
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(define basic-lexer
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(lexer-srcloc
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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 lexeme)]
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[(:or "print" "goto" "end" "+" ":") lexeme]
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[(:+ numeric) (token 'INTEGER (string->number lexeme))]
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[(:or (:seq (:+ numeric) ".")
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(:seq (:* numeric) "." (:+ numeric)))
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(token 'DECIMAL (string->number lexeme))]
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[(from/to "\"" "\"")
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(token 'STRING (trim-ends "\"" lexeme "\""))]))
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(provide
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(contract-out
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[basic-lexer
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(input-port? . -> .
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(or/c eof-object? string? srcloc-token?))])) |