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24 lines
558 B
Racket
24 lines
558 B
Racket
3 years ago
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#lang racket/base
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(require (for-syntax racket/base)
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3 years ago
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yaragg/parser-tools/lex
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(prefix-in : yaragg/parser-tools/lex-sre))
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3 years ago
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(provide epsilon ~
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(rename-out [:* *]
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[:+ +]
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[:? ?]
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[:or :]
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[:& &]
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[:: @]
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[:~ ^]
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[:/ -]))
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(define-lex-trans (epsilon stx)
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(syntax-case stx ()
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[(_) #'""]))
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(define-lex-trans (~ stx)
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(syntax-case stx ()
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[(_ RE) #'(complement RE)]))
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