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#lang racket/base
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(require (for-syntax racket/base syntax/parse) br/macro)
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(provide (all-defined-out) (all-from-out br/macro))
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(define-syntax (define-cases stx)
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(syntax-parse stx
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#:literals (syntax)
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[(_ id:id)
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(raise-syntax-error 'define-cases "no cases given" (syntax->datum #'id))]
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[(_ id:id [(_ . pat-args:expr) . body:expr] ...)
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#'(define id
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(case-lambda
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[pat-args . body] ...
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[rest-pat (apply raise-arity-error 'id (normalize-arity (map length '(pat-args ...))) rest-pat)]))]
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[else (raise-syntax-error
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'define-cases
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"no matching case for calling pattern"
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(syntax->datum stx))]))
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