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45 lines
2.1 KiB
Racket
45 lines
2.1 KiB
Racket
#lang racket/base
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(require (for-syntax racket/base) syntax/define)
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(provide (except-out (all-defined-out) values->list))
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(define-syntax-rule (require+provide/safe modname ...)
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(begin
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(begin
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(require modname)
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(provide (all-from-out modname))
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(module+ safe
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(require (submod modname safe))
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(provide (all-from-out (submod modname safe))))) ...))
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(define-syntax (values->list stx)
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(syntax-case stx ()
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[(_ values-expr) #'(call-with-values (λ () values-expr) list)]))
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;; convert calling pattern to form (id contract body-exp)
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;; hoist contract out of lambda-exp entirely
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(define-syntax-rule (lambdafy-with-contract stx)
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(syntax-case stx ()
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[(_ id-exp contract lambda-exp) ; matches exactly three args after `define`
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;; `normalize-definition` can't handle the acceptable `define/contract` pattern of id, contract, lambda exp after the `define`.
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;; so extract the contract, and then put id & lambda-exp back together, and let `normalize-definition` destructure as usual.
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(with-syntax ([(new-id new-lambda-exp) (values->list (normalize-definition #'(_ id-exp lambda-exp) (datum->syntax #'id-exp 'λ) #t #t))])
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#'(new-id contract new-lambda-exp))]
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[(_ id-exp maybe-contract body-exp (... ...)) ; matches two, or four or more
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(with-syntax ([(id (lambda args contract body-exp (... ...))) (values->list (normalize-definition stx (datum->syntax #'id-exp 'λ) #t #t))])
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;; because the macro provides the `lambda` below, it takes the local srcloc by default
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;; so `syntax/loc` applies the original srcloc (associated with args and body-exp)
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#`(id contract #,(syntax/loc stx (lambda args body-exp (... ...)))))]
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[else ; matches zero or one arugments
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(error 'define-macro "not enough arguments")]))
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;; convert calling pattern to form (id body-exp)
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(define-syntax-rule (lambdafy stx)
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(with-syntax ([(id lambda-exp) (let-values ([(id-stx body-exp-stx) (normalize-definition stx (datum->syntax stx 'λ) #t #t)])
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(list id-stx body-exp-stx))])
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#'(id lambda-exp))) |