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83 lines
2.5 KiB
Racket
83 lines
2.5 KiB
Racket
#lang racket/base
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(provide define+provide+safe+match)
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(require racket/match
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(for-syntax racket/base
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racket/syntax
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syntax/parse
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syntax/stx
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version/utils))
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;; (define+provide+safe+match name-id
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;; contract-expr
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;; value-expr
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;; #:match-expander
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;; match-transformer-expr)
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;;
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;; (define+provide+safe+match (head . args)
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;; contract-expr
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;; value-body-expr
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;; ...+
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;; #:match-expander
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;; match-transformer-expr)
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(begin-for-syntax
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;; Identifier -> [Syntax -> Syntax]
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(define ((variable-like-transformer id) stx)
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(cond
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[(identifier? stx)
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; id, but with the source location of stx
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(datum->syntax id (syntax-e id) stx id)]
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[(stx-pair? stx)
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(datum->syntax stx (cons id (stx-cdr stx)) stx stx)])))
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(define-syntax define+provide+safe+match
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(λ (stx)
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(syntax-parse stx
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[(d (head . args)
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contract:expr
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value-body:expr ...+
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#:match-expander match-transformer:expr)
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#:with fn-expr (syntax/loc stx (λ args value-body ...))
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(syntax/loc stx
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(d head contract fn-expr #:match-expander match-transformer))]
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[(_ name:id
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contract:expr
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value:expr
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#:match-expander match-transformer:expr)
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#:with internal-name (generate-temporary #'name)
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#:with contract-name (generate-temporary #'name)
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#:with make-name-match-transformer (generate-temporary #'name)
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#:with [name-for-blame ...]
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(cond [(version<=? "6.8" (version)) #'[#:name-for-blame name]]
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[else #'[]])
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#'(begin
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(define internal-name (let ([name value]) name))
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(begin-for-syntax
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(define (make-name-match-transformer name)
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(with-syntax ([name name]) match-transformer)))
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(define-match-expander name
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(make-name-match-transformer (quote-syntax internal-name))
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(variable-like-transformer (quote-syntax internal-name)))
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(provide name)
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(module+ safe
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(require racket/contract/base)
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(define-module-boundary-contract contract-name internal-name contract
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name-for-blame ...)
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(define-match-expander name
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(make-name-match-transformer (quote-syntax contract-name))
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(variable-like-transformer (quote-syntax contract-name)))
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(provide name)))])))
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