44 lines
1.2 KiB
Scheme
44 lines
1.2 KiB
Scheme
#!r6rs
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;; Copyright (c) 2009 Derick Eddington. All rights reserved.
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;; Licensed under an MIT-style license. My license is in the file
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;; named LICENSE from the original collection this file is distributed
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;; with. If this file is redistributed with some other collection, my
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;; license must also be included.
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(library (srfi private vanish)
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(export
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vanish-define)
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(import
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(rnrs)
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(for (only (rnrs base) begin) (meta -1)))
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#;(define (show stx)
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(display (make-string 60 #\-)) (newline)
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(write (syntax->datum stx)) (newline))
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(define-syntax vanish-define
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(lambda (stx)
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(syntax-case stx ()
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((_ def (vanish ...))
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(for-all identifier? #'(vanish ...))
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#'(make-vanish-define (syntax def) (syntax vanish) ...)))))
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(define (make-vanish-define def . to-vanish)
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(lambda (stx)
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(define (vanish? id)
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(memp (lambda (x) (free-identifier=? id x))
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to-vanish))
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#;(show stx)
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(syntax-case stx ()
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((_ name . _)
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(and (identifier? #'name)
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(vanish? #'name))
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#'(begin))
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((_ (name . _) . _)
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(and (identifier? #'name)
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(vanish? #'name))
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#'(begin))
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((_ . r)
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(cons def #'r)))))
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)
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