50 lines
1.8 KiB
Scheme
50 lines
1.8 KiB
Scheme
;;; srfi-26.scm --- specializing parameters without currying.
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;; Copyright (C) 2002, 2006 Free Software Foundation, Inc.
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;;
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;; This library is free software; you can redistribute it and/or
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;; modify it under the terms of the GNU Lesser General Public
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;; License as published by the Free Software Foundation; either
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;; version 2.1 of the License, or (at your option) any later version.
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;;
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;; This library is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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;; Lesser General Public License for more details.
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;;
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;; You should have received a copy of the GNU Lesser General Public
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;; License along with this library; if not, write to the Free Software
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;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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(define-module (srfi srfi-26)
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:export (cut cute))
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(cond-expand-provide (current-module) '(srfi-26))
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(define-macro (cut slot . slots)
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(let loop ((slots (cons slot slots))
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(params '())
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(args '()))
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(if (null? slots)
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`(lambda ,(reverse! params) ,(reverse! args))
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(let ((s (car slots))
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(rest (cdr slots)))
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(case s
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((<>)
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(let ((var (gensym)))
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(loop rest (cons var params) (cons var args))))
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((<...>)
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(if (pair? rest)
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(error "<...> not on the end of cut expression"))
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(let ((var (gensym)))
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`(lambda ,(append! (reverse! params) var)
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(apply ,@(reverse! (cons var args))))))
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(else
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(loop rest params (cons s args))))))))
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(define-macro (cute . slots)
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(let ((temp (map (lambda (s) (and (not (memq s '(<> <...>))) (gensym)))
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slots)))
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`(let ,(delq! #f (map (lambda (t s) (and t (list t s))) temp slots))
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(cut ,@(map (lambda (t s) (or t s)) temp slots)))))
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