54 lines
1.3 KiB
Scheme
54 lines
1.3 KiB
Scheme
;;;
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;;; Time-stamp: <2008-06-19 21:13:49 noel>
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;;;
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;;; Copyright (C) 2005 by Noel Welsh.
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;;;
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;;; This library is free software; you can redistribute it
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;;; and/or modify it under the terms of the GNU Lesser
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;;; General Public License as published by the Free Software
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;;; Foundation; either version 2.1 of the License, or (at
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;;; your option) any later version.
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;;; This library is distributed in the hope that it will be
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;;; useful, but WITHOUT ANY WARRANTY; without even the
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;;; implied warranty of MERCHANTABILITY or FITNESS FOR A
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;;; PARTICULAR PURPOSE. See the GNU Lesser General Public
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;;; License for more details.
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;;; You should have received a copy of the GNU Lesser
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;;; General Public License along with this library; if not,
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;;; write to the Free Software Foundation, Inc., 59 Temple
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;;; Place, Suite 330, Boston, MA 02111-1307 USA
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;;; Author: Noel Welsh <noelwelsh@yahoo.com>
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;;
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;;
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;; Commentary:
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#lang scheme/base
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(require "monad.ss")
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(provide (all-defined-out))
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(define (make-empty-hash)
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(make-monad (void) (make-hash)))
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(define (return-hash value)
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(lambda (hash)
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(set-monad-value! hash value)
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hash))
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(define (put key val)
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(lambda (hash)
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(hash-set! (monad-state hash) key val)
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hash))
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(define (get key)
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(lambda (hash)
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(let ((val (hash-ref (monad-state hash) key)))
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(set-monad-value! hash val)
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hash)))
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