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LANGUAGE OS.iso
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t3_1
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xlib.lha
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xlib
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cdecl
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const.scm
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1990-05-31
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;;; C declaration compiler.
;* Copyright 1989 Digital Equipment Corporation
;* All Rights Reserved
;*
;* Permission to use, copy, and modify this software and its documentation is
;* hereby granted only under the following terms and conditions. Both the
;* above copyright notice and this permission notice must appear in all copies
;* of the software, derivative works or modified versions, and any portions
;* thereof, and both notices must appear in supporting documentation.
;*
;* Users of this software agree to the terms and conditions set forth herein,
;* and hereby grant back to Digital a non-exclusive, unrestricted, royalty-free
;* right and license under any changes, enhancements or extensions made to the
;* core functions of the software, including but not limited to those affording
;* compatibility with other hardware or software environments, but excluding
;* applications which incorporate this software. Users further agree to use
;* their best efforts to return to Digital any such changes, enhancements or
;* extensions that they make and inform Digital of noteworthy uses of this
;* software. Correspondence should be provided to Digital at:
;*
;* Director of Licensing
;* Western Research Laboratory
;* Digital Equipment Corporation
;* 100 Hamilton Avenue
;* Palo Alto, California 94301
;*
;* This software may be distributed (but not offered for sale or transferred
;* for compensation) to third parties, provided such third parties agree to
;* abide by the terms and conditions of this notice.
;*
;* THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
;* WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
;* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
;* CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
;* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
;* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
;* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
;* SOFTWARE.
;;; This module compiles constant expressions.
;;;
;;; (const <identifier> <expression>)
;;;
;;; which defines a constant. The expression is evaluated at compile time
;;; and is defined as the following:
;;;
;;; <expression> ::= <constant-symbol>
;;; Scheme-constant
;;; ( Scheme-procedure [ <expression> ... ] )
;;;
;;; When stubs are being generated, this will result in:
;;;
;;; (define <identifier> <value>)
;;;
;;; and when an include file is being generated, it will generate:
;;;
;;; (define-constant <identifier> <value>)
(module const)
;;; During the input phase, the following function is called to process
;;; constant expressions. It will return either the constant or call error
;;; on an error.
(define (INPUT-CONST exp)
(if (and (= (length exp) 3) (symbol? (cadr exp)))
(let ((id (cadr exp)))
(putprop id 'const (cddr exp))
id)
(error 'input-const "Illegal syntax: ~s" exp)))
;;; A constant value is computed by the following expression. Any errors will
;;; be reported by calling error.
(define (CONST-VALUE const)
(cond ((symbol? const)
(let ((value (getprop const 'const)))
(if value
(const-value (car value))
(error 'const-value "Undefined constant: ~s"
const))))
((pair? const)
(let ((proc (top-level-value (car const))))
(if (procedure? proc)
(apply proc (map const-value (cdr const)))
(error 'const-value "Undefined function: ~s"
(car const)))))
(else const)))
;;; Stub declarations are generated by the following function.
(define (EMIT-CONSTS constants define-only const-file-root)
(with-output-to-file
(string-append const-file-root ".t")
(lambda ()
(format #t "(herald ~a)~%~%" const-file-root)
(for-each
(lambda (const)
(unless (memq const define-only)
(format #t "(define-constant ~s ~s)~%"
const (const-value const))))
constants))))