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236 lines
9.6 KiB
Scheme
236 lines
9.6 KiB
Scheme
;;;; r4rs.scm --- definitions needed for libguile to be R4RS compliant
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;;;; Jim Blandy <jimb@cyclic.com> --- October 1996
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;;;; Copyright (C) 1996, 1997, 1998, 2000, 2001 Free Software Foundation, Inc.
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;;;;
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;;;; This program is free software; you can redistribute it and/or modify
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;;;; it under the terms of the GNU General Public License as published by
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;;;; the Free Software Foundation; either version 2, or (at your option)
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;;;; any later version.
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;;;;
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;;;; This program 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
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;;;; GNU General Public License for more details.
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;;;;
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;;;; You should have received a copy of the GNU General Public License
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;;;; along with this software; see the file COPYING. If not, write to
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;;;; the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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;;;; Boston, MA 02110-1301 USA
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;;;;
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;;;; As a special exception, the Free Software Foundation gives permission
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;;;; for additional uses of the text contained in its release of GUILE.
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;;;;
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;;;; The exception is that, if you link the GUILE library with other files
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;;;; to produce an executable, this does not by itself cause the
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;;;; resulting executable to be covered by the GNU General Public License.
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;;;; Your use of that executable is in no way restricted on account of
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;;;; linking the GUILE library code into it.
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;;;;
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;;;; This exception does not however invalidate any other reasons why
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;;;; the executable file might be covered by the GNU General Public License.
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;;;;
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;;;; This exception applies only to the code released by the
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;;;; Free Software Foundation under the name GUILE. If you copy
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;;;; code from other Free Software Foundation releases into a copy of
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;;;; GUILE, as the General Public License permits, the exception does
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;;;; not apply to the code that you add in this way. To avoid misleading
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;;;; anyone as to the status of such modified files, you must delete
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;;;; this exception notice from them.
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;;;;
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;;;; If you write modifications of your own for GUILE, it is your choice
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;;;; whether to permit this exception to apply to your modifications.
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;;;; If you do not wish that, delete this exception notice.
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;;;; apply and call-with-current-continuation
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;;; We want these to be tail-recursive, so instead of using primitive
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;;; procedures, we define them as closures in terms of the primitive
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;;; macros @apply and @call-with-current-continuation.
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(set! apply (lambda (fun . args) (@apply fun (apply:nconc2last args))))
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(set-procedure-property! apply 'name 'apply)
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(define (call-with-current-continuation proc)
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(@call-with-current-continuation proc))
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(define (call-with-values producer consumer)
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(@call-with-values producer consumer))
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;;;; Basic Port Code
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;;; Specifically, the parts of the low-level port code that are written in
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;;; Scheme rather than C.
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;;;
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;;; WARNING: the parts of this interface that refer to file ports
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;;; are going away. It would be gone already except that it is used
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;;; "internally" in a few places.
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;;; OPEN_READ, OPEN_WRITE, and OPEN_BOTH are used to request the
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;;; proper mode to open files in.
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;;;
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;;; If we want to support systems that do CRLF->LF translation, like
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;;; Windows, then we should have a symbol in scmconfig.h made visible
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;;; to the Scheme level that we can test here, and autoconf magic to
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;;; #define it when appropriate. Windows will probably just have a
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;;; hand-generated scmconfig.h file.
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(define OPEN_READ "r")
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(define OPEN_WRITE "w")
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(define OPEN_BOTH "r+")
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(define *null-device* "/dev/null")
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(define (open-input-file str)
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"Takes a string naming an existing file and returns an input port
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capable of delivering characters from the file. If the file
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cannot be opened, an error is signalled."
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(open-file str OPEN_READ))
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(define (open-output-file str)
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"Takes a string naming an output file to be created and returns an
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output port capable of writing characters to a new file by that
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name. If the file cannot be opened, an error is signalled. If a
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file with the given name already exists, the effect is unspecified."
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(open-file str OPEN_WRITE))
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(define (open-io-file str)
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"Open file with name STR for both input and output."
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(open-file str OPEN_BOTH))
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(define close-io-port close-port)
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(define (call-with-input-file str proc)
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"PROC should be a procedure of one argument, and STR should be a
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string naming a file. The file must
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already exist. These procedures call PROC
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with one argument: the port obtained by opening the named file for
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input or output. If the file cannot be opened, an error is
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signalled. If the procedure returns, then the port is closed
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automatically and the value yielded by the procedure is returned.
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If the procedure does not return, then the port will not be closed
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automatically unless it is possible to prove that the port will
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never again be used for a read or write operation."
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(let* ((file (open-input-file str))
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(ans (proc file)))
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(close-input-port file)
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ans))
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(define (call-with-output-file str proc)
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"PROC should be a procedure of one argument, and STR should be a
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string naming a file. The behaviour is unspecified if the file
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already exists. These procedures call PROC
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with one argument: the port obtained by opening the named file for
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input or output. If the file cannot be opened, an error is
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signalled. If the procedure returns, then the port is closed
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automatically and the value yielded by the procedure is returned.
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If the procedure does not return, then the port will not be closed
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automatically unless it is possible to prove that the port will
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never again be used for a read or write operation."
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(let* ((file (open-output-file str))
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(ans (proc file)))
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(close-output-port file)
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ans))
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(define (with-input-from-port port thunk)
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(let* ((swaports (lambda () (set! port (set-current-input-port port)))))
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(dynamic-wind swaports thunk swaports)))
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(define (with-output-to-port port thunk)
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(let* ((swaports (lambda () (set! port (set-current-output-port port)))))
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(dynamic-wind swaports thunk swaports)))
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(define (with-error-to-port port thunk)
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(let* ((swaports (lambda () (set! port (set-current-error-port port)))))
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(dynamic-wind swaports thunk swaports)))
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(define (with-input-from-file file thunk)
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"THUNK must be a procedure of no arguments, and FILE must be a
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string naming a file. The file must already exist. The file is opened for
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input, an input port connected to it is made
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the default value returned by `current-input-port',
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and the THUNK is called with no arguments.
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When the THUNK returns, the port is closed and the previous
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default is restored. Returns the value yielded by THUNK. If an
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escape procedure is used to escape from the continuation of these
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procedures, their behavior is implementation dependent."
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(let* ((nport (open-input-file file))
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(ans (with-input-from-port nport thunk)))
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(close-port nport)
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ans))
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(define (with-output-to-file file thunk)
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"THUNK must be a procedure of no arguments, and FILE must be a
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string naming a file. The effect is unspecified if the file already exists.
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The file is opened for output, an output port connected to it is made
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the default value returned by `current-output-port',
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and the THUNK is called with no arguments.
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When the THUNK returns, the port is closed and the previous
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default is restored. Returns the value yielded by THUNK. If an
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escape procedure is used to escape from the continuation of these
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procedures, their behavior is implementation dependent."
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(let* ((nport (open-output-file file))
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(ans (with-output-to-port nport thunk)))
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(close-port nport)
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ans))
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(define (with-error-to-file file thunk)
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"THUNK must be a procedure of no arguments, and FILE must be a
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string naming a file. The effect is unspecified if the file already exists.
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The file is opened for output, an output port connected to it is made
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the default value returned by `current-error-port',
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and the THUNK is called with no arguments.
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When the THUNK returns, the port is closed and the previous
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default is restored. Returns the value yielded by THUNK. If an
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escape procedure is used to escape from the continuation of these
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procedures, their behavior is implementation dependent."
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(let* ((nport (open-output-file file))
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(ans (with-error-to-port nport thunk)))
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(close-port nport)
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ans))
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(define (with-input-from-string string thunk)
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"THUNK must be a procedure of no arguments.
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The test of STRING is opened for
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input, an input port connected to it is made,
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and the THUNK is called with no arguments.
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When the THUNK returns, the port is closed.
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Returns the value yielded by THUNK. If an
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escape procedure is used to escape from the continuation of these
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procedures, their behavior is implementation dependent."
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(call-with-input-string string
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(lambda (p) (with-input-from-port p thunk))))
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(define (with-output-to-string thunk)
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"Calls THUNK and returns its output as a string."
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(call-with-output-string
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(lambda (p) (with-output-to-port p thunk))))
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(define (with-error-to-string thunk)
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"Calls THUNK and returns its error output as a string."
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(call-with-output-string
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(lambda (p) (with-error-to-port p thunk))))
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(define the-eof-object (call-with-input-string "" (lambda (p) (read-char p))))
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;;;; Loading
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(if (not (defined? '%load-verbosely))
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(define %load-verbosely #f))
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(define (assert-load-verbosity v) (set! %load-verbosely v))
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(define (%load-announce file)
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(if %load-verbosely
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(with-output-to-port (current-error-port)
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(lambda ()
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(display ";;; ")
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(display "loading ")
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(display file)
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(newline)
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(force-output)))))
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(set! %load-hook %load-announce)
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(define (load name)
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(start-stack 'load-stack
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(primitive-load name)))
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