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;;;; Copyright (c) 2004, Juan Jose Garcia-Ripoll
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;;;; This program is free software; you can redistribute it and/or
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;;;; modify it under the terms of the GNU Library General Public
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;;;; License as published by the Free Software Foundation; either
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;;;; version 2 of the License, or (at your option) any later version.
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;;;; See file '../Copyright' for full details.
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;;;; The CLOS IO library.
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;;; This is the generic function interface for CLOS streams.
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;;; The following is a port of SBCL's implementation of Gray Streams. Minor
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;;; caveats with respect to the proposal are that we rather keep CLOSE,
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;;; STREAM-ELEMENT-TYPE, INPUT-STREAM-P, OUTPUT-STREAM-P and OPEN-STREAM-P
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;;; these as normal functions that call the user extensible EXT:STREAM-{CLOSE,
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;;; ELT-TYPE, INPUT-P, OUTPUT-P, OPEN-P}.
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(defgeneric stream-advance-to-column (stream column)
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"Write enough blank space so that the next character will be
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written at the specified column. Returns true if the operation is
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successful, or NIL if it is not supported for this stream. This is
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intended for use by by PPRINT and FORMAT ~T. The default method uses
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STREAM-LINE-COLUMN and repeated calls to STREAM-WRITE-CHAR with a
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#\SPACE character; it returns NIL if STREAM-LINE-COLUMN returns NIL."))
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(defgeneric stream-clear-input (stream)
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"This is like CL:CLEAR-INPUT, but for Gray streams, returning NIL.
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The default method does nothing."))
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(defgeneric stream-clear-output (stream)
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"This is like CL:CLEAR-OUTPUT, but for Gray streams: clear the given
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output STREAM. The default method does nothing."))
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(defgeneric stream-close (stream &key abort)
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"Close the given STREAM. No more I/O may be performed, but
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inquiries may still be made. If :ABORT is true, an attempt is made
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to clean up the side effects of having created the stream."))
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(defgeneric stream-elt-type (stream)
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"Return a type specifier for the kind of object returned by the
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STREAM. The class FUNDAMENTAL-CHARACTER-STREAM provides a default method
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which returns CHARACTER."))
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(defgeneric stream-finish-output (stream)
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"Attempts to ensure that all output sent to the Stream has reached
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its destination, and only then returns false. Implements
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FINISH-OUTPUT. The default method does nothing."))
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(defgeneric stream-force-output (stream)
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"Attempts to force any buffered output to be sent. Implements
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FORCE-OUTPUT. The default method does nothing."))
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(defgeneric stream-fresh-line (stream)
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"Outputs a new line to the Stream if it is not positioned at the
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begining of a line. Returns T if it output a new line, nil
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otherwise. Used by FRESH-LINE. The default method uses
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STREAM-START-LINE-P and STREAM-TERPRI."))
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(defgeneric stream-input-p (stream)
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(:documentation "Can STREAM perform input operations?"))
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(defgeneric stream-interactive-p (stream)
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(:documentation "Is stream interactive (For instance, a tty)?"))
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(defgeneric stream-line-column (stream)
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"Return the column number where the next character
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will be written, or NIL if that is not meaningful for this stream.
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The first column on a line is numbered 0. This function is used in
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the implementation of PPRINT and the FORMAT ~T directive. For every
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character output stream class that is defined, a method must be
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defined for this function, although it is permissible for it to
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(defgeneric stream-listen (stream)
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"This is used by LISTEN. It returns true or false. The default method uses
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STREAM-READ-CHAR-NO-HANG and STREAM-UNREAD-CHAR. Most streams should
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define their own method since it will usually be trivial and will
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always be more efficient than the default method."))
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(defgeneric stream-open-p (stream)
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"Return true if STREAM is not closed. A default method is provided
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by class FUNDAMENTAL-STREAM which returns true if CLOSE has not been
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called on the stream."))
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(defgeneric stream-output-p (stream)
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(:documentation "Can STREAM perform output operations?"))
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(defgeneric stream-peek-char (stream)
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"This is used to implement PEEK-CHAR; this corresponds to PEEK-TYPE of NIL.
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It returns either a character or :EOF. The default method calls
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STREAM-READ-CHAR and STREAM-UNREAD-CHAR."))
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(defgeneric stream-read-byte (stream)
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"Used by READ-BYTE; returns either an integer, or the symbol :EOF
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if the stream is at end-of-file."))
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(defgeneric stream-read-char (stream)
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"Read one character from the stream. Return either a
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character object, or the symbol :EOF if the stream is at end-of-file.
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Every subclass of FUNDAMENTAL-CHARACTER-INPUT-STREAM must define a
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method for this function."))
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(defgeneric stream-read-char-no-hang (stream)
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"This is used to implement READ-CHAR-NO-HANG. It returns either a
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character, or NIL if no input is currently available, or :EOF if
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end-of-file is reached. The default method provided by
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FUNDAMENTAL-CHARACTER-INPUT-STREAM simply calls STREAM-READ-CHAR; this
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is sufficient for file streams, but interactive streams should define
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(defgeneric stream-read-line (stream)
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"This is used by READ-LINE. A string is returned as the first value. The
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second value is true if the string was terminated by end-of-file
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instead of the end of a line. The default method uses repeated
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calls to STREAM-READ-CHAR."))
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(defgeneric stream-read-sequence (stream seq &optional start end)
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"This is like CL:READ-SEQUENCE, but for Gray streams."))
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(defgeneric stream-start-line-p (stream)
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"Is STREAM known to be positioned at the beginning of a line?
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It is permissible for an implementation to always return
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NIL. This is used in the implementation of FRESH-LINE. Note that
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while a value of 0 from STREAM-LINE-COLUMN also indicates the
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beginning of a line, there are cases where STREAM-START-LINE-P can be
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meaningfully implemented although STREAM-LINE-COLUMN can't be. For
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example, for a window using variable-width characters, the column
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number isn't very meaningful, but the beginning of the line does have
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a clear meaning. The default method for STREAM-START-LINE-P on class
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FUNDAMENTAL-CHARACTER-OUTPUT-STREAM uses STREAM-LINE-COLUMN, so if
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that is defined to return NIL, then a method should be provided for
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either STREAM-START-LINE-P or STREAM-FRESH-LINE."))
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(defgeneric stream-terpri (stream)
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"Writes an end of line, as for TERPRI. Returns NIL. The default
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method does (STREAM-WRITE-CHAR stream #\NEWLINE)."))
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(defgeneric stream-unread-char (stream character)
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"Un-do the last call to STREAM-READ-CHAR, as in UNREAD-CHAR.
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Return NIL. Every subclass of FUNDAMENTAL-CHARACTER-INPUT-STREAM
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must define a method for this function."))
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(defgeneric stream-write-byte (stream integer)
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"Implements WRITE-BYTE; writes the integer to the stream and
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returns the integer as the result."))
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(defgeneric stream-write-char (stream character)
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"Write CHARACTER to STREAM and return CHARACTER. Every
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subclass of FUNDAMENTAL-CHARACTER-OUTPUT-STREAM must have a method
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defined for this function."))
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(defgeneric stream-write-string (stream string &optional start end)
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"This is used by WRITE-STRING. It writes the string to the stream,
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optionally delimited by start and end, which default to 0 and NIL.
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The string argument is returned. The default method provided by
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FUNDAMENTAL-CHARACTER-OUTPUT-STREAM uses repeated calls to
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STREAM-WRITE-CHAR."))
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(defgeneric stream-write-sequence (stream seq &optional start end)
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"This is like CL:WRITE-SEQUENCE, but for Gray streams."))
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;;; Our class hierarchy looks like the one from Gray streams
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;;; character output streams
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;;; A character output stream can be created by defining a class that
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;;; includes FUNDAMENTAL-CHARACTER-OUTPUT-STREAM and defining methods
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;;; for the generic functions below.
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;;; Binary streams can be created by defining a class that includes
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;;; either FUNDAMENTAL-BINARY-INPUT-STREAM or
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;;; FUNDAMENTAL-BINARY-OUTPUT-STREAM (or both) and defining a method
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;;; for STREAM-ELEMENT-TYPE and for one or both of the following
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;;; generic functions.
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(defclass fundamental-stream (standard-object stream)
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((open-p :initform t :accessor stream-open-p))
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(:documentation "the base class for all CLOS streams"))
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(defclass fundamental-input-stream (fundamental-stream) nil)
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(defclass fundamental-output-stream (fundamental-stream) nil)
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(defclass fundamental-character-stream (fundamental-stream) nil)
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(defclass fundamental-binary-stream (fundamental-stream) nil)
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(defclass fundamental-character-input-stream
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(fundamental-input-stream fundamental-character-stream) nil)
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(defclass fundamental-character-output-stream
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(fundamental-output-stream fundamental-character-stream) nil)
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(defclass fundamental-binary-input-stream
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(fundamental-input-stream fundamental-binary-stream) nil)
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(defclass fundamental-binary-output-stream
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(fundamental-output-stream fundamental-binary-stream) nil)
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;;; The following methods constitute default implementations.
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(defun bug-or-error (stream fun)
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(declare (ext::c-local))
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(error "The stream ~S has no suitable method for ~S." stream fun))
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;; STREAM-ADVANCE-TO-COLUMN
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(defmethod stream-advance-to-column ((stream fundamental-character-output-stream)
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(let ((current-column (stream-line-column stream)))
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(let ((fill (- column current-column)))
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(stream-write-char stream #\Space)))
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(defmethod stream-clear-input ((stream fundamental-character-input-stream))
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(defmethod stream-clear-input ((stream stream))
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(bug-or-error stream 'stream-clear-input))
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(defmethod stream-clear-input ((non-stream t))
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(error 'type-error :datum non-stream :expected-type 'stream))
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(defmethod stream-clear-output ((stream fundamental-output-stream))
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(defmethod stream-clear-output ((stream stream))
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(bug-or-error stream 'stream-clear-output))
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(defmethod stream-clear-output ((non-stream t))
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(error 'type-error :datum non-stream :expected-type 'stream))
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(defmethod stream-close ((stream fundamental-stream) &key abort)
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(declare (ignore abort))
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(setf (stream-open-p stream) nil)
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;; STREAM-ELEMENT-TYPE
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(defmethod stream-elt-type ((stream fundamental-character-stream))
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(defmethod stream-elt-type ((stream stream))
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(bug-or-error stream 'stream-elt-type))
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(defmethod stream-elt-type ((non-stream t))
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(error 'type-error :datum non-stream :expected-type 'stream))
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(defmethod stream-finish-output ((stream fundamental-output-stream))
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(defmethod stream-finish-output ((stream stream))
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(bug-or-error stream 'stream-finish-output))
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(defmethod stream-finish-output ((non-stream t))
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(error 'type-error :datum non-stream :expected-type 'stream))
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(defmethod stream-force-output ((stream fundamental-output-stream))
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(defmethod stream-force-output ((stream stream))
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(bug-or-error stream 'stream-force-output))
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(defmethod stream-force-output ((non-stream t))
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(error 'type-error :datum non-stream :expected-type 'stream))
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(defmethod stream-fresh-line ((stream fundamental-character-output-stream))
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(unless (stream-start-line-p stream)
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(stream-terpri stream)
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(defmethod stream-input-p ((stream fundamental-stream))
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(defmethod stream-input-p ((stream fundamental-input-stream))
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(defmethod stream-input-p ((stream stream))
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(bug-or-error stream 'stream-input-p))
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(defmethod stream-input-p ((non-stream t))
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(error 'type-error :datum non-stream :expected-type 'stream))
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;; INTERACTIVE-STREAM-P
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(defmethod stream-interactive-p ((stream stream))
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(bug-or-error stream 'stream-interactive-p))
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(defmethod stream-interactive-p ((non-stream t))
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(error 'type-error :datum non-stream :expected-type 'stream))
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(defmethod stream-line-column ((stream fundamental-character-output-stream))
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(defmethod stream-listen ((stream fundamental-character-input-stream))
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(let ((char (stream-read-char-no-hang stream)))
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(when (characterp char)
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(stream-unread-char stream char)
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(defmethod stream-open-p ((stream fundamental-stream))
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(stream-open-p stream))
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(defmethod stream-open-p ((stream stream))
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(bug-or-error stream 'open-stream-p))
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(defmethod stream-open-p ((non-stream t))
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(error 'type-error :datum non-stream :expected-type 'stream))
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(defmethod stream-output-p ((stream fundamental-stream))
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(defmethod stream-output-p ((stream fundamental-output-stream))
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(defmethod stream-output-p ((stream stream))
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(bug-or-error stream 'stream-output-p))
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(defmethod stream-output-p ((non-stream t))
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(error 'type-error :datum non-stream :expected-type 'stream))
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(defmethod stream-peek-char ((stream fundamental-character-input-stream))
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(let ((char (stream-read-char stream)))
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(unless (eq char :eof)
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(stream-unread-char stream char))
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(defmethod stream-read-byte ((stream stream))
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(bug-or-error stream 'stream-read-byte))
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(defmethod stream-read-byte ((non-stream t))
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(error 'type-error :datum non-stream :expected-type 'stream))
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(defmethod stream-read-char-no-hang ((stream fundamental-character-input-stream))
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(stream-read-char stream))
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(defmethod stream-read-line ((stream fundamental-character-input-stream))
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(let ((res (make-string 80))
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(let ((ch (stream-read-char stream)))
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(return (values (shrink-vector res index) t)))
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(when (char= ch #\newline)
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(return (values (shrink-vector res index) nil)))
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(let ((new (make-string len)))
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(setf (schar res index) ch)
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(defmethod stream-read-sequence ((stream fundamental-character-input-stream)
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&optional (start 0) (end nil))
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(si::do-read-sequence seq stream start end))
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(defmethod stream-read-sequence ((stream fundamental-binary-input-stream)
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&optional (start 0) (end nil))
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(si::do-read-sequence seq stream start end))
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(defmethod stream-start-line-p ((stream fundamental-character-output-stream))
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(eql (stream-line-column stream) 0))
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(defmethod stream-write-byte ((stream stream) integer)
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(bug-or-error stream 'stream-write-byte))
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(defmethod stream-write-byte ((non-stream t) integer)
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(error 'type-error :datum non-stream :expected-type 'stream))
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(defmethod stream-write-sequence ((stream fundamental-character-output-stream)
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&optional (start 0) (end nil))
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(si::do-write-sequence seq stream start end))
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(defmethod stream-write-sequence ((stream fundamental-binary-output-stream)
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&optional (start 0) (end nil))
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(si::do-write-sequence seq stream start end))
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(defmethod stream-write-string ((stream fundamental-character-output-stream)
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string &optional (start 0) end)
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(declare (string string)
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(let ((end (or end (length string))))
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(declare (fixnum end))
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(do ((pos start (1+ pos)))
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(declare (type index pos))
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(stream-write-char stream (aref string pos))))
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(defmethod stream-terpri ((stream fundamental-character-output-stream))
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(stream-write-char stream #\Newline))
added
removed
src/clos/streams.lsp
