src/pcl/gray-streams.lisp

   1 ;;;; Gray streams implementation for SBCL, based on the Gray streams
   2 ;;;; implementation for CMU CL, based on the stream-definition-by-user
   3 ;;;; proposal by David N. Gray.
   4
   5 ;;;; This software is part of the SBCL system. See the README file for
   6 ;;;; more information.
   7
   8 ;;;; This software is in the public domain and is provided with
   9 ;;;; absolutely no warranty. See the COPYING and CREDITS files for
  10 ;;;; more information.
  11
  12 (in-package "SB-GRAY")
  13
  14 ;;; BUG-OR-ERROR: because we have extensible streams, wherewith the
  15 ;;; user is responsible for some of the protocol implementation, it's
  16 ;;; not necessarily a bug in SBCL itself if we fall through to one of
  17 ;;; these default methods.
  18 ;;;
  19 ;;; FIXME: there's a lot of similarity in these Gray stream
  20 ;;; implementation generic functions.  All of them could (maybe
  21 ;;; should?) have two default methods: one on STREAM calling
  22 ;;; BUG-OR-ERROR, and one on T signalling a TYPE-ERROR.
  23 (defmacro bug-or-error (stream fun)
  24   `(error
  25     "~@<The stream ~S has no suitable method for ~S, ~
  26      and so has fallen through to this method.  If you think that this is ~
  27      a bug, please report it to the applicable authority (bugs in SBCL itself ~
  28      should go to the mailing lists referenced from ~
  29      <http://www.sbcl.org/>).~@:>"
  30     ,stream ,fun))
  31 \f
  32 (fmakunbound 'stream-element-type)
  33
  34 (defgeneric stream-element-type (stream)
  35   #+sb-doc
  36   (:documentation
  37    "Return a type specifier for the kind of object returned by the
  38   STREAM. The class FUNDAMENTAL-CHARACTER-STREAM provides a default method
  39   which returns CHARACTER."))
  40
  41 (defmethod stream-element-type ((stream ansi-stream))
  42   (ansi-stream-element-type stream))
  43
  44 (defmethod stream-element-type ((stream fundamental-character-stream))
  45   'character)
  46
  47 (defmethod stream-element-type ((stream stream))
  48   (bug-or-error stream 'stream-element-type))
  49
  50 (defmethod stream-element-type ((non-stream t))
  51   (error 'type-error :datum non-stream :expected-type 'stream))
  52 \f
  53 (defgeneric pcl-open-stream-p (stream)
  54   #+sb-doc
  55   (:documentation
  56    "Return true if STREAM is not closed. A default method is provided
  57   by class FUNDAMENTAL-STREAM which returns true if CLOSE has not been
  58   called on the stream."))
  59
  60 (defmethod pcl-open-stream-p ((stream ansi-stream))
  61   (ansi-stream-open-stream-p stream))
  62
  63 (defmethod pcl-open-stream-p ((stream fundamental-stream))
  64   (stream-open-p stream))
  65
  66 (defmethod pcl-open-stream-p ((stream stream))
  67   (bug-or-error stream 'open-stream-p))
  68
  69 (defmethod pcl-open-stream-p ((non-stream t))
  70   (error 'type-error :datum non-stream :expected-type 'stream))
  71
  72 ;;; bootstrapping hack
  73 (pcl-open-stream-p (make-string-output-stream))
  74 (setf (fdefinition 'open-stream-p) #'pcl-open-stream-p)
  75 \f
  76 (defgeneric pcl-close (stream &key abort)
  77   #+sb-doc
  78   (:documentation
  79    "Close the given STREAM. No more I/O may be performed, but
  80   inquiries may still be made. If :ABORT is true, an attempt is made
  81   to clean up the side effects of having created the stream."))
  82
  83 (defmethod pcl-close ((stream ansi-stream) &key abort)
  84   (ansi-stream-close stream abort))
  85
  86 (defmethod pcl-close ((stream fundamental-stream) &key abort)
  87   (declare (ignore abort))
  88   (setf (stream-open-p stream) nil)
  89   t)
  90
  91 (setf (fdefinition 'close) #'pcl-close)
  92 \f
  93 (let ()
  94   (fmakunbound 'input-stream-p)
  95
  96   (defgeneric input-stream-p (stream)
  97     #+sb-doc
  98     (:documentation "Can STREAM perform input operations?"))
  99
 100   (defmethod input-stream-p ((stream ansi-stream))
 101     (ansi-stream-input-stream-p stream))
 102
 103   (defmethod input-stream-p ((stream fundamental-stream))
 104     nil)
 105
 106   (defmethod input-stream-p ((stream fundamental-input-stream))
 107     t)
 108
 109   (defmethod input-stream-p ((stream stream))
 110     (bug-or-error stream 'input-stream-p))
 111
 112   (defmethod input-stream-p ((non-stream t))
 113     (error 'type-error :datum non-stream :expected-type 'stream)))
 114 \f
 115 (let ()
 116   (fmakunbound 'interactive-stream-p)
 117
 118   (defgeneric interactive-stream-p (stream)
 119     #+sb-doc
 120     (:documentation "Is STREAM an interactive stream?"))
 121
 122   (defmethod interactive-stream-p ((stream ansi-stream))
 123     (funcall (ansi-stream-misc stream) stream :interactive-p))
 124
 125   (defmethod interactive-stream-p ((stream fundamental-stream))
 126     nil)
 127
 128   (defmethod interactive-stream-p ((stream stream))
 129     (bug-or-error stream 'interactive-stream-p))
 130
 131   (defmethod interactive-stream-p ((non-stream t))
 132     (error 'type-error :datum non-stream :expected-type 'stream)))
 133 \f
 134 (let ()
 135   (fmakunbound 'output-stream-p)
 136
 137   (defgeneric output-stream-p (stream)
 138     #+sb-doc
 139     (:documentation "Can STREAM perform output operations?"))
 140
 141   (defmethod output-stream-p ((stream ansi-stream))
 142     (ansi-stream-output-stream-p stream))
 143
 144   (defmethod output-stream-p ((stream fundamental-stream))
 145     nil)
 146
 147   (defmethod output-stream-p ((stream fundamental-output-stream))
 148     t)
 149
 150   (defmethod output-stream-p ((stream stream))
 151     (bug-or-error stream 'output-stream-p))
 152
 153   (defmethod output-stream-p ((non-stream t))
 154     (error 'type-error :datum non-stream :expected-type 'stream)))
 155 \f
 156 ;;; character input streams
 157 ;;;
 158 ;;; A character input stream can be created by defining a class that
 159 ;;; includes FUNDAMENTAL-CHARACTER-INPUT-STREAM and defining methods
 160 ;;; for the generic functions below.
 161
 162 (defgeneric stream-read-char (stream)
 163   #+sb-doc
 164   (:documentation
 165    "Read one character from the stream. Return either a
 166   character object, or the symbol :EOF if the stream is at end-of-file.
 167   Every subclass of FUNDAMENTAL-CHARACTER-INPUT-STREAM must define a
 168   method for this function."))
 169
 170 (defgeneric stream-unread-char (stream character)
 171   #+sb-doc
 172   (:documentation
 173    "Un-do the last call to STREAM-READ-CHAR, as in UNREAD-CHAR.
 174   Return NIL. Every subclass of FUNDAMENTAL-CHARACTER-INPUT-STREAM
 175   must define a method for this function."))
 176
 177 (defgeneric stream-read-char-no-hang (stream)
 178   #+sb-doc
 179   (:documentation
 180    "This is used to implement READ-CHAR-NO-HANG. It returns either a
 181   character, or NIL if no input is currently available, or :EOF if
 182   end-of-file is reached. The default method provided by
 183   FUNDAMENTAL-CHARACTER-INPUT-STREAM simply calls STREAM-READ-CHAR; this
 184   is sufficient for file streams, but interactive streams should define
 185   their own method."))
 186
 187 (defmethod stream-read-char-no-hang ((stream fundamental-character-input-stream))
 188   (stream-read-char stream))
 189
 190 (defgeneric stream-peek-char (stream)
 191   #+sb-doc
 192   (:documentation
 193    "This is used to implement PEEK-CHAR; this corresponds to PEEK-TYPE of NIL.
 194   It returns either a character or :EOF. The default method calls
 195   STREAM-READ-CHAR and STREAM-UNREAD-CHAR."))
 196
 197 (defmethod stream-peek-char ((stream fundamental-character-input-stream))
 198   (let ((char (stream-read-char stream)))
 199     (unless (eq char :eof)
 200       (stream-unread-char stream char))
 201     char))
 202
 203 (defgeneric stream-listen (stream)
 204   #+sb-doc
 205   (:documentation
 206    "This is used by LISTEN. It returns true or false. The default method uses
 207   STREAM-READ-CHAR-NO-HANG and STREAM-UNREAD-CHAR. Most streams should
 208   define their own method since it will usually be trivial and will
 209   always be more efficient than the default method."))
 210
 211 (defmethod stream-listen ((stream fundamental-character-input-stream))
 212   (let ((char (stream-read-char-no-hang stream)))
 213     (when (characterp char)
 214       (stream-unread-char stream char)
 215       t)))
 216
 217 (defgeneric stream-read-line (stream)
 218   #+sb-doc
 219   (:documentation
 220    "This is used by READ-LINE. A string is returned as the first value. The
 221   second value is true if the string was terminated by end-of-file
 222   instead of the end of a line. The default method uses repeated
 223   calls to STREAM-READ-CHAR."))
 224
 225 (defmethod stream-read-line ((stream fundamental-character-input-stream))
 226   (let ((res (make-string 80))
 227         (len 80)
 228         (index 0))
 229     (loop
 230      (let ((ch (stream-read-char stream)))
 231        (cond ((eq ch :eof)
 232               (return (values (%shrink-vector res index) t)))
 233              (t
 234               (when (char= ch #\newline)
 235                 (return (values (%shrink-vector res index) nil)))
 236               (when (= index len)
 237                 (setq len (* len 2))
 238                 (let ((new (make-string len)))
 239                   (replace new res)
 240                   (setq res new)))
 241               (setf (schar res index) ch)
 242               (incf index)))))))
 243
 244 (defgeneric stream-clear-input (stream)
 245   #+sb-doc
 246   (:documentation
 247    "This is like CL:CLEAR-INPUT, but for Gray streams, returning NIL.
 248   The default method does nothing."))
 249
 250 (defmethod stream-clear-input ((stream fundamental-character-input-stream))
 251   nil)
 252 (defmethod stream-clear-input ((stream stream))
 253   (bug-or-error stream 'stream-clear-input))
 254 (defmethod stream-clear-input ((non-stream t))
 255   (error 'type-error :datum non-stream :expected-type 'stream))
 256
 257 (defgeneric stream-read-sequence (stream seq &optional start end)
 258   #+sb-doc
 259   (:documentation
 260    "This is like CL:READ-SEQUENCE, but for Gray streams."))
 261
 262 ;;; Destructively modify SEQ by reading elements from STREAM. That
 263 ;;; part of SEQ bounded by START and END is destructively modified by
 264 ;;; copying successive elements into it from STREAM. If the end of
 265 ;;; file for STREAM is reached before copying all elements of the
 266 ;;; subsequence, then the extra elements near the end of sequence are
 267 ;;; not updated, and the index of the next element is returned.
 268 (defun basic-io-type-stream-read-sequence (stream seq start end read-fun)
 269   (declare (type sequence seq)
 270            (type stream stream)
 271            (type index start)
 272            (type sequence-end end)
 273            (type function read-fun)
 274            (values index))
 275   (let ((end (or end (length seq))))
 276     (declare (type index end))
 277     (etypecase seq
 278       (list
 279         (do ((rem (nthcdr start seq) (rest rem))
 280              (i start (1+ i)))
 281             ((or (endp rem) (>= i end)) i)
 282           (declare (type list rem)
 283                    (type index i))
 284           (let ((el (funcall read-fun stream)))
 285             (when (eq el :eof)
 286               (return i))
 287             (setf (first rem) el))))
 288       (vector
 289         (with-array-data ((data seq) (offset-start start) (offset-end end))
 290           (do ((i offset-start (1+ i)))
 291               ((>= i offset-end) end)
 292             (declare (type index i))
 293             (let ((el (funcall read-fun stream)))
 294               (when (eq el :eof)
 295                 (return (+ start (- i offset-start))))
 296               (setf (aref data i) el))))))))
 297
 298 (defmethod stream-read-sequence ((stream fundamental-character-input-stream)
 299                                  (seq sequence)
 300                                  &optional (start 0) (end nil))
 301   (basic-io-type-stream-read-sequence stream seq start end
 302                                       #'stream-read-char))
 303
 304 (defmethod stream-read-sequence ((stream fundamental-binary-input-stream)
 305                                  (seq sequence)
 306                                  &optional (start 0) (end nil))
 307   (basic-io-type-stream-read-sequence stream seq start end
 308                                       #'stream-read-byte))
 309
 310 \f
 311 ;;; character output streams
 312 ;;;
 313 ;;; A character output stream can be created by defining a class that
 314 ;;; includes FUNDAMENTAL-CHARACTER-OUTPUT-STREAM and defining methods
 315 ;;; for the generic functions below.
 316
 317 (defgeneric stream-write-char (stream character)
 318   #+sb-doc
 319   (:documentation
 320    "Write CHARACTER to STREAM and return CHARACTER. Every
 321   subclass of FUNDAMENTAL-CHARACTER-OUTPUT-STREAM must have a method
 322   defined for this function."))
 323
 324 (defgeneric stream-line-column (stream)
 325   #+sb-doc
 326   (:documentation
 327    "Return the column number where the next character
 328   will be written, or NIL if that is not meaningful for this stream.
 329   The first column on a line is numbered 0. This function is used in
 330   the implementation of PPRINT and the FORMAT ~T directive. For every
 331   character output stream class that is defined, a method must be
 332   defined for this function, although it is permissible for it to
 333   always return NIL."))
 334
 335 (defmethod stream-line-column ((stream fundamental-character-output-stream))
 336    nil)
 337
 338 ;;; STREAM-LINE-LENGTH is a CMU CL extension to Gray streams.
 339 ;;; FIXME: Should we support it? Probably not..
 340 (defgeneric stream-line-length (stream)
 341   #+sb-doc
 342   (:documentation "Return the stream line length or NIL."))
 343
 344 (defmethod stream-line-length ((stream fundamental-character-output-stream))
 345   nil)
 346
 347 (defgeneric stream-start-line-p (stream)
 348   #+sb-doc
 349   (:documentation
 350    "Is STREAM known to be positioned at the beginning of a line?
 351   It is permissible for an implementation to always return
 352   NIL. This is used in the implementation of FRESH-LINE. Note that
 353   while a value of 0 from STREAM-LINE-COLUMN also indicates the
 354   beginning of a line, there are cases where STREAM-START-LINE-P can be
 355   meaningfully implemented although STREAM-LINE-COLUMN can't be. For
 356   example, for a window using variable-width characters, the column
 357   number isn't very meaningful, but the beginning of the line does have
 358   a clear meaning. The default method for STREAM-START-LINE-P on class
 359   FUNDAMENTAL-CHARACTER-OUTPUT-STREAM uses STREAM-LINE-COLUMN, so if
 360   that is defined to return NIL, then a method should be provided for
 361   either STREAM-START-LINE-P or STREAM-FRESH-LINE."))
 362
 363 (defmethod stream-start-line-p ((stream fundamental-character-output-stream))
 364   (eql (stream-line-column stream) 0))
 365
 366 (defgeneric stream-write-string (stream string &optional start end)
 367   #+sb-doc
 368   (:documentation
 369    "This is used by WRITE-STRING. It writes the string to the stream,
 370   optionally delimited by start and end, which default to 0 and NIL.
 371   The string argument is returned. The default method provided by
 372   FUNDAMENTAL-CHARACTER-OUTPUT-STREAM uses repeated calls to
 373   STREAM-WRITE-CHAR."))
 374
 375 (defmethod stream-write-string ((stream fundamental-character-output-stream)
 376                                 string &optional (start 0) end)
 377   (declare (string string)
 378            (fixnum start))
 379   (let ((end (or end (length string))))
 380     (declare (fixnum end))
 381     (do ((pos start (1+ pos)))
 382         ((>= pos end))
 383       (declare (type index pos))
 384       (stream-write-char stream (aref string pos))))
 385   string)
 386
 387 (defgeneric stream-terpri (stream)
 388   #+sb-doc
 389   (:documentation
 390    "Writes an end of line, as for TERPRI. Returns NIL. The default
 391   method does (STREAM-WRITE-CHAR stream #\NEWLINE)."))
 392
 393 (defmethod stream-terpri ((stream fundamental-character-output-stream))
 394   (stream-write-char stream #\Newline))
 395
 396 (defgeneric stream-fresh-line (stream)
 397   #+sb-doc
 398   (:documentation
 399    "Outputs a new line to the Stream if it is not positioned at the
 400   begining of a line. Returns T if it output a new line, nil
 401   otherwise. Used by FRESH-LINE. The default method uses
 402   STREAM-START-LINE-P and STREAM-TERPRI."))
 403
 404 (defmethod stream-fresh-line ((stream fundamental-character-output-stream))
 405   (unless (stream-start-line-p stream)
 406     (stream-terpri stream)
 407     t))
 408
 409 (defgeneric stream-finish-output (stream)
 410   #+sb-doc
 411   (:documentation
 412    "Attempts to ensure that all output sent to the Stream has reached
 413   its destination, and only then returns false. Implements
 414   FINISH-OUTPUT. The default method does nothing."))
 415
 416 (defmethod stream-finish-output ((stream fundamental-output-stream))
 417   nil)
 418 (defmethod stream-finish-output ((stream stream))
 419   (bug-or-error stream 'stream-finish-output))
 420 (defmethod stream-finish-output ((non-stream t))
 421   (error 'type-error :datum non-stream :expected-type 'stream))
 422
 423 (defgeneric stream-force-output (stream)
 424   #+sb-doc
 425   (:documentation
 426    "Attempts to force any buffered output to be sent. Implements
 427   FORCE-OUTPUT. The default method does nothing."))
 428
 429 (defmethod stream-force-output ((stream fundamental-output-stream))
 430   nil)
 431 (defmethod stream-force-output ((stream stream))
 432   (bug-or-error stream 'stream-force-output))
 433 (defmethod stream-force-output ((non-stream t))
 434   (error 'type-error :datum non-stream :expected-type 'stream))
 435
 436 (defgeneric stream-clear-output (stream)
 437   #+sb-doc
 438   (:documentation
 439    "This is like CL:CLEAR-OUTPUT, but for Gray streams: clear the given
 440   output STREAM. The default method does nothing."))
 441
 442 (defmethod stream-clear-output ((stream fundamental-output-stream))
 443   nil)
 444 (defmethod stream-clear-output ((stream stream))
 445   (bug-or-error stream 'stream-clear-output))
 446 (defmethod stream-clear-output ((non-stream t))
 447   (error 'type-error :datum non-stream :expected-type 'stream))
 448
 449 (defgeneric stream-advance-to-column (stream column)
 450   #+sb-doc
 451   (:documentation
 452    "Write enough blank space so that the next character will be
 453   written at the specified column. Returns true if the operation is
 454   successful, or NIL if it is not supported for this stream. This is
 455   intended for use by by PPRINT and FORMAT ~T. The default method uses
 456   STREAM-LINE-COLUMN and repeated calls to STREAM-WRITE-CHAR with a
 457   #\SPACE character; it returns NIL if STREAM-LINE-COLUMN returns NIL."))
 458
 459 (defmethod stream-advance-to-column ((stream fundamental-character-output-stream)
 460                                      column)
 461   (let ((current-column (stream-line-column stream)))
 462     (when current-column
 463       (let ((fill (- column current-column)))
 464         (dotimes (i fill)
 465           (stream-write-char stream #\Space)))
 466       T)))
 467
 468 (defgeneric stream-write-sequence (stream seq &optional start end)
 469   #+sb-doc
 470   (:documentation
 471    "This is like CL:WRITE-SEQUENCE, but for Gray streams."))
 472
 473 ;;; Write the elements of SEQ bounded by START and END to STREAM.
 474 (defun basic-io-type-stream-write-sequence (stream seq start end write-fun)
 475   (declare (type sequence seq)
 476            (type stream stream)
 477            (type index start)
 478            (type sequence-end end)
 479            (type function write-fun)
 480            (values sequence))
 481   (let ((end (or end (length seq))))
 482     (declare (type index start end))
 483     (etypecase seq
 484       (list
 485         (do ((rem (nthcdr start seq) (rest rem))
 486              (i start (1+ i)))
 487             ((or (endp rem) (>= i end)) seq)
 488           (declare (type list rem)
 489                    (type index i))
 490           (funcall write-fun stream (first rem))))
 491       (vector
 492         (do ((i start (1+ i)))
 493             ((>= i end) seq)
 494           (declare (type index i))
 495           (funcall write-fun stream (aref seq i)))))))
 496
 497 (defmethod stream-write-sequence ((stream fundamental-character-output-stream)
 498                                   (seq sequence)
 499                                   &optional (start 0) (end nil))
 500   (typecase seq
 501     (string
 502       (stream-write-string stream seq start end))
 503     (t
 504       (basic-io-type-stream-write-sequence stream seq start end
 505                                            #'stream-write-char))))
 506
 507 \f
 508 ;;; binary streams
 509 ;;;
 510 ;;; Binary streams can be created by defining a class that includes
 511 ;;; either FUNDAMENTAL-BINARY-INPUT-STREAM or
 512 ;;; FUNDAMENTAL-BINARY-OUTPUT-STREAM (or both) and defining a method
 513 ;;; for STREAM-ELEMENT-TYPE and for one or both of the following
 514 ;;; generic functions.
 515
 516 (defgeneric stream-read-byte (stream)
 517   #+sb-doc
 518   (:documentation
 519    "Used by READ-BYTE; returns either an integer, or the symbol :EOF
 520   if the stream is at end-of-file."))
 521
 522 (defmethod stream-read-byte ((stream stream))
 523   (bug-or-error stream 'stream-read-byte))
 524 (defmethod stream-read-byte ((non-stream t))
 525   (error 'type-error :datum non-stream :expected-type 'stream))
 526
 527 (defgeneric stream-write-byte (stream integer)
 528   #+sb-doc
 529   (:documentation
 530    "Implements WRITE-BYTE; writes the integer to the stream and
 531   returns the integer as the result."))
 532
 533 (defmethod stream-write-byte ((stream stream) integer)
 534   (bug-or-error stream 'stream-write-byte))
 535 (defmethod stream-write-byte ((non-stream t) integer)
 536   (error 'type-error :datum non-stream :expected-type 'stream))
 537
 538 ;; Provide a reasonable default for binary Gray streams.  We might be
 539 ;; able to do better by specializing on the sequence type, but at
 540 ;; least the behaviour is reasonable. --tony 2003/05/08.
 541 (defmethod stream-write-sequence ((stream fundamental-binary-output-stream)
 542                                   (seq sequence)
 543                                   &optional (start 0) (end nil))
 544   (basic-io-type-stream-write-sequence stream seq start end
 545                                        #'stream-write-byte))
 546
 547 (defgeneric stream-file-position (stream &optional position-spec)
 548   #+sb-doc
 549   (:documentation
 550    "Used by FILE-POSITION. Returns or changes the current position within STREAM."))
 551
 552 (defmethod stream-file-position ((stream ansi-stream) &optional position-spec)
 553   (ansi-stream-file-position stream position-spec))
 554
 555 (defmethod stream-file-position ((stream t) &optional position-spec)
 556   (declare (ignore stream position-spec))
 557   nil)
 558
 559 \f
 560 ;;; This is not in the Gray stream proposal, so it is left here
 561 ;;; as example code.
 562 #|
 563 ;;; example character output stream encapsulating a lisp-stream
 564 (defun make-character-output-stream (lisp-stream)
 565   (declare (type lisp-stream lisp-stream))
 566   (make-instance 'character-output-stream :lisp-stream lisp-stream))
 567
 568 (defmethod open-stream-p ((stream character-output-stream))
 569   (open-stream-p (character-output-stream-lisp-stream stream)))
 570
 571 (defmethod close ((stream character-output-stream) &key abort)
 572   (close (character-output-stream-lisp-stream stream) :abort abort))
 573
 574 (defmethod input-stream-p ((stream character-output-stream))
 575   (input-stream-p (character-output-stream-lisp-stream stream)))
 576
 577 (defmethod output-stream-p ((stream character-output-stream))
 578   (output-stream-p (character-output-stream-lisp-stream stream)))
 579
 580 (defmethod stream-write-char ((stream character-output-stream) character)
 581   (write-char character (character-output-stream-lisp-stream stream)))
 582
 583 (defmethod stream-line-column ((stream character-output-stream))
 584   (charpos (character-output-stream-lisp-stream stream)))
 585
 586 (defmethod stream-line-length ((stream character-output-stream))
 587   (line-length (character-output-stream-lisp-stream stream)))
 588
 589 (defmethod stream-finish-output ((stream character-output-stream))
 590   (finish-output (character-output-stream-lisp-stream stream)))
 591
 592 (defmethod stream-force-output ((stream character-output-stream))
 593   (force-output (character-output-stream-lisp-stream stream)))
 594
 595 (defmethod stream-clear-output ((stream character-output-stream))
 596   (clear-output (character-output-stream-lisp-stream stream)))
 597 \f
 598 ;;; example character input stream encapsulating a lisp-stream
 599
 600 (defun make-character-input-stream (lisp-stream)
 601   (declare (type lisp-stream lisp-stream))
 602   (make-instance 'character-input-stream :lisp-stream lisp-stream))
 603
 604 (defmethod open-stream-p ((stream character-input-stream))
 605   (open-stream-p (character-input-stream-lisp-stream stream)))
 606
 607 (defmethod close ((stream character-input-stream) &key abort)
 608   (close (character-input-stream-lisp-stream stream) :abort abort))
 609
 610 (defmethod input-stream-p ((stream character-input-stream))
 611   (input-stream-p (character-input-stream-lisp-stream stream)))
 612
 613 (defmethod output-stream-p ((stream character-input-stream))
 614   (output-stream-p (character-input-stream-lisp-stream stream)))
 615
 616 (defmethod stream-read-char ((stream character-input-stream))
 617   (read-char (character-input-stream-lisp-stream stream) nil :eof))
 618
 619 (defmethod stream-unread-char ((stream character-input-stream) character)
 620   (unread-char character (character-input-stream-lisp-stream stream)))
 621
 622 (defmethod stream-read-char-no-hang ((stream character-input-stream))
 623   (read-char-no-hang (character-input-stream-lisp-stream stream) nil :eof))
 624
 625 #+nil
 626 (defmethod stream-peek-char ((stream character-input-stream))
 627   (peek-char nil (character-input-stream-lisp-stream stream) nil :eof))
 628
 629 #+nil
 630 (defmethod stream-listen ((stream character-input-stream))
 631   (listen (character-input-stream-lisp-stream stream)))
 632
 633 (defmethod stream-clear-input ((stream character-input-stream))
 634   (clear-input (character-input-stream-lisp-stream stream)))
 635 |#