src/code/reader.lisp

   1 ;;;; READ and friends
   2
   3 ;;;; This software is part of the SBCL system. See the README file for
   4 ;;;; more information.
   5 ;;;;
   6 ;;;; This software is derived from the CMU CL system, which was
   7 ;;;; written at Carnegie Mellon University and released into the
   8 ;;;; public domain. The software is in the public domain and is
   9 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
  10 ;;;; files for more information.
  11
  12 (in-package "SB!IMPL")
  13 \f
  14 ;;;; miscellaneous global variables
  15
  16 ;;; ANSI: "the floating-point format that is to be used when reading a
  17 ;;; floating-point number that has no exponent marker or that has e or
  18 ;;; E for an exponent marker"
  19 (defvar *read-default-float-format* 'single-float)
  20 (declaim (type (member short-float single-float double-float long-float)
  21                *read-default-float-format*))
  22
  23 (defvar *readtable*)
  24 (declaim (type readtable *readtable*))
  25 #!+sb-doc
  26 (setf (fdocumentation '*readtable* 'variable)
  27        "Variable bound to current readtable.")
  28
  29 ;;; a standard Lisp readtable. This is for recovery from broken
  30 ;;; read-tables (and for WITH-STANDARD-IO-SYNTAX), and should not
  31 ;;; normally be user-visible.
  32 (defvar *standard-readtable*)
  33
  34 (defvar *old-package* nil
  35   #!+sb-doc
  36   "the value of *PACKAGE* at the start of the last read, or NIL")
  37
  38 ;;; In case we get an error trying to parse a symbol, we want to rebind the
  39 ;;; above stuff so it's cool.
  40
  41 ;;; FIXME: These forward declarations should be moved somewhere earlier,
  42 ;;; or discarded.
  43 (declaim (special *package* *keyword-package* *read-base*))
  44 \f
  45 ;;;; reader errors
  46
  47 (defun reader-eof-error (stream context)
  48   (error 'reader-eof-error
  49          :stream stream
  50          :context context))
  51
  52 (defun %reader-error (stream control &rest args)
  53   (error 'reader-error
  54          :stream stream
  55          :format-control control
  56          :format-arguments args))
  57 \f
  58 ;;;; macros and functions for character tables
  59
  60 ;;; FIXME: could be SB!XC:DEFMACRO inside EVAL-WHEN (COMPILE EVAL)
  61 (defmacro get-cat-entry (char rt)
  62   ;; KLUDGE: Only give this side-effect-free args.
  63   ;; FIXME: should probably become inline function
  64   `(if (typep ,char 'base-char)
  65        (elt (character-attribute-array ,rt) (char-code ,char))
  66        (gethash ,char (character-attribute-hash-table ,rt)
  67         +char-attr-constituent+)))
  68
  69 (defun set-cat-entry (char newvalue &optional (rt *readtable*))
  70   (if (typep char 'base-char)
  71       (setf (elt (character-attribute-array rt) (char-code char)) newvalue)
  72       ;; FIXME: could REMHASH if we're setting to
  73       ;; +CHAR-ATTR-CONSTITUENT+
  74       (setf (gethash char (character-attribute-hash-table rt)) newvalue)))
  75
  76 ;;; the value actually stored in the character macro table. As per
  77 ;;; ANSI #'GET-MACRO-CHARACTER and #'SET-MACRO-CHARACTER, this can
  78 ;;; be either a function or NIL.
  79 (eval-when (:compile-toplevel :execute)
  80   (sb!xc:defmacro get-raw-cmt-entry (char readtable)
  81     `(if (typep ,char 'base-char)
  82          (svref (character-macro-array ,readtable) (char-code ,char))
  83          ;; Note: DEFAULT here is NIL, not #'UNDEFINED-MACRO-CHAR, so
  84          ;; that everything above the base-char range is a non-macro
  85          ;; constituent by default.
  86          (gethash ,char (character-macro-hash-table ,readtable) nil))))
  87
  88 ;;; the value represented by whatever is stored in the character macro
  89 ;;; table. As per ANSI #'GET-MACRO-CHARACTER and #'SET-MACRO-CHARACTER,
  90 ;;; a function value represents itself, and a NIL value represents the
  91 ;;; default behavior.
  92 (defun get-coerced-cmt-entry (char readtable)
  93   (the function
  94     (or (get-raw-cmt-entry char readtable)
  95         #'read-token)))
  96
  97 (defun set-cmt-entry (char new-value-designator &optional (rt *readtable*))
  98   (if (typep char 'base-char)
  99       (setf (svref (character-macro-array rt) (char-code char))
 100             (and new-value-designator
 101                  (%coerce-callable-to-fun new-value-designator)))
 102       (setf (gethash char (character-macro-hash-table rt))
 103         (and new-value-designator
 104                  (%coerce-callable-to-fun new-value-designator)))))
 105
 106 (defun undefined-macro-char (stream char)
 107   (unless *read-suppress*
 108     (%reader-error stream "undefined read-macro character ~S" char)))
 109
 110 ;;; The character attribute table is a CHAR-CODE-LIMIT vector of integers.
 111
 112 (defmacro test-attribute (char whichclass rt)
 113   `(= (the fixnum (get-cat-entry ,char ,rt)) ,whichclass))
 114
 115 ;;; predicates for testing character attributes
 116
 117 ;;; the [1] and [2] here refer to ANSI glossary entries for
 118 ;;; "whitespace".
 119 #!-sb-fluid (declaim (inline whitespace[1]p whitespace[2]p))
 120 (defun whitespace[1]p (char)
 121   (test-attribute char +char-attr-whitespace+ *standard-readtable*))
 122 (defun whitespace[2]p (char &optional (rt *readtable*))
 123   (test-attribute char +char-attr-whitespace+ rt))
 124
 125 (defmacro constituentp (char &optional (rt '*readtable*))
 126   `(test-attribute ,char +char-attr-constituent+ ,rt))
 127
 128 (defmacro terminating-macrop (char &optional (rt '*readtable*))
 129   `(test-attribute ,char +char-attr-terminating-macro+ ,rt))
 130
 131 (defmacro single-escape-p (char &optional (rt '*readtable*))
 132   `(test-attribute ,char +char-attr-single-escape+ ,rt))
 133
 134 (defmacro multiple-escape-p (char &optional (rt '*readtable*))
 135   `(test-attribute ,char +char-attr-multiple-escape+ ,rt))
 136
 137 (defmacro token-delimiterp (char &optional (rt '*readtable*))
 138   ;; depends on actual attribute numbering above.
 139   `(<= (get-cat-entry ,char ,rt) +char-attr-terminating-macro+))
 140 \f
 141 ;;;; constituent traits (see ANSI 2.1.4.2)
 142
 143 ;;; There are a number of "secondary" attributes which are constant
 144 ;;; properties of characters (as long as they are constituents).
 145
 146 (defvar *constituent-trait-table*)
 147 (declaim (type attribute-table *constituent-trait-table*))
 148
 149 (defun !set-constituent-trait (char trait)
 150   (aver (typep char 'base-char))
 151   (setf (elt *constituent-trait-table* (char-code char))
 152         trait))
 153
 154 (defun !cold-init-constituent-trait-table ()
 155   (setq *constituent-trait-table*
 156         (make-array base-char-code-limit :element-type '(unsigned-byte 8)
 157                     :initial-element +char-attr-constituent+))
 158   (!set-constituent-trait #\: +char-attr-package-delimiter+)
 159   (!set-constituent-trait #\. +char-attr-constituent-dot+)
 160   (!set-constituent-trait #\+ +char-attr-constituent-sign+)
 161   (!set-constituent-trait #\- +char-attr-constituent-sign+)
 162   (!set-constituent-trait #\/ +char-attr-constituent-slash+)
 163   (do ((i (char-code #\0) (1+ i)))
 164       ((> i (char-code #\9)))
 165     (!set-constituent-trait (code-char i) +char-attr-constituent-digit+))
 166   (!set-constituent-trait #\E +char-attr-constituent-expt+)
 167   (!set-constituent-trait #\F +char-attr-constituent-expt+)
 168   (!set-constituent-trait #\D +char-attr-constituent-expt+)
 169   (!set-constituent-trait #\S +char-attr-constituent-expt+)
 170   (!set-constituent-trait #\L +char-attr-constituent-expt+)
 171   (!set-constituent-trait #\e +char-attr-constituent-expt+)
 172   (!set-constituent-trait #\f +char-attr-constituent-expt+)
 173   (!set-constituent-trait #\d +char-attr-constituent-expt+)
 174   (!set-constituent-trait #\s +char-attr-constituent-expt+)
 175   (!set-constituent-trait #\l +char-attr-constituent-expt+)
 176   (!set-constituent-trait #\Space +char-attr-invalid+)
 177   (!set-constituent-trait #\Newline +char-attr-invalid+)
 178   (dolist (c (list backspace-char-code tab-char-code form-feed-char-code
 179                    return-char-code rubout-char-code))
 180     (!set-constituent-trait (code-char c) +char-attr-invalid+)))
 181
 182 (defmacro get-constituent-trait (char)
 183   `(if (typep ,char 'base-char)
 184        (elt *constituent-trait-table* (char-code ,char))
 185        +char-attr-constituent+))
 186 \f
 187 ;;;; readtable operations
 188
 189 (defun shallow-replace/eql-hash-table (to from)
 190   (maphash (lambda (k v) (setf (gethash k to) v)) from))
 191
 192 (defun copy-readtable (&optional (from-readtable *readtable*)
 193                                  to-readtable)
 194   (let ((really-from-readtable (or from-readtable *standard-readtable*))
 195         (really-to-readtable (or to-readtable (make-readtable))))
 196     (replace (character-attribute-array really-to-readtable)
 197              (character-attribute-array really-from-readtable))
 198     (shallow-replace/eql-hash-table
 199      (character-attribute-hash-table really-to-readtable)
 200      (character-attribute-hash-table really-from-readtable))
 201     (replace (character-macro-array really-to-readtable)
 202              (character-macro-array really-from-readtable))
 203     (shallow-replace/eql-hash-table
 204      (character-macro-hash-table really-to-readtable)
 205      (character-macro-hash-table really-from-readtable))
 206     (setf (dispatch-tables really-to-readtable)
 207           (mapcar (lambda (pair)
 208                     (cons (car pair)
 209                           (let ((table (make-hash-table)))
 210                             (shallow-replace/eql-hash-table table (cdr pair))
 211                             table)))
 212                   (dispatch-tables really-from-readtable)))
 213     (setf (readtable-case really-to-readtable)
 214           (readtable-case really-from-readtable))
 215     really-to-readtable))
 216
 217 (defun set-syntax-from-char (to-char from-char &optional
 218                              (to-readtable *readtable*) (from-readtable ()))
 219   #!+sb-doc
 220   "Causes the syntax of TO-CHAR to be the same as FROM-CHAR in the optional
 221 readtable (defaults to the current readtable). The FROM-TABLE defaults to the
 222 standard Lisp readtable when NIL."
 223   (let ((really-from-readtable (or from-readtable *standard-readtable*)))
 224     (let ((att (get-cat-entry from-char really-from-readtable))
 225           (mac (get-raw-cmt-entry from-char really-from-readtable))
 226           (from-dpair (find from-char (dispatch-tables really-from-readtable)
 227                             :test #'char= :key #'car))
 228           (to-dpair (find to-char (dispatch-tables to-readtable)
 229                           :test #'char= :key #'car)))
 230       (set-cat-entry to-char att to-readtable)
 231       (set-cmt-entry to-char mac to-readtable)
 232       (when from-dpair
 233         (cond
 234           (to-dpair
 235            (let ((table (cdr to-dpair)))
 236              (clrhash table)
 237              (shallow-replace/eql-hash-table table (cdr from-dpair))))
 238           (t
 239            (let ((pair (cons to-char (make-hash-table))))
 240              (shallow-replace/eql-hash-table (cdr pair) (cdr from-dpair))
 241              (setf (dispatch-tables to-readtable)
 242                    (push pair (dispatch-tables to-readtable)))))))))
 243   t)
 244
 245 (defun set-macro-character (char function &optional
 246                                  (non-terminatingp nil)
 247                                  (readtable *readtable*))
 248   #!+sb-doc
 249   "Causes CHAR to be a macro character which invokes FUNCTION when seen
 250    by the reader. The NON-TERMINATINGP flag can be used to make the macro
 251    character non-terminating, i.e. embeddable in a symbol name."
 252   (let ((designated-readtable (or readtable *standard-readtable*)))
 253     (set-cat-entry char (if non-terminatingp
 254                             +char-attr-constituent+
 255                             +char-attr-terminating-macro+)
 256                    designated-readtable)
 257     (set-cmt-entry char function designated-readtable)
 258     t)) ; (ANSI-specified return value)
 259
 260 (defun get-macro-character (char &optional (readtable *readtable*))
 261   #!+sb-doc
 262   "Return the function associated with the specified CHAR which is a macro
 263   character, or NIL if there is no such function. As a second value, return
 264   T if CHAR is a macro character which is non-terminating, i.e. which can
 265   be embedded in a symbol name."
 266   (let* ((designated-readtable (or readtable *standard-readtable*))
 267          ;; the first return value: a FUNCTION if CHAR is a macro
 268          ;; character, or NIL otherwise
 269          (fun-value (get-raw-cmt-entry char designated-readtable)))
 270     (values fun-value
 271             ;; NON-TERMINATING-P return value:
 272             (if fun-value
 273                 (or (constituentp char)
 274                     (not (terminating-macrop char)))
 275                 ;; ANSI's definition of GET-MACRO-CHARACTER says this
 276                 ;; value is NIL when CHAR is not a macro character.
 277                 ;; I.e. this value means not just "non-terminating
 278                 ;; character?" but "non-terminating macro character?".
 279                 nil))))
 280 \f
 281 ;;;; definitions to support internal programming conventions
 282
 283 (defmacro eofp (char)
 284   `(eq ,char *eof-object*))
 285
 286 (defun flush-whitespace (stream)
 287   ;; This flushes whitespace chars, returning the last char it read (a
 288   ;; non-white one). It always gets an error on end-of-file.
 289   (let ((stream (in-synonym-of stream)))
 290     (if (ansi-stream-p stream)
 291         (prepare-for-fast-read-char stream
 292           (do ((attribute-array (character-attribute-array *readtable*))
 293                (attribute-hash-table
 294                 (character-attribute-hash-table *readtable*))
 295                (char (fast-read-char t) (fast-read-char t)))
 296               ((/= (the fixnum
 297                      (if (typep char 'base-char)
 298                          (aref attribute-array (char-code char))
 299                          (gethash char attribute-hash-table
 300                                   +char-attr-constituent+)))
 301                    +char-attr-whitespace+)
 302                (done-with-fast-read-char)
 303                char)))
 304         ;; CLOS stream
 305         (do ((attribute-array (character-attribute-array *readtable*))
 306              (attribute-hash-table
 307               (character-attribute-hash-table *readtable*))
 308              (char (read-char stream nil :eof) (read-char stream nil :eof)))
 309             ((or (eq char :eof)
 310                  (/= (the fixnum
 311                        (if (typep char 'base-char)
 312                            (aref attribute-array (char-code char))
 313                            (gethash char attribute-hash-table
 314                                     +char-attr-constituent+)))
 315                      +char-attr-whitespace+))
 316              (if (eq char :eof)
 317                  (error 'end-of-file :stream stream)
 318                  char))))))
 319 \f
 320 ;;;; temporary initialization hack
 321
 322 (defun !cold-init-standard-readtable ()
 323   (setq *standard-readtable* (make-readtable))
 324   ;; All characters get boring defaults in MAKE-READTABLE. Now we
 325   ;; override the boring defaults on characters which need more
 326   ;; interesting behavior.
 327   (let ((*readtable* *standard-readtable*))
 328
 329     (flet ((whitespaceify (char)
 330              (set-cmt-entry char nil)
 331              (set-cat-entry char +char-attr-whitespace+)))
 332       (whitespaceify (code-char tab-char-code))
 333       (whitespaceify #\Newline)
 334       (whitespaceify #\Space)
 335       (whitespaceify (code-char form-feed-char-code))
 336       (whitespaceify (code-char return-char-code)))
 337
 338     (set-cat-entry #\\ +char-attr-single-escape+)
 339     (set-cmt-entry #\\ nil)
 340
 341     (set-cat-entry #\| +char-attr-multiple-escape+)
 342     (set-cmt-entry #\| nil)
 343
 344     ;; Easy macro-character definitions are in this source file.
 345     (set-macro-character #\" #'read-string)
 346     (set-macro-character #\' #'read-quote)
 347     (set-macro-character #\( #'read-list)
 348     (set-macro-character #\) #'read-right-paren)
 349     (set-macro-character #\; #'read-comment)
 350     ;; (The hairier macro-character definitions, for #\# and #\`, are
 351     ;; defined elsewhere, in their own source files.)
 352
 353     ;; all constituents
 354     (do ((ichar 0 (1+ ichar))
 355          (char))
 356         ((= ichar base-char-code-limit))
 357       (setq char (code-char ichar))
 358       (when (constituentp char *standard-readtable*)
 359         (set-cmt-entry char nil)))))
 360 \f
 361 ;;;; implementation of the read buffer
 362
 363 (defvar *read-buffer*)
 364 (defvar *read-buffer-length*)
 365 ;;; FIXME: Is it really helpful to have *READ-BUFFER-LENGTH* be a
 366 ;;; separate variable instead of just calculating it on the fly as
 367 ;;; (LENGTH *READ-BUFFER*)?
 368
 369 (defvar *inch-ptr*)
 370 (defvar *ouch-ptr*)
 371
 372 (declaim (type index *read-buffer-length* *inch-ptr* *ouch-ptr*))
 373 (declaim (type (simple-array character (*)) *read-buffer*))
 374
 375 (defmacro reset-read-buffer ()
 376   ;; Turn *READ-BUFFER* into an empty read buffer.
 377   `(progn
 378      ;; *OUCH-PTR* always points to next char to write.
 379      (setq *ouch-ptr* 0)
 380      ;; *INCH-PTR* always points to next char to read.
 381      (setq *inch-ptr* 0)))
 382
 383 ;;; FIXME I removed "THE FIXNUM"'s from OUCH-READ-BUFFER and
 384 ;;; OUCH-UNREAD-BUFFER, check to make sure that Python really is smart
 385 ;;; enough to make good code without them. And while I'm at it,
 386 ;;; converting them from macros to inline functions might be good,
 387 ;;; too.
 388
 389 (defmacro ouch-read-buffer (char)
 390   `(progn
 391      ;; When buffer overflow
 392      (when (>= *ouch-ptr* *read-buffer-length*)
 393        ;; Size should be doubled.
 394        (grow-read-buffer))
 395      (setf (elt (the simple-string *read-buffer*) *ouch-ptr*) ,char)
 396      (setq *ouch-ptr* (1+ *ouch-ptr*))))
 397
 398 ;;; macro to move *ouch-ptr* back one.
 399 (defmacro ouch-unread-buffer ()
 400   '(when (> *ouch-ptr* *inch-ptr*)
 401      (setq *ouch-ptr* (1- (the fixnum *ouch-ptr*)))))
 402
 403 (defun grow-read-buffer ()
 404   (let* ((rbl (length *read-buffer*))
 405          (new-length (* 2 rbl))
 406          (new-buffer (make-string new-length)))
 407     (setq *read-buffer* (replace new-buffer *read-buffer*))
 408     (setq *read-buffer-length* new-length)))
 409
 410 (defun inchpeek-read-buffer ()
 411   (if (>= (the fixnum *inch-ptr*) (the fixnum *ouch-ptr*))
 412       *eof-object*
 413       (elt *read-buffer* *inch-ptr*)))
 414
 415 (defun inch-read-buffer ()
 416   (if (>= *inch-ptr* *ouch-ptr*)
 417       *eof-object*
 418       (prog1
 419           (elt *read-buffer* *inch-ptr*)
 420         (incf *inch-ptr*))))
 421
 422 (defmacro unread-buffer ()
 423   `(decf *inch-ptr*))
 424
 425 (defun read-unwind-read-buffer ()
 426   ;; Keep contents, but make next (INCH..) return first character.
 427   (setq *inch-ptr* 0))
 428
 429 (defun read-buffer-to-string ()
 430   (subseq *read-buffer* 0 *ouch-ptr*))
 431
 432 (defmacro with-reader ((&optional recursive-p) &body body)
 433   #!+sb-doc
 434   "If RECURSIVE-P is NIL, bind *READER-BUFFER* and its subservient
 435 variables to allow for nested and thread safe reading."
 436   `(if ,recursive-p
 437        (progn ,@body)
 438        (let* ((*read-buffer* (make-string 128))
 439               (*read-buffer-length* 128)
 440               (*ouch-ptr* 0)
 441               (*inch-ptr* 0))
 442          ,@body)))
 443 \f
 444 ;;;; READ-PRESERVING-WHITESPACE, READ-DELIMITED-LIST, and READ
 445
 446 ;;; an alist for #=, used to keep track of objects with labels assigned that
 447 ;;; have been completely read. Each entry is (integer-tag gensym-tag value).
 448 ;;;
 449 ;;; KLUDGE: Should this really be an alist? It seems as though users
 450 ;;; could reasonably expect N log N performance for large datasets.
 451 ;;; On the other hand, it's probably very very seldom a problem in practice.
 452 ;;; On the third hand, it might be just as easy to use a hash table
 453 ;;; as an alist, so maybe we should. -- WHN 19991202
 454 (defvar *sharp-equal-alist* ())
 455
 456 (declaim (special *standard-input*))
 457
 458 ;;; READ-PRESERVING-WHITESPACE behaves just like READ, only it makes
 459 ;;; sure to leave terminating whitespace in the stream. (This is a
 460 ;;; COMMON-LISP exported symbol.)
 461 (defun read-preserving-whitespace (&optional (stream *standard-input*)
 462                                              (eof-error-p t)
 463                                              (eof-value nil)
 464                                              (recursivep nil))
 465   #!+sb-doc
 466   "Read from STREAM and return the value read, preserving any whitespace
 467    that followed the object."
 468   (if recursivep
 469       ;; a loop for repeating when a macro returns nothing
 470       (loop
 471        (let ((char (read-char stream eof-error-p *eof-object*)))
 472          (cond ((eofp char) (return eof-value))
 473                ((whitespace[2]p char))
 474                (t
 475                 (let* ((macrofun (get-coerced-cmt-entry char *readtable*))
 476                        (result (multiple-value-list
 477                                 (funcall macrofun stream char))))
 478                   ;; Repeat if macro returned nothing.
 479                   (when result
 480                     (return (unless *read-suppress* (car result)))))))))
 481       (with-reader ()
 482         (let ((*sharp-equal-alist* nil))
 483           (read-preserving-whitespace stream eof-error-p eof-value t)))))
 484
 485 ;;; Return NIL or a list with one thing, depending.
 486 ;;;
 487 ;;; for functions that want comments to return so that they can look
 488 ;;; past them. We assume CHAR is not whitespace.
 489 (defun read-maybe-nothing (stream char)
 490   (let ((retval (multiple-value-list
 491                  (funcall (get-coerced-cmt-entry char *readtable*)
 492                           stream
 493                           char))))
 494     (if retval (rplacd retval nil))))
 495
 496 (defun read (&optional (stream *standard-input*)
 497                        (eof-error-p t)
 498                        (eof-value ())
 499                        (recursivep ()))
 500   #!+sb-doc
 501   "Read the next Lisp value from STREAM, and return it."
 502   (let ((result (read-preserving-whitespace stream
 503                                             eof-error-p
 504                                             eof-value
 505                                             recursivep)))
 506     ;; This function generally discards trailing whitespace. If you
 507     ;; don't want to discard trailing whitespace, call
 508     ;; CL:READ-PRESERVING-WHITESPACE instead.
 509     (unless (or (eql result eof-value) recursivep)
 510       (let ((next-char (read-char stream nil nil)))
 511         (unless (or (null next-char)
 512                     (whitespace[2]p next-char))
 513           (unread-char next-char stream))))
 514     result))
 515
 516 ;;; (This is a COMMON-LISP exported symbol.)
 517 (defun read-delimited-list (endchar &optional
 518                                     (input-stream *standard-input*)
 519                                     recursive-p)
 520   #!+sb-doc
 521   "Read Lisp values from INPUT-STREAM until the next character after a
 522    value's representation is ENDCHAR, and return the objects as a list."
 523   (with-reader (recursive-p)
 524     (do ((char (flush-whitespace input-stream)
 525                (flush-whitespace input-stream))
 526          (retlist ()))
 527         ((char= char endchar) (unless *read-suppress* (nreverse retlist)))
 528       (setq retlist (nconc (read-maybe-nothing input-stream char) retlist)))))
 529 \f
 530 ;;;; basic readmacro definitions
 531 ;;;;
 532 ;;;; Some large, hairy subsets of readmacro definitions (backquotes
 533 ;;;; and sharp macros) are not here, but in their own source files.
 534
 535 (defun read-quote (stream ignore)
 536   (declare (ignore ignore))
 537   (list 'quote (read stream t nil t)))
 538
 539 (defun read-comment (stream ignore)
 540   (declare (ignore ignore))
 541   (handler-bind
 542       ((character-decoding-error
 543         #'(lambda (decoding-error)
 544             (declare (ignorable decoding-error))
 545             (style-warn "Character decoding error in a ;-comment at position ~A reading source file ~A, resyncing." (file-position stream) stream)
 546             (invoke-restart 'attempt-resync))))
 547     (let ((stream (in-synonym-of stream)))
 548       (if (ansi-stream-p stream)
 549           (prepare-for-fast-read-char stream
 550            (do ((char (fast-read-char nil nil)
 551                       (fast-read-char nil nil)))
 552                ((or (not char) (char= char #\newline))
 553                 (done-with-fast-read-char))))
 554           ;; CLOS stream
 555           (do ((char (read-char stream nil :eof) (read-char stream nil :eof)))
 556               ((or (eq char :eof) (char= char #\newline)))))))
 557   ;; Don't return anything.
 558   (values))
 559
 560 (defun read-list (stream ignore)
 561   (declare (ignore ignore))
 562   (let* ((thelist (list nil))
 563          (listtail thelist))
 564     (do ((firstchar (flush-whitespace stream) (flush-whitespace stream)))
 565         ((char= firstchar #\) ) (cdr thelist))
 566       (when (char= firstchar #\.)
 567             (let ((nextchar (read-char stream t)))
 568               (cond ((token-delimiterp nextchar)
 569                      (cond ((eq listtail thelist)
 570                             (unless *read-suppress*
 571                               (%reader-error
 572                                stream
 573                                "Nothing appears before . in list.")))
 574                            ((whitespace[2]p nextchar)
 575                             (setq nextchar (flush-whitespace stream))))
 576                      (rplacd listtail
 577                              ;; Return list containing last thing.
 578                              (car (read-after-dot stream nextchar)))
 579                      (return (cdr thelist)))
 580                     ;; Put back NEXTCHAR so that we can read it normally.
 581                     (t (unread-char nextchar stream)))))
 582       ;; Next thing is not an isolated dot.
 583       (let ((listobj (read-maybe-nothing stream firstchar)))
 584         ;; allows the possibility that a comment was read
 585         (when listobj
 586               (rplacd listtail listobj)
 587               (setq listtail listobj))))))
 588
 589 (defun read-after-dot (stream firstchar)
 590   ;; FIRSTCHAR is non-whitespace!
 591   (let ((lastobj ()))
 592     (do ((char firstchar (flush-whitespace stream)))
 593         ((char= char #\) )
 594          (if *read-suppress*
 595              (return-from read-after-dot nil)
 596              (%reader-error stream "Nothing appears after . in list.")))
 597       ;; See whether there's something there.
 598       (setq lastobj (read-maybe-nothing stream char))
 599       (when lastobj (return t)))
 600     ;; At least one thing appears after the dot.
 601     ;; Check for more than one thing following dot.
 602     (do ((lastchar (flush-whitespace stream)
 603                    (flush-whitespace stream)))
 604         ((char= lastchar #\) ) lastobj) ;success!
 605       ;; Try reading virtual whitespace.
 606       (if (and (read-maybe-nothing stream lastchar)
 607                (not *read-suppress*))
 608           (%reader-error stream "More than one object follows . in list.")))))
 609
 610 (defun read-string (stream closech)
 611   ;; This accumulates chars until it sees same char that invoked it.
 612   ;; For a very long string, this could end up bloating the read buffer.
 613   (reset-read-buffer)
 614   (let ((stream (in-synonym-of stream)))
 615     (if (ansi-stream-p stream)
 616         (prepare-for-fast-read-char stream
 617           (do ((char (fast-read-char t) (fast-read-char t)))
 618               ((char= char closech)
 619                (done-with-fast-read-char))
 620             (if (single-escape-p char) (setq char (fast-read-char t)))
 621             (ouch-read-buffer char)))
 622         ;; CLOS stream
 623         (do ((char (read-char stream nil :eof) (read-char stream nil :eof)))
 624             ((or (eq char :eof) (char= char closech))
 625              (if (eq char :eof)
 626                  (error 'end-of-file :stream stream)))
 627           (when (single-escape-p char)
 628             (setq char (read-char stream nil :eof))
 629             (if (eq char :eof)
 630                 (error 'end-of-file :stream stream)))
 631           (ouch-read-buffer char))))
 632   (read-buffer-to-string))
 633
 634 (defun read-right-paren (stream ignore)
 635   (declare (ignore ignore))
 636   (%reader-error stream "unmatched close parenthesis"))
 637
 638 ;;; Read from the stream up to the next delimiter. Leave the resulting
 639 ;;; token in *READ-BUFFER*, and return two values:
 640 ;;; -- a list of the escaped character positions, and
 641 ;;; -- The position of the first package delimiter (or NIL).
 642 (defun internal-read-extended-token (stream firstchar escape-firstchar)
 643   (reset-read-buffer)
 644   (let ((escapes '()))
 645     (when escape-firstchar
 646       (push *ouch-ptr* escapes)
 647       (ouch-read-buffer firstchar)
 648       (setq firstchar (read-char stream nil *eof-object*)))
 649   (do ((char firstchar (read-char stream nil *eof-object*))
 650        (colon nil))
 651       ((cond ((eofp char) t)
 652              ((token-delimiterp char)
 653               (unread-char char stream)
 654               t)
 655              (t nil))
 656        (values escapes colon))
 657     (cond ((single-escape-p char)
 658            ;; It can't be a number, even if it's 1\23.
 659            ;; Read next char here, so it won't be casified.
 660            (push *ouch-ptr* escapes)
 661            (let ((nextchar (read-char stream nil *eof-object*)))
 662              (if (eofp nextchar)
 663                  (reader-eof-error stream "after escape character")
 664                  (ouch-read-buffer nextchar))))
 665           ((multiple-escape-p char)
 666            ;; Read to next multiple-escape, escaping single chars
 667            ;; along the way.
 668            (loop
 669              (let ((ch (read-char stream nil *eof-object*)))
 670                (cond
 671                 ((eofp ch)
 672                  (reader-eof-error stream "inside extended token"))
 673                 ((multiple-escape-p ch) (return))
 674                 ((single-escape-p ch)
 675                  (let ((nextchar (read-char stream nil *eof-object*)))
 676                    (cond ((eofp nextchar)
 677                           (reader-eof-error stream "after escape character"))
 678                          (t
 679                           (push *ouch-ptr* escapes)
 680                           (ouch-read-buffer nextchar)))))
 681                 (t
 682                  (push *ouch-ptr* escapes)
 683                  (ouch-read-buffer ch))))))
 684           (t
 685            (when (and (constituentp char)
 686                       (eql (get-constituent-trait char)
 687                            +char-attr-package-delimiter+)
 688                       (not colon))
 689              (setq colon *ouch-ptr*))
 690            (ouch-read-buffer char))))))
 691 \f
 692 ;;;; character classes
 693
 694 ;;; Return the character class for CHAR.
 695 ;;;
 696 ;;; FIXME: why aren't these ATT-getting forms using GET-CAT-ENTRY?
 697 ;;; Because we've cached the readtable tables?
 698 (defmacro char-class (char attarray atthash)
 699   `(let ((att (if (typep ,char 'base-char)
 700                   (aref ,attarray (char-code ,char))
 701                   (gethash ,char ,atthash +char-attr-constituent+))))
 702      (declare (fixnum att))
 703      (cond
 704        ((<= att +char-attr-terminating-macro+) +char-attr-delimiter+)
 705        ((< att +char-attr-constituent+) att)
 706        (t (setf att (get-constituent-trait ,char))
 707           (if (= att +char-attr-invalid+)
 708               (%reader-error stream "invalid constituent")
 709               att)))))
 710
 711 ;;; Return the character class for CHAR, which might be part of a
 712 ;;; rational number.
 713 (defmacro char-class2 (char attarray atthash)
 714   `(let ((att (if (typep ,char 'base-char)
 715                   (aref ,attarray (char-code ,char))
 716                   (gethash ,char ,atthash +char-attr-constituent+))))
 717      (declare (fixnum att))
 718      (cond
 719        ((<= att +char-attr-terminating-macro+) +char-attr-delimiter+)
 720        ((< att +char-attr-constituent+) att)
 721        (t (setf att (get-constituent-trait ,char))
 722           (cond
 723             ((digit-char-p ,char *read-base*) +char-attr-constituent-digit+)
 724             ((= att +char-attr-constituent-digit+) +char-attr-constituent+)
 725             ((= att +char-attr-invalid+)
 726              (%reader-error stream "invalid constituent"))
 727             (t att))))))
 728
 729 ;;; Return the character class for a char which might be part of a
 730 ;;; rational or floating number. (Assume that it is a digit if it
 731 ;;; could be.)
 732 (defmacro char-class3 (char attarray atthash)
 733   `(let ((att (if (typep ,char 'base-char)
 734                   (aref ,attarray (char-code ,char))
 735                   (gethash ,char ,atthash +char-attr-constituent+))))
 736      (declare (fixnum att))
 737      (cond
 738        ((<= att +char-attr-terminating-macro+) +char-attr-delimiter+)
 739        ((< att +char-attr-constituent+) att)
 740        (t (setf att (get-constituent-trait ,char))
 741           (when possibly-rational
 742             (setq possibly-rational
 743                   (or (digit-char-p ,char *read-base*)
 744                       (= att +char-attr-constituent-slash+))))
 745           (when possibly-float
 746             (setq possibly-float
 747                   (or (digit-char-p ,char 10)
 748                       (= att +char-attr-constituent-dot+))))
 749           (cond
 750             ((digit-char-p ,char (max *read-base* 10))
 751              (if (digit-char-p ,char *read-base*)
 752                  (if (= att +char-attr-constituent-expt+)
 753                      +char-attr-constituent-digit-or-expt+
 754                      +char-attr-constituent-digit+)
 755                  +char-attr-constituent-decimal-digit+))
 756             ((= att +char-attr-invalid+)
 757              (%reader-error stream "invalid constituent"))
 758             (t att))))))
 759 \f
 760 ;;;; token fetching
 761
 762 (defvar *read-suppress* nil
 763   #!+sb-doc
 764   "Suppress most interpreting in the reader when T.")
 765
 766 (defvar *read-base* 10
 767   #!+sb-doc
 768   "the radix that Lisp reads numbers in")
 769 (declaim (type (integer 2 36) *read-base*))
 770
 771 ;;; Modify the read buffer according to READTABLE-CASE, ignoring
 772 ;;; ESCAPES. ESCAPES is a list of the escaped indices, in reverse
 773 ;;; order.
 774 (defun casify-read-buffer (escapes)
 775   (let ((case (readtable-case *readtable*)))
 776     (cond
 777      ((and (null escapes) (eq case :upcase))
 778       ;; Pull the special variable access out of the loop.
 779       (let ((buffer *read-buffer*))
 780         (dotimes (i *ouch-ptr*)
 781           (declare (optimize (sb!c::insert-array-bounds-checks 0)))
 782           (setf (schar buffer i) (char-upcase (schar buffer i))))))
 783      ((eq case :preserve))
 784      (t
 785       (macrolet ((skip-esc (&body body)
 786                    `(do ((i (1- *ouch-ptr*) (1- i))
 787                          (buffer *read-buffer*)
 788                          (escapes escapes))
 789                         ((minusp i))
 790                       (declare (fixnum i)
 791                                (optimize (sb!c::insert-array-bounds-checks 0)))
 792                       (when (or (null escapes)
 793                                 (let ((esc (first escapes)))
 794                                   (declare (fixnum esc))
 795                                   (cond ((< esc i) t)
 796                                         (t
 797                                          (aver (= esc i))
 798                                          (pop escapes)
 799                                          nil))))
 800                         (let ((ch (schar buffer i)))
 801                           ,@body)))))
 802         (flet ((lower-em ()
 803                  (skip-esc (setf (schar buffer i) (char-downcase ch))))
 804                (raise-em ()
 805                  (skip-esc (setf (schar buffer i) (char-upcase ch)))))
 806           (ecase case
 807             (:upcase (raise-em))
 808             (:downcase (lower-em))
 809             (:invert
 810              (let ((all-upper t)
 811                    (all-lower t))
 812                (skip-esc
 813                  (when (both-case-p ch)
 814                    (if (upper-case-p ch)
 815                        (setq all-lower nil)
 816                        (setq all-upper nil))))
 817                (cond (all-lower (raise-em))
 818                      (all-upper (lower-em))))))))))))
 819
 820 (defun read-token (stream firstchar)
 821   #!+sb-doc
 822   "This function is just an fsm that recognizes numbers and symbols."
 823   ;; Check explicitly whether FIRSTCHAR has an entry for
 824   ;; NON-TERMINATING in CHARACTER-ATTRIBUTE-TABLE and
 825   ;; READ-DOT-NUMBER-SYMBOL in CMT. Report an error if these are
 826   ;; violated. (If we called this, we want something that is a
 827   ;; legitimate token!) Read in the longest possible string satisfying
 828   ;; the Backus-Naur form for "unqualified-token". Leave the result in
 829   ;; the *READ-BUFFER*. Return next char after token (last char read).
 830   (when *read-suppress*
 831     (internal-read-extended-token stream firstchar nil)
 832     (return-from read-token nil))
 833   (let ((attribute-array (character-attribute-array *readtable*))
 834         (attribute-hash-table (character-attribute-hash-table *readtable*))
 835         (package-designator nil)
 836         (colons 0)
 837         (possibly-rational t)
 838         (seen-digit-or-expt nil)
 839         (possibly-float t)
 840         (was-possibly-float nil)
 841         (escapes ())
 842         (seen-multiple-escapes nil))
 843     (reset-read-buffer)
 844     (prog ((char firstchar))
 845       (case (char-class3 char attribute-array attribute-hash-table)
 846         (#.+char-attr-constituent-sign+ (go SIGN))
 847         (#.+char-attr-constituent-digit+ (go LEFTDIGIT))
 848         (#.+char-attr-constituent-digit-or-expt+
 849          (setq seen-digit-or-expt t)
 850          (go LEFTDIGIT))
 851         (#.+char-attr-constituent-decimal-digit+ (go LEFTDECIMALDIGIT))
 852         (#.+char-attr-constituent-dot+ (go FRONTDOT))
 853         (#.+char-attr-single-escape+ (go SINGLE-ESCAPE))
 854         (#.+char-attr-package-delimiter+ (go COLON))
 855         (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
 856         (#.+char-attr-invalid+ (%reader-error stream "invalid constituent"))
 857         ;; can't have eof, whitespace, or terminating macro as first char!
 858         (t (go SYMBOL)))
 859      SIGN ; saw "sign"
 860       (ouch-read-buffer char)
 861       (setq char (read-char stream nil nil))
 862       (unless char (go RETURN-SYMBOL))
 863       (setq possibly-rational t
 864             possibly-float t)
 865       (case (char-class3 char attribute-array attribute-hash-table)
 866         (#.+char-attr-constituent-digit+ (go LEFTDIGIT))
 867         (#.+char-attr-constituent-digit-or-expt+
 868          (setq seen-digit-or-expt t)
 869          (go LEFTDIGIT))
 870         (#.+char-attr-constituent-decimal-digit+ (go LEFTDECIMALDIGIT))
 871         (#.+char-attr-constituent-dot+ (go SIGNDOT))
 872         (#.+char-attr-single-escape+ (go SINGLE-ESCAPE))
 873         (#.+char-attr-package-delimiter+ (go COLON))
 874         (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
 875         (#.+char-attr-delimiter+ (unread-char char stream) (go RETURN-SYMBOL))
 876         (t (go SYMBOL)))
 877      LEFTDIGIT ; saw "[sign] {digit}+"
 878       (ouch-read-buffer char)
 879       (setq char (read-char stream nil nil))
 880       (unless char (return (make-integer)))
 881       (setq was-possibly-float possibly-float)
 882       (case (char-class3 char attribute-array attribute-hash-table)
 883         (#.+char-attr-constituent-digit+ (go LEFTDIGIT))
 884         (#.+char-attr-constituent-decimal-digit+ (if possibly-float
 885                                                      (go LEFTDECIMALDIGIT)
 886                                                      (go SYMBOL)))
 887         (#.+char-attr-constituent-dot+ (if possibly-float
 888                                            (go MIDDLEDOT)
 889                                            (go SYMBOL)))
 890         (#.+char-attr-constituent-digit-or-expt+
 891          (if (or seen-digit-or-expt (not was-possibly-float))
 892              (progn (setq seen-digit-or-expt t) (go LEFTDIGIT))
 893              (progn (setq seen-digit-or-expt t) (go LEFTDIGIT-OR-EXPT))))
 894         (#.+char-attr-constituent-expt+
 895          (if was-possibly-float
 896              (go EXPONENT)
 897              (go SYMBOL)))
 898         (#.+char-attr-constituent-slash+ (if possibly-rational
 899                                              (go RATIO)
 900                                              (go SYMBOL)))
 901         (#.+char-attr-delimiter+ (unread-char char stream)
 902                                  (return (make-integer)))
 903         (#.+char-attr-single-escape+ (go SINGLE-ESCAPE))
 904         (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
 905         (#.+char-attr-package-delimiter+ (go COLON))
 906         (t (go SYMBOL)))
 907      LEFTDIGIT-OR-EXPT
 908       (ouch-read-buffer char)
 909       (setq char (read-char stream nil nil))
 910       (unless char (return (make-integer)))
 911       (case (char-class3 char attribute-array attribute-hash-table)
 912         (#.+char-attr-constituent-digit+ (go LEFTDIGIT))
 913         (#.+char-attr-constituent-decimal-digit+ (bug "impossible!"))
 914         (#.+char-attr-constituent-dot+ (go SYMBOL))
 915         (#.+char-attr-constituent-digit-or-expt+ (go LEFTDIGIT))
 916         (#.+char-attr-constituent-expt+ (go SYMBOL))
 917         (#.+char-attr-constituent-sign+ (go EXPTSIGN))
 918         (#.+char-attr-constituent-slash+ (if possibly-rational
 919                                              (go RATIO)
 920                                              (go SYMBOL)))
 921         (#.+char-attr-delimiter+ (unread-char char stream)
 922                                  (return (make-integer)))
 923         (#.+char-attr-single-escape+ (go SINGLE-ESCAPE))
 924         (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
 925         (#.+char-attr-package-delimiter+ (go COLON))
 926         (t (go SYMBOL)))
 927      LEFTDECIMALDIGIT ; saw "[sign] {decimal-digit}+"
 928       (aver possibly-float)
 929       (ouch-read-buffer char)
 930       (setq char (read-char stream nil nil))
 931       (unless char (go RETURN-SYMBOL))
 932       (case (char-class char attribute-array attribute-hash-table)
 933         (#.+char-attr-constituent-digit+ (go LEFTDECIMALDIGIT))
 934         (#.+char-attr-constituent-dot+ (go MIDDLEDOT))
 935         (#.+char-attr-constituent-expt+ (go EXPONENT))
 936         (#.+char-attr-constituent-slash+ (aver (not possibly-rational))
 937                                          (go SYMBOL))
 938         (#.+char-attr-delimiter+ (unread-char char stream)
 939                                  (go RETURN-SYMBOL))
 940         (#.+char-attr-single-escape+ (go SINGLE-ESCAPE))
 941         (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
 942         (#.+char-attr-package-delimiter+ (go COLON))
 943         (t (go SYMBOL)))
 944      MIDDLEDOT ; saw "[sign] {digit}+ dot"
 945       (ouch-read-buffer char)
 946       (setq char (read-char stream nil nil))
 947       (unless char (return (let ((*read-base* 10))
 948                              (make-integer))))
 949       (case (char-class char attribute-array attribute-hash-table)
 950         (#.+char-attr-constituent-digit+ (go RIGHTDIGIT))
 951         (#.+char-attr-constituent-expt+ (go EXPONENT))
 952         (#.+char-attr-delimiter+
 953          (unread-char char stream)
 954          (return (let ((*read-base* 10))
 955                    (make-integer))))
 956         (#.+char-attr-single-escape+ (go SINGLE-ESCAPE))
 957         (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
 958         (#.+char-attr-package-delimiter+ (go COLON))
 959         (t (go SYMBOL)))
 960      RIGHTDIGIT ; saw "[sign] {decimal-digit}* dot {digit}+"
 961       (ouch-read-buffer char)
 962       (setq char (read-char stream nil nil))
 963       (unless char (return (make-float stream)))
 964       (case (char-class char attribute-array attribute-hash-table)
 965         (#.+char-attr-constituent-digit+ (go RIGHTDIGIT))
 966         (#.+char-attr-constituent-expt+ (go EXPONENT))
 967         (#.+char-attr-delimiter+
 968          (unread-char char stream)
 969          (return (make-float stream)))
 970         (#.+char-attr-single-escape+ (go SINGLE-ESCAPE))
 971         (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
 972         (#.+char-attr-package-delimiter+ (go COLON))
 973         (t (go SYMBOL)))
 974      SIGNDOT ; saw "[sign] dot"
 975       (ouch-read-buffer char)
 976       (setq char (read-char stream nil nil))
 977       (unless char (go RETURN-SYMBOL))
 978       (case (char-class char attribute-array attribute-hash-table)
 979         (#.+char-attr-constituent-digit+ (go RIGHTDIGIT))
 980         (#.+char-attr-delimiter+ (unread-char char stream) (go RETURN-SYMBOL))
 981         (#.+char-attr-single-escape+ (go SINGLE-ESCAPE))
 982         (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
 983         (t (go SYMBOL)))
 984      FRONTDOT ; saw "dot"
 985       (ouch-read-buffer char)
 986       (setq char (read-char stream nil nil))
 987       (unless char (%reader-error stream "dot context error"))
 988       (case (char-class char attribute-array attribute-hash-table)
 989         (#.+char-attr-constituent-digit+ (go RIGHTDIGIT))
 990         (#.+char-attr-constituent-dot+ (go DOTS))
 991         (#.+char-attr-delimiter+  (%reader-error stream "dot context error"))
 992         (#.+char-attr-single-escape+ (go SINGLE-ESCAPE))
 993         (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
 994         (#.+char-attr-package-delimiter+ (go COLON))
 995         (t (go SYMBOL)))
 996      EXPONENT
 997       (ouch-read-buffer char)
 998       (setq char (read-char stream nil nil))
 999       (unless char (go RETURN-SYMBOL))
1000       (setq possibly-float t)
1001       (case (char-class char attribute-array attribute-hash-table)
1002         (#.+char-attr-constituent-sign+ (go EXPTSIGN))
1003         (#.+char-attr-constituent-digit+ (go EXPTDIGIT))
1004         (#.+char-attr-delimiter+ (unread-char char stream) (go RETURN-SYMBOL))
1005         (#.+char-attr-single-escape+ (go SINGLE-ESCAPE))
1006         (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
1007         (#.+char-attr-package-delimiter+ (go COLON))
1008         (t (go SYMBOL)))
1009      EXPTSIGN ; got to EXPONENT, and saw a sign character
1010       (ouch-read-buffer char)
1011       (setq char (read-char stream nil nil))
1012       (unless char (go RETURN-SYMBOL))
1013       (case (char-class char attribute-array attribute-hash-table)
1014         (#.+char-attr-constituent-digit+ (go EXPTDIGIT))
1015         (#.+char-attr-delimiter+ (unread-char char stream) (go RETURN-SYMBOL))
1016         (#.+char-attr-single-escape+ (go SINGLE-ESCAPE))
1017         (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
1018         (#.+char-attr-package-delimiter+ (go COLON))
1019         (t (go SYMBOL)))
1020      EXPTDIGIT ; got to EXPONENT, saw "[sign] {digit}+"
1021       (ouch-read-buffer char)
1022       (setq char (read-char stream nil nil))
1023       (unless char (return (make-float stream)))
1024       (case (char-class char attribute-array attribute-hash-table)
1025         (#.+char-attr-constituent-digit+ (go EXPTDIGIT))
1026         (#.+char-attr-delimiter+
1027          (unread-char char stream)
1028          (return (make-float stream)))
1029         (#.+char-attr-single-escape+ (go SINGLE-ESCAPE))
1030         (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
1031         (#.+char-attr-package-delimiter+ (go COLON))
1032         (t (go SYMBOL)))
1033      RATIO ; saw "[sign] {digit}+ slash"
1034       (ouch-read-buffer char)
1035       (setq char (read-char stream nil nil))
1036       (unless char (go RETURN-SYMBOL))
1037       (case (char-class2 char attribute-array attribute-hash-table)
1038         (#.+char-attr-constituent-digit+ (go RATIODIGIT))
1039         (#.+char-attr-delimiter+ (unread-char char stream) (go RETURN-SYMBOL))
1040         (#.+char-attr-single-escape+ (go SINGLE-ESCAPE))
1041         (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
1042         (#.+char-attr-package-delimiter+ (go COLON))
1043         (t (go SYMBOL)))
1044      RATIODIGIT ; saw "[sign] {digit}+ slash {digit}+"
1045       (ouch-read-buffer char)
1046       (setq char (read-char stream nil nil))
1047       (unless char (return (make-ratio stream)))
1048       (case (char-class2 char attribute-array attribute-hash-table)
1049         (#.+char-attr-constituent-digit+ (go RATIODIGIT))
1050         (#.+char-attr-delimiter+
1051          (unread-char char stream)
1052          (return (make-ratio stream)))
1053         (#.+char-attr-single-escape+ (go SINGLE-ESCAPE))
1054         (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
1055         (#.+char-attr-package-delimiter+ (go COLON))
1056         (t (go SYMBOL)))
1057      DOTS ; saw "dot {dot}+"
1058       (ouch-read-buffer char)
1059       (setq char (read-char stream nil nil))
1060       (unless char (%reader-error stream "too many dots"))
1061       (case (char-class char attribute-array attribute-hash-table)
1062         (#.+char-attr-constituent-dot+ (go DOTS))
1063         (#.+char-attr-delimiter+
1064          (unread-char char stream)
1065          (%reader-error stream "too many dots"))
1066         (#.+char-attr-single-escape+ (go SINGLE-ESCAPE))
1067         (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
1068         (#.+char-attr-package-delimiter+ (go COLON))
1069         (t (go SYMBOL)))
1070      SYMBOL ; not a dot, dots, or number
1071       (let ((stream (in-synonym-of stream)))
1072         (if (ansi-stream-p stream)
1073             (prepare-for-fast-read-char stream
1074               (prog ()
1075                SYMBOL-LOOP
1076                (ouch-read-buffer char)
1077                (setq char (fast-read-char nil nil))
1078                (unless char (go RETURN-SYMBOL))
1079                (case (char-class char attribute-array attribute-hash-table)
1080                  (#.+char-attr-single-escape+ (done-with-fast-read-char)
1081                                               (go SINGLE-ESCAPE))
1082                  (#.+char-attr-delimiter+ (done-with-fast-read-char)
1083                                           (unread-char char stream)
1084                                           (go RETURN-SYMBOL))
1085                  (#.+char-attr-multiple-escape+ (done-with-fast-read-char)
1086                                                 (go MULT-ESCAPE))
1087                  (#.+char-attr-package-delimiter+ (done-with-fast-read-char)
1088                                                   (go COLON))
1089                  (t (go SYMBOL-LOOP)))))
1090             ;; CLOS stream
1091             (prog ()
1092              SYMBOL-LOOP
1093              (ouch-read-buffer char)
1094              (setq char (read-char stream nil :eof))
1095              (when (eq char :eof) (go RETURN-SYMBOL))
1096              (case (char-class char attribute-array attribute-hash-table)
1097                (#.+char-attr-single-escape+ (go SINGLE-ESCAPE))
1098                (#.+char-attr-delimiter+ (unread-char char stream)
1099                             (go RETURN-SYMBOL))
1100                (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
1101                (#.+char-attr-package-delimiter+ (go COLON))
1102                (t (go SYMBOL-LOOP))))))
1103      SINGLE-ESCAPE ; saw a single-escape
1104       ;; Don't put the escape character in the read buffer.
1105       ;; READ-NEXT CHAR, put in buffer (no case conversion).
1106       (let ((nextchar (read-char stream nil nil)))
1107         (unless nextchar
1108           (reader-eof-error stream "after single-escape character"))
1109         (push *ouch-ptr* escapes)
1110         (ouch-read-buffer nextchar))
1111       (setq char (read-char stream nil nil))
1112       (unless char (go RETURN-SYMBOL))
1113       (case (char-class char attribute-array attribute-hash-table)
1114         (#.+char-attr-delimiter+ (unread-char char stream) (go RETURN-SYMBOL))
1115         (#.+char-attr-single-escape+ (go SINGLE-ESCAPE))
1116         (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
1117         (#.+char-attr-package-delimiter+ (go COLON))
1118         (t (go SYMBOL)))
1119       MULT-ESCAPE
1120       (setq seen-multiple-escapes t)
1121       (do ((char (read-char stream t) (read-char stream t)))
1122           ((multiple-escape-p char))
1123         (if (single-escape-p char) (setq char (read-char stream t)))
1124         (push *ouch-ptr* escapes)
1125         (ouch-read-buffer char))
1126       (setq char (read-char stream nil nil))
1127       (unless char (go RETURN-SYMBOL))
1128       (case (char-class char attribute-array attribute-hash-table)
1129         (#.+char-attr-delimiter+ (unread-char char stream) (go RETURN-SYMBOL))
1130         (#.+char-attr-single-escape+ (go SINGLE-ESCAPE))
1131         (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
1132         (#.+char-attr-package-delimiter+ (go COLON))
1133         (t (go SYMBOL)))
1134       COLON
1135       (casify-read-buffer escapes)
1136       (unless (zerop colons)
1137         (%reader-error stream "too many colons in ~S"
1138                       (read-buffer-to-string)))
1139       (setq colons 1)
1140       (setq package-designator
1141             (if (plusp *ouch-ptr*)
1142                 ;; FIXME: It seems inefficient to cons up a package
1143                 ;; designator string every time we read a symbol with an
1144                 ;; explicit package prefix. Perhaps we could implement
1145                 ;; a FIND-PACKAGE* function analogous to INTERN*
1146                 ;; and friends?
1147                 (read-buffer-to-string)
1148                 (if seen-multiple-escapes
1149                     (read-buffer-to-string)
1150                     *keyword-package*)))
1151       (reset-read-buffer)
1152       (setq escapes ())
1153       (setq char (read-char stream nil nil))
1154       (unless char (reader-eof-error stream "after reading a colon"))
1155       (case (char-class char attribute-array attribute-hash-table)
1156         (#.+char-attr-delimiter+
1157          (unread-char char stream)
1158          (%reader-error stream
1159                         "illegal terminating character after a colon: ~S"
1160                         char))
1161         (#.+char-attr-single-escape+ (go SINGLE-ESCAPE))
1162         (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
1163         (#.+char-attr-package-delimiter+ (go INTERN))
1164         (t (go SYMBOL)))
1165       INTERN
1166       (setq colons 2)
1167       (setq char (read-char stream nil nil))
1168       (unless char
1169         (reader-eof-error stream "after reading a colon"))
1170       (case (char-class char attribute-array attribute-hash-table)
1171         (#.+char-attr-delimiter+
1172          (unread-char char stream)
1173          (%reader-error stream
1174                         "illegal terminating character after a colon: ~S"
1175                         char))
1176         (#.+char-attr-single-escape+ (go SINGLE-ESCAPE))
1177         (#.+char-attr-multiple-escape+ (go MULT-ESCAPE))
1178         (#.+char-attr-package-delimiter+
1179          (%reader-error stream
1180                         "too many colons after ~S name"
1181                         package-designator))
1182         (t (go SYMBOL)))
1183       RETURN-SYMBOL
1184       (casify-read-buffer escapes)
1185       (let ((found (if package-designator
1186                        (find-package package-designator)
1187                        (sane-package))))
1188         (unless found
1189           (error 'reader-package-error :stream stream
1190                  :format-arguments (list package-designator)
1191                  :format-control "package ~S not found"))
1192
1193         (if (or (zerop colons) (= colons 2) (eq found *keyword-package*))
1194             (return (intern* *read-buffer* *ouch-ptr* found))
1195             (multiple-value-bind (symbol test)
1196                 (find-symbol* *read-buffer* *ouch-ptr* found)
1197               (when (eq test :external) (return symbol))
1198               (let ((name (read-buffer-to-string)))
1199                 (with-simple-restart (continue "Use symbol anyway.")
1200                   (error 'reader-package-error :stream stream
1201                          :format-arguments (list name (package-name found))
1202                          :format-control
1203                          (if test
1204                              "The symbol ~S is not external in the ~A package."
1205                              "Symbol ~S not found in the ~A package.")))
1206                 (return (intern name found)))))))))
1207
1208 ;;; for semi-external use:
1209 ;;;
1210 ;;; For semi-external use: Return 3 values: the string for the token,
1211 ;;; a flag for whether there was an escape char, and the position of
1212 ;;; any package delimiter.
1213 (defun read-extended-token (stream &optional (*readtable* *readtable*))
1214   (let ((first-char (read-char stream nil nil t)))
1215     (cond (first-char
1216            (multiple-value-bind (escapes colon)
1217                (internal-read-extended-token stream first-char nil)
1218              (casify-read-buffer escapes)
1219              (values (read-buffer-to-string) (not (null escapes)) colon)))
1220           (t
1221            (values "" nil nil)))))
1222
1223 ;;; for semi-external use:
1224 ;;;
1225 ;;; Read an extended token with the first character escaped. Return
1226 ;;; the string for the token.
1227 (defun read-extended-token-escaped (stream &optional (*readtable* *readtable*))
1228   (let ((first-char (read-char stream nil nil)))
1229     (cond (first-char
1230             (let ((escapes (internal-read-extended-token stream first-char t)))
1231               (casify-read-buffer escapes)
1232               (read-buffer-to-string)))
1233           (t
1234             (reader-eof-error stream "after escape")))))
1235 \f
1236 ;;;; number-reading functions
1237
1238 (defmacro digit* nil
1239   `(do ((ch char (inch-read-buffer)))
1240        ((or (eofp ch) (not (digit-char-p ch))) (setq char ch))
1241      ;; Report if at least one digit is seen.
1242      (setq one-digit t)))
1243
1244 (defmacro exponent-letterp (letter)
1245   `(memq ,letter '(#\E #\S #\F #\L #\D #\e #\s #\f #\l #\d)))
1246
1247 ;;; FIXME: It would be cleaner to have these generated automatically
1248 ;;; by compile-time code instead of having them hand-created like
1249 ;;; this. The !COLD-INIT-INTEGER-READER code below should be resurrected
1250 ;;; and tested.
1251 (defvar *integer-reader-safe-digits*
1252   #(nil nil
1253     26 17 13 11 10 9 8 8 8 7 7 7 7 6 6 6 6 6 6 6 6 5 5 5 5 5 5 5 5 5 5 5 5 5 5)
1254   #!+sb-doc
1255   "the mapping of base to 'safe' number of digits to read for a fixnum")
1256 (defvar *integer-reader-base-power*
1257   #(nil nil
1258     67108864 129140163 67108864 48828125 60466176 40353607
1259     16777216 43046721 100000000 19487171 35831808 62748517 105413504 11390625
1260     16777216 24137569 34012224 47045881 64000000 85766121 113379904 6436343
1261     7962624 9765625 11881376 14348907 17210368 20511149 24300000 28629151
1262     33554432 39135393 45435424 52521875 60466176)
1263   #!+sb-doc
1264   "the largest fixnum power of the base for MAKE-INTEGER")
1265 (declaim (simple-vector *integer-reader-safe-digits*
1266                         *integer-reader-base-power*))
1267 #|
1268 (defun !cold-init-integer-reader ()
1269   (do ((base 2 (1+ base)))
1270       ((> base 36))
1271     (let ((digits
1272           (do ((fix (truncate most-positive-fixnum base)
1273                     (truncate fix base))
1274                (digits 0 (1+ digits)))
1275               ((zerop fix) digits))))
1276       (setf (aref *integer-reader-safe-digits* base)
1277             digits
1278             (aref *integer-reader-base-power* base)
1279             (expt base digits)))))
1280 |#
1281
1282 (defun make-integer ()
1283   #!+sb-doc
1284   "Minimizes bignum-fixnum multiplies by reading a 'safe' number of digits,
1285   then multiplying by a power of the base and adding."
1286   (let* ((base *read-base*)
1287          (digits-per (aref *integer-reader-safe-digits* base))
1288          (base-power (aref *integer-reader-base-power* base))
1289          (negativep nil)
1290          (number 0))
1291     (declare (type index digits-per base-power))
1292     (read-unwind-read-buffer)
1293     (let ((char (inch-read-buffer)))
1294       (cond ((char= char #\-)
1295              (setq negativep t))
1296             ((char= char #\+))
1297             (t (unread-buffer))))
1298     (loop
1299      (let ((num 0))
1300        (declare (type index num))
1301        (dotimes (digit digits-per)
1302          (let* ((ch (inch-read-buffer)))
1303            (cond ((or (eofp ch) (char= ch #\.))
1304                   (return-from make-integer
1305                                (let ((res
1306                                       (if (zerop number) num
1307                                           (+ num (* number
1308                                                     (expt base digit))))))
1309                                  (if negativep (- res) res))))
1310                  (t (setq num (+ (digit-char-p ch base)
1311                                  (the index (* num base))))))))
1312        (setq number (+ num (* number base-power)))))))
1313
1314 (defun make-float (stream)
1315   ;; Assume that the contents of *read-buffer* are a legal float, with nothing
1316   ;; else after it.
1317   (read-unwind-read-buffer)
1318   (let ((negative-fraction nil)
1319         (number 0)
1320         (divisor 1)
1321         (negative-exponent nil)
1322         (exponent 0)
1323         (float-char ())
1324         (char (inch-read-buffer)))
1325     (if (cond ((char= char #\+) t)
1326               ((char= char #\-) (setq negative-fraction t)))
1327         ;; Flush it.
1328         (setq char (inch-read-buffer)))
1329     ;; Read digits before the dot.
1330     (do* ((ch char (inch-read-buffer))
1331           (dig (digit-char-p ch) (digit-char-p ch)))
1332          ((not dig) (setq char ch))
1333       (setq number (+ (* number 10) dig)))
1334     ;; Deal with the dot, if it's there.
1335     (when (char= char #\.)
1336       (setq char (inch-read-buffer))
1337       ;; Read digits after the dot.
1338       (do* ((ch char (inch-read-buffer))
1339             (dig (and (not (eofp ch)) (digit-char-p ch))
1340                  (and (not (eofp ch)) (digit-char-p ch))))
1341            ((not dig) (setq char ch))
1342         (setq divisor (* divisor 10))
1343         (setq number (+ (* number 10) dig))))
1344     ;; Is there an exponent letter?
1345     (cond ((eofp char)
1346            ;; If not, we've read the whole number.
1347            (let ((num (make-float-aux number divisor
1348                                       *read-default-float-format*
1349                                       stream)))
1350              (return-from make-float (if negative-fraction (- num) num))))
1351           ((exponent-letterp char)
1352            (setq float-char char)
1353            ;; Build exponent.
1354            (setq char (inch-read-buffer))
1355            ;; Check leading sign.
1356            (if (cond ((char= char #\+) t)
1357                      ((char= char #\-) (setq negative-exponent t)))
1358                ;; Flush sign.
1359                (setq char (inch-read-buffer)))
1360            ;; Read digits for exponent.
1361            (do* ((ch char (inch-read-buffer))
1362                  (dig (and (not (eofp ch)) (digit-char-p ch))
1363                       (and (not (eofp ch)) (digit-char-p ch))))
1364                 ((not dig)
1365                  (setq exponent (if negative-exponent (- exponent) exponent)))
1366              (setq exponent (+ (* exponent 10) dig)))
1367            ;; Generate and return the float, depending on FLOAT-CHAR:
1368            (let* ((float-format (case (char-upcase float-char)
1369                                   (#\E *read-default-float-format*)
1370                                   (#\S 'short-float)
1371                                   (#\F 'single-float)
1372                                   (#\D 'double-float)
1373                                   (#\L 'long-float)))
1374                   (result (make-float-aux (* (expt 10 exponent) number)
1375                                           divisor float-format stream)))
1376              (return-from make-float
1377                (if negative-fraction (- result) result))))
1378           (t (bug "bad fallthrough in floating point reader")))))
1379
1380 (defun make-float-aux (number divisor float-format stream)
1381   (handler-case
1382       (coerce (/ number divisor) float-format)
1383     (type-error (c)
1384       (error 'reader-impossible-number-error
1385              :error c :stream stream
1386              :format-control "failed to build float"))))
1387
1388 (defun make-ratio (stream)
1389   ;; Assume *READ-BUFFER* contains a legal ratio. Build the number from
1390   ;; the string.
1391   ;;
1392   ;; Look for optional "+" or "-".
1393   (let ((numerator 0) (denominator 0) (char ()) (negative-number nil))
1394     (read-unwind-read-buffer)
1395     (setq char (inch-read-buffer))
1396     (cond ((char= char #\+)
1397            (setq char (inch-read-buffer)))
1398           ((char= char #\-)
1399            (setq char (inch-read-buffer))
1400            (setq negative-number t)))
1401     ;; Get numerator.
1402     (do* ((ch char (inch-read-buffer))
1403           (dig (digit-char-p ch *read-base*)
1404                (digit-char-p ch *read-base*)))
1405          ((not dig))
1406          (setq numerator (+ (* numerator *read-base*) dig)))
1407     ;; Get denominator.
1408     (do* ((ch (inch-read-buffer) (inch-read-buffer))
1409           (dig ()))
1410          ((or (eofp ch) (not (setq dig (digit-char-p ch *read-base*)))))
1411          (setq denominator (+ (* denominator *read-base*) dig)))
1412     (let ((num (handler-case
1413                    (/ numerator denominator)
1414                  (arithmetic-error (c)
1415                    (error 'reader-impossible-number-error
1416                           :error c :stream stream
1417                           :format-control "failed to build ratio")))))
1418       (if negative-number (- num) num))))
1419 \f
1420 ;;;; cruft for dispatch macros
1421
1422 (defun make-char-dispatch-table ()
1423   (make-hash-table))
1424
1425 (defun dispatch-char-error (stream sub-char ignore)
1426   (declare (ignore ignore))
1427   (if *read-suppress*
1428       (values)
1429       (%reader-error stream "no dispatch function defined for ~S" sub-char)))
1430
1431 (defun make-dispatch-macro-character (char &optional
1432                                            (non-terminating-p nil)
1433                                            (rt *readtable*))
1434   #!+sb-doc
1435   "Cause CHAR to become a dispatching macro character in readtable (which
1436    defaults to the current readtable). If NON-TERMINATING-P, the char will
1437    be non-terminating."
1438   (set-macro-character char #'read-dispatch-char non-terminating-p rt)
1439   (let* ((dalist (dispatch-tables rt))
1440          (dtable (cdr (find char dalist :test #'char= :key #'car))))
1441     (cond (dtable
1442            (error "The dispatch character ~S already exists." char))
1443           (t
1444            (setf (dispatch-tables rt)
1445                  (push (cons char (make-char-dispatch-table)) dalist)))))
1446   t)
1447
1448 (defun set-dispatch-macro-character (disp-char sub-char function
1449                                                &optional (rt *readtable*))
1450   #!+sb-doc
1451   "Cause FUNCTION to be called whenever the reader reads DISP-CHAR
1452    followed by SUB-CHAR."
1453   ;; Get the dispatch char for macro (error if not there), diddle
1454   ;; entry for sub-char.
1455   (when (digit-char-p sub-char)
1456     (error "SUB-CHAR must not be a decimal digit: ~S" sub-char))
1457   (let* ((sub-char (char-upcase sub-char))
1458          (rt (or rt *standard-readtable*))
1459          (dpair (find disp-char (dispatch-tables rt)
1460                       :test #'char= :key #'car)))
1461     (if dpair
1462         (setf (gethash sub-char (cdr dpair)) (coerce function 'function))
1463         (error "~S is not a dispatch char." disp-char))))
1464
1465 (defun get-dispatch-macro-character (disp-char sub-char
1466                                      &optional (rt *readtable*))
1467   #!+sb-doc
1468   "Return the macro character function for SUB-CHAR under DISP-CHAR
1469    or NIL if there is no associated function."
1470   (let* ((sub-char (char-upcase sub-char))
1471          (rt (or rt *standard-readtable*))
1472          (dpair (find disp-char (dispatch-tables rt)
1473                       :test #'char= :key #'car)))
1474     (if dpair
1475         (values (gethash sub-char (cdr dpair)))
1476         (error "~S is not a dispatch char." disp-char))))
1477
1478 (defun read-dispatch-char (stream char)
1479   ;; Read some digits.
1480   (let ((numargp nil)
1481         (numarg 0)
1482         (sub-char ()))
1483     (do* ((ch (read-char stream nil *eof-object*)
1484               (read-char stream nil *eof-object*))
1485           (dig ()))
1486          ((or (eofp ch)
1487               (not (setq dig (digit-char-p ch))))
1488           ;; Take care of the extra char.
1489           (if (eofp ch)
1490               (reader-eof-error stream "inside dispatch character")
1491               (setq sub-char (char-upcase ch))))
1492       (setq numargp t)
1493       (setq numarg (+ (* numarg 10) dig)))
1494     ;; Look up the function and call it.
1495     (let ((dpair (find char (dispatch-tables *readtable*)
1496                        :test #'char= :key #'car)))
1497       (if dpair
1498           (funcall (the function
1499                      (gethash sub-char (cdr dpair) #'dispatch-char-error))
1500                    stream sub-char (if numargp numarg nil))
1501           (%reader-error stream "no dispatch table for dispatch char")))))
1502 \f
1503 ;;;; READ-FROM-STRING
1504
1505 (defun read-from-string (string &optional (eof-error-p t) eof-value
1506                                 &key (start 0) end
1507                                 preserve-whitespace)
1508   #!+sb-doc
1509   "The characters of string are successively given to the lisp reader
1510    and the lisp object built by the reader is returned. Macro chars
1511    will take effect."
1512   (declare (string string))
1513   (with-array-data ((string string :offset-var offset)
1514                     (start start)
1515                     (end (%check-vector-sequence-bounds string start end)))
1516     (let ((stream (make-string-input-stream string start end)))
1517       (values (if preserve-whitespace
1518                   (read-preserving-whitespace stream eof-error-p eof-value)
1519                   (read stream eof-error-p eof-value))
1520               (- (string-input-stream-current stream) offset)))))
1521 \f
1522 ;;;; PARSE-INTEGER
1523
1524 (defun parse-integer (string &key (start 0) end (radix 10) junk-allowed)
1525   #!+sb-doc
1526   "Examine the substring of string delimited by start and end
1527   (default to the beginning and end of the string)  It skips over
1528   whitespace characters and then tries to parse an integer. The
1529   radix parameter must be between 2 and 36."
1530   (macrolet ((parse-error (format-control)
1531                `(error 'simple-parse-error
1532                        :format-control ,format-control
1533                        :format-arguments (list string))))
1534     (with-array-data ((string string :offset-var offset)
1535                       (start start)
1536                       (end (%check-vector-sequence-bounds string start end)))
1537       (let ((index (do ((i start (1+ i)))
1538                        ((= i end)
1539                         (if junk-allowed
1540                             (return-from parse-integer (values nil end))
1541                             (parse-error "no non-whitespace characters in string ~S.")))
1542                      (declare (fixnum i))
1543                      (unless (whitespace[1]p (char string i)) (return i))))
1544             (minusp nil)
1545             (found-digit nil)
1546             (result 0))
1547         (declare (fixnum index))
1548         (let ((char (char string index)))
1549           (cond ((char= char #\-)
1550                  (setq minusp t)
1551                  (incf index))
1552                 ((char= char #\+)
1553                  (incf index))))
1554         (loop
1555          (when (= index end) (return nil))
1556          (let* ((char (char string index))
1557                 (weight (digit-char-p char radix)))
1558            (cond (weight
1559                   (setq result (+ weight (* result radix))
1560                         found-digit t))
1561                  (junk-allowed (return nil))
1562                  ((whitespace[1]p char)
1563                   (loop
1564                    (incf index)
1565                    (when (= index end) (return))
1566                    (unless (whitespace[1]p (char string index))
1567                       (parse-error "junk in string ~S")))
1568                   (return nil))
1569                  (t
1570                   (parse-error "junk in string ~S"))))
1571          (incf index))
1572         (values
1573          (if found-digit
1574              (if minusp (- result) result)
1575              (if junk-allowed
1576                  nil
1577                  (parse-error "no digits in string ~S")))
1578          (- index offset))))))
1579 \f
1580 ;;;; reader initialization code
1581
1582 (defun !reader-cold-init ()
1583   (!cold-init-constituent-trait-table)
1584   (!cold-init-standard-readtable)
1585   ;; FIXME: This was commented out, but should probably be restored.
1586   #+nil (!cold-init-integer-reader))
1587 \f
1588 (def!method print-object ((readtable readtable) stream)
1589   (print-unreadable-object (readtable stream :identity t :type t)))