src/code/late-format.lisp

   1 ;;;; This software is part of the SBCL system. See the README file for
   2 ;;;; more information.
   3 ;;;;
   4 ;;;; This software is derived from the CMU CL system, which was
   5 ;;;; written at Carnegie Mellon University and released into the
   6 ;;;; public domain. The software is in the public domain and is
   7 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
   8 ;;;; files for more information.
   9
  10 (in-package "SB!FORMAT")
  11 \f
  12 (define-condition format-error (error)
  13   ((complaint :reader format-error-complaint :initarg :complaint)
  14    (args :reader format-error-args :initarg :args :initform nil)
  15    (control-string :reader format-error-control-string
  16                    :initarg :control-string
  17                    :initform *default-format-error-control-string*)
  18    (offset :reader format-error-offset :initarg :offset
  19            :initform *default-format-error-offset*)
  20    (print-banner :reader format-error-print-banner :initarg :print-banner
  21                  :initform t))
  22   (:report %print-format-error))
  23
  24 (defun %print-format-error (condition stream)
  25   (format stream
  26           "~:[~;error in format: ~]~
  27                  ~?~@[~%  ~A~%  ~V@T^~]"
  28           (format-error-print-banner condition)
  29           (format-error-complaint condition)
  30           (format-error-args condition)
  31           (format-error-control-string condition)
  32           (format-error-offset condition)))
  33 \f
  34 (def!struct format-directive
  35   (string (missing-arg) :type simple-string)
  36   (start (missing-arg) :type (and unsigned-byte fixnum))
  37   (end (missing-arg) :type (and unsigned-byte fixnum))
  38   (character (missing-arg) :type base-char)
  39   (colonp nil :type (member t nil))
  40   (atsignp nil :type (member t nil))
  41   (params nil :type list))
  42 (def!method print-object ((x format-directive) stream)
  43   (print-unreadable-object (x stream)
  44     (write-string (format-directive-string x)
  45                   stream
  46                   :start (format-directive-start x)
  47                   :end (format-directive-end x))))
  48 \f
  49 ;;;; TOKENIZE-CONTROL-STRING
  50
  51 (defun tokenize-control-string (string)
  52   (declare (simple-string string))
  53   (let ((index 0)
  54         (end (length string))
  55         (result nil))
  56     (loop
  57       (let ((next-directive (or (position #\~ string :start index) end)))
  58         (when (> next-directive index)
  59           (push (subseq string index next-directive) result))
  60         (when (= next-directive end)
  61           (return))
  62         (let ((directive (parse-directive string next-directive)))
  63           (push directive result)
  64           (setf index (format-directive-end directive)))))
  65     (nreverse result)))
  66
  67 (defun parse-directive (string start)
  68   (let ((posn (1+ start)) (params nil) (colonp nil) (atsignp nil)
  69         (end (length string)))
  70     (flet ((get-char ()
  71              (if (= posn end)
  72                  (error 'format-error
  73                         :complaint "String ended before directive was found."
  74                         :control-string string
  75                         :offset start)
  76                  (schar string posn)))
  77            (check-ordering ()
  78              (when (or colonp atsignp)
  79                (error 'format-error
  80                       :complaint "parameters found after #\\: or #\\@ modifier"
  81                       :control-string string
  82                       :offset posn))))
  83       (loop
  84         (let ((char (get-char)))
  85           (cond ((or (char<= #\0 char #\9) (char= char #\+) (char= char #\-))
  86                  (check-ordering)
  87                  (multiple-value-bind (param new-posn)
  88                      (parse-integer string :start posn :junk-allowed t)
  89                    (push (cons posn param) params)
  90                    (setf posn new-posn)
  91                    (case (get-char)
  92                      (#\,)
  93                      ((#\: #\@)
  94                       (decf posn))
  95                      (t
  96                       (return)))))
  97                 ((or (char= char #\v)
  98                      (char= char #\V))
  99                  (check-ordering)
 100                  (push (cons posn :arg) params)
 101                  (incf posn)
 102                  (case (get-char)
 103                    (#\,)
 104                    ((#\: #\@)
 105                     (decf posn))
 106                    (t
 107                     (return))))
 108                 ((char= char #\#)
 109                  (check-ordering)
 110                  (push (cons posn :remaining) params)
 111                  (incf posn)
 112                  (case (get-char)
 113                    (#\,)
 114                    ((#\: #\@)
 115                     (decf posn))
 116                    (t
 117                     (return))))
 118                 ((char= char #\')
 119                  (check-ordering)
 120                  (incf posn)
 121                  (push (cons posn (get-char)) params)
 122                  (incf posn)
 123                  (unless (char= (get-char) #\,)
 124                    (decf posn)))
 125                 ((char= char #\,)
 126                  (check-ordering)
 127                  (push (cons posn nil) params))
 128                 ((char= char #\:)
 129                  (if colonp
 130                      (error 'format-error
 131                             :complaint "too many colons supplied"
 132                             :control-string string
 133                             :offset posn)
 134                      (setf colonp t)))
 135                 ((char= char #\@)
 136                  (if atsignp
 137                      (error 'format-error
 138                             :complaint "too many #\\@ characters supplied"
 139                             :control-string string
 140                             :offset posn)
 141                      (setf atsignp t)))
 142                 (t
 143                  (when (char= (schar string (1- posn)) #\,)
 144                    (check-ordering)
 145                    (push (cons (1- posn) nil) params))
 146                  (return))))
 147         (incf posn))
 148       (let ((char (get-char)))
 149         (when (char= char #\/)
 150           (let ((closing-slash (position #\/ string :start (1+ posn))))
 151             (if closing-slash
 152                 (setf posn closing-slash)
 153                 (error 'format-error
 154                        :complaint "no matching closing slash"
 155                        :control-string string
 156                        :offset posn))))
 157         (make-format-directive
 158          :string string :start start :end (1+ posn)
 159          :character (char-upcase char)
 160          :colonp colonp :atsignp atsignp
 161          :params (nreverse params))))))
 162 \f
 163 ;;;; FORMATTER stuff
 164
 165 (sb!xc:defmacro formatter (control-string)
 166   `#',(%formatter control-string))
 167
 168 (defun %formatter (control-string)
 169   (block nil
 170     (catch 'need-orig-args
 171       (let* ((*simple-args* nil)
 172              (*only-simple-args* t)
 173              (guts (expand-control-string control-string))
 174              (args nil))
 175         (dolist (arg *simple-args*)
 176           (push `(,(car arg)
 177                   (error
 178                    'format-error
 179                    :complaint "required argument missing"
 180                    :control-string ,control-string
 181                    :offset ,(cdr arg)))
 182                 args))
 183         (return `(lambda (stream &optional ,@args &rest args)
 184                    ,guts
 185                    args))))
 186     (let ((*orig-args-available* t)
 187           (*only-simple-args* nil))
 188       `(lambda (stream &rest orig-args)
 189          (let ((args orig-args))
 190            ,(expand-control-string control-string)
 191            args)))))
 192
 193 (defun expand-control-string (string)
 194   (let* ((string (etypecase string
 195                    (simple-string
 196                     string)
 197                    (string
 198                     (coerce string 'simple-string))))
 199          (*default-format-error-control-string* string)
 200          (directives (tokenize-control-string string)))
 201     `(block nil
 202        ,@(expand-directive-list directives))))
 203
 204 (defun expand-directive-list (directives)
 205   (let ((results nil)
 206         (remaining-directives directives))
 207     (loop
 208       (unless remaining-directives
 209         (return))
 210       (multiple-value-bind (form new-directives)
 211           (expand-directive (car remaining-directives)
 212                             (cdr remaining-directives))
 213         (push form results)
 214         (setf remaining-directives new-directives)))
 215     (reverse results)))
 216
 217 (defun expand-directive (directive more-directives)
 218   (etypecase directive
 219     (format-directive
 220      (let ((expander
 221             (aref *format-directive-expanders*
 222                   (char-code (format-directive-character directive))))
 223            (*default-format-error-offset*
 224             (1- (format-directive-end directive))))
 225        (declare (type (or null function) expander))
 226        (if expander
 227            (funcall expander directive more-directives)
 228            (error 'format-error
 229                   :complaint "unknown directive ~@[(character: ~A)~]"
 230                   :args (list (char-name (format-directive-character directive)))))))
 231     (simple-string
 232      (values `(write-string ,directive stream)
 233              more-directives))))
 234
 235 (defmacro-mundanely expander-next-arg (string offset)
 236   `(if args
 237        (pop args)
 238        (error 'format-error
 239               :complaint "no more arguments"
 240               :control-string ,string
 241               :offset ,offset)))
 242
 243 (defun expand-next-arg (&optional offset)
 244   (if (or *orig-args-available* (not *only-simple-args*))
 245       `(,*expander-next-arg-macro*
 246         ,*default-format-error-control-string*
 247         ,(or offset *default-format-error-offset*))
 248       (let ((symbol (gensym "FORMAT-ARG-")))
 249         (push (cons symbol (or offset *default-format-error-offset*))
 250               *simple-args*)
 251         symbol)))
 252
 253 (defmacro expand-bind-defaults (specs params &body body)
 254   (once-only ((params params))
 255     (if specs
 256         (collect ((expander-bindings) (runtime-bindings))
 257                  (dolist (spec specs)
 258                    (destructuring-bind (var default) spec
 259                      (let ((symbol (gensym)))
 260                        (expander-bindings
 261                         `(,var ',symbol))
 262                        (runtime-bindings
 263                         `(list ',symbol
 264                                (let* ((param-and-offset (pop ,params))
 265                                       (offset (car param-and-offset))
 266                                       (param (cdr param-and-offset)))
 267                                  (case param
 268                                    (:arg `(or ,(expand-next-arg offset)
 269                                               ,,default))
 270                                    (:remaining
 271                                     (setf *only-simple-args* nil)
 272                                     '(length args))
 273                                    ((nil) ,default)
 274                                    (t param))))))))
 275                  `(let ,(expander-bindings)
 276                     `(let ,(list ,@(runtime-bindings))
 277                        ,@(if ,params
 278                              (error
 279                               'format-error
 280                               :complaint
 281                               "too many parameters, expected no more than ~W"
 282                               :args (list ,(length specs))
 283                               :offset (caar ,params)))
 284                        ,,@body)))
 285         `(progn
 286            (when ,params
 287              (error 'format-error
 288                     :complaint "too many parameters, expected none"
 289                     :offset (caar ,params)))
 290            ,@body))))
 291 \f
 292 ;;;; format directive machinery
 293
 294 ;;; FIXME: only used in this file, could be SB!XC:DEFMACRO in EVAL-WHEN
 295 (defmacro def-complex-format-directive (char lambda-list &body body)
 296   (let ((defun-name (intern (format nil
 297                                     "~:@(~:C~)-FORMAT-DIRECTIVE-EXPANDER"
 298                                     char)))
 299         (directive (gensym))
 300         (directives (if lambda-list (car (last lambda-list)) (gensym))))
 301     `(progn
 302        (defun ,defun-name (,directive ,directives)
 303          ,@(if lambda-list
 304                `((let ,(mapcar (lambda (var)
 305                                  `(,var
 306                                    (,(symbolicate "FORMAT-DIRECTIVE-" var)
 307                                     ,directive)))
 308                                (butlast lambda-list))
 309                    ,@body))
 310                `((declare (ignore ,directive ,directives))
 311                  ,@body)))
 312        (%set-format-directive-expander ,char #',defun-name))))
 313
 314 ;;; FIXME: only used in this file, could be SB!XC:DEFMACRO in EVAL-WHEN
 315 (defmacro def-format-directive (char lambda-list &body body)
 316   (let ((directives (gensym))
 317         (declarations nil)
 318         (body-without-decls body))
 319     (loop
 320       (let ((form (car body-without-decls)))
 321         (unless (and (consp form) (eq (car form) 'declare))
 322           (return))
 323         (push (pop body-without-decls) declarations)))
 324     (setf declarations (reverse declarations))
 325     `(def-complex-format-directive ,char (,@lambda-list ,directives)
 326        ,@declarations
 327        (values (progn ,@body-without-decls)
 328                ,directives))))
 329
 330 (eval-when (#-sb-xc :compile-toplevel :load-toplevel :execute)
 331
 332 (defun %set-format-directive-expander (char fn)
 333   (setf (aref *format-directive-expanders* (char-code (char-upcase char))) fn)
 334   char)
 335
 336 (defun %set-format-directive-interpreter (char fn)
 337   (setf (aref *format-directive-interpreters*
 338               (char-code (char-upcase char)))
 339         fn)
 340   char)
 341
 342 (defun find-directive (directives kind stop-at-semi)
 343   (if directives
 344       (let ((next (car directives)))
 345         (if (format-directive-p next)
 346             (let ((char (format-directive-character next)))
 347               (if (or (char= kind char)
 348                       (and stop-at-semi (char= char #\;)))
 349                   (car directives)
 350                   (find-directive
 351                    (cdr (flet ((after (char)
 352                                  (member (find-directive (cdr directives)
 353                                                          char
 354                                                          nil)
 355                                          directives)))
 356                           (case char
 357                             (#\( (after #\)))
 358                             (#\< (after #\>))
 359                             (#\[ (after #\]))
 360                             (#\{ (after #\}))
 361                             (t directives))))
 362                    kind stop-at-semi)))
 363             (find-directive (cdr directives) kind stop-at-semi)))))
 364
 365 ) ; EVAL-WHEN
 366 \f
 367 ;;;; format directives for simple output
 368
 369 (def-format-directive #\A (colonp atsignp params)
 370   (if params
 371       (expand-bind-defaults ((mincol 0) (colinc 1) (minpad 0)
 372                              (padchar #\space))
 373                      params
 374         `(format-princ stream ,(expand-next-arg) ',colonp ',atsignp
 375                        ,mincol ,colinc ,minpad ,padchar))
 376       `(princ ,(if colonp
 377                    `(or ,(expand-next-arg) "()")
 378                    (expand-next-arg))
 379               stream)))
 380
 381 (def-format-directive #\S (colonp atsignp params)
 382   (cond (params
 383          (expand-bind-defaults ((mincol 0) (colinc 1) (minpad 0)
 384                                 (padchar #\space))
 385                         params
 386            `(format-prin1 stream ,(expand-next-arg) ,colonp ,atsignp
 387                           ,mincol ,colinc ,minpad ,padchar)))
 388         (colonp
 389          `(let ((arg ,(expand-next-arg)))
 390             (if arg
 391                 (prin1 arg stream)
 392                 (princ "()" stream))))
 393         (t
 394          `(prin1 ,(expand-next-arg) stream))))
 395
 396 (def-format-directive #\C (colonp atsignp params)
 397   (expand-bind-defaults () params
 398     (if colonp
 399         `(format-print-named-character ,(expand-next-arg) stream)
 400         (if atsignp
 401             `(prin1 ,(expand-next-arg) stream)
 402             `(write-char ,(expand-next-arg) stream)))))
 403
 404 (def-format-directive #\W (colonp atsignp params)
 405   (expand-bind-defaults () params
 406     (if (or colonp atsignp)
 407         `(let (,@(when colonp
 408                    '((*print-pretty* t)))
 409                ,@(when atsignp
 410                    '((*print-level* nil)
 411                      (*print-length* nil))))
 412            (output-object ,(expand-next-arg) stream))
 413         `(output-object ,(expand-next-arg) stream))))
 414 \f
 415 ;;;; format directives for integer output
 416
 417 (defun expand-format-integer (base colonp atsignp params)
 418   (if (or colonp atsignp params)
 419       (expand-bind-defaults
 420           ((mincol 0) (padchar #\space) (commachar #\,) (commainterval 3))
 421           params
 422         `(format-print-integer stream ,(expand-next-arg) ,colonp ,atsignp
 423                                ,base ,mincol ,padchar ,commachar
 424                                ,commainterval))
 425       `(write ,(expand-next-arg) :stream stream :base ,base :radix nil
 426               :escape nil)))
 427
 428 (def-format-directive #\D (colonp atsignp params)
 429   (expand-format-integer 10 colonp atsignp params))
 430
 431 (def-format-directive #\B (colonp atsignp params)
 432   (expand-format-integer 2 colonp atsignp params))
 433
 434 (def-format-directive #\O (colonp atsignp params)
 435   (expand-format-integer 8 colonp atsignp params))
 436
 437 (def-format-directive #\X (colonp atsignp params)
 438   (expand-format-integer 16 colonp atsignp params))
 439
 440 (def-format-directive #\R (colonp atsignp params)
 441   (if params
 442       (expand-bind-defaults
 443           ((base 10) (mincol 0) (padchar #\space) (commachar #\,)
 444            (commainterval 3))
 445           params
 446         `(format-print-integer stream ,(expand-next-arg) ,colonp ,atsignp
 447                                ,base ,mincol
 448                                ,padchar ,commachar ,commainterval))
 449       (if atsignp
 450           (if colonp
 451               `(format-print-old-roman stream ,(expand-next-arg))
 452               `(format-print-roman stream ,(expand-next-arg)))
 453           (if colonp
 454               `(format-print-ordinal stream ,(expand-next-arg))
 455               `(format-print-cardinal stream ,(expand-next-arg))))))
 456 \f
 457 ;;;; format directive for pluralization
 458
 459 (def-format-directive #\P (colonp atsignp params end)
 460   (expand-bind-defaults () params
 461     (let ((arg (cond
 462                 ((not colonp)
 463                  (expand-next-arg))
 464                 (*orig-args-available*
 465                  `(if (eq orig-args args)
 466                       (error 'format-error
 467                              :complaint "no previous argument"
 468                              :offset ,(1- end))
 469                       (do ((arg-ptr orig-args (cdr arg-ptr)))
 470                           ((eq (cdr arg-ptr) args)
 471                            (car arg-ptr)))))
 472                 (*only-simple-args*
 473                  (unless *simple-args*
 474                    (error 'format-error
 475                           :complaint "no previous argument"))
 476                  (caar *simple-args*))
 477                 (t
 478                  (/show0 "THROWing NEED-ORIG-ARGS from tilde-P")
 479                  (throw 'need-orig-args nil)))))
 480       (if atsignp
 481           `(write-string (if (eql ,arg 1) "y" "ies") stream)
 482           `(unless (eql ,arg 1) (write-char #\s stream))))))
 483 \f
 484 ;;;; format directives for floating point output
 485
 486 (def-format-directive #\F (colonp atsignp params)
 487   (when colonp
 488     (error 'format-error
 489            :complaint
 490            "The colon modifier cannot be used with this directive."))
 491   (expand-bind-defaults ((w nil) (d nil) (k nil) (ovf nil) (pad #\space)) params
 492     `(format-fixed stream ,(expand-next-arg) ,w ,d ,k ,ovf ,pad ,atsignp)))
 493
 494 (def-format-directive #\E (colonp atsignp params)
 495   (when colonp
 496     (error 'format-error
 497            :complaint
 498            "The colon modifier cannot be used with this directive."))
 499   (expand-bind-defaults
 500       ((w nil) (d nil) (e nil) (k 1) (ovf nil) (pad #\space) (mark nil))
 501       params
 502     `(format-exponential stream ,(expand-next-arg) ,w ,d ,e ,k ,ovf ,pad ,mark
 503                          ,atsignp)))
 504
 505 (def-format-directive #\G (colonp atsignp params)
 506   (when colonp
 507     (error 'format-error
 508            :complaint
 509            "The colon modifier cannot be used with this directive."))
 510   (expand-bind-defaults
 511       ((w nil) (d nil) (e nil) (k nil) (ovf nil) (pad #\space) (mark nil))
 512       params
 513     `(format-general stream ,(expand-next-arg) ,w ,d ,e ,k ,ovf ,pad ,mark ,atsignp)))
 514
 515 (def-format-directive #\$ (colonp atsignp params)
 516   (expand-bind-defaults ((d 2) (n 1) (w 0) (pad #\space)) params
 517     `(format-dollars stream ,(expand-next-arg) ,d ,n ,w ,pad ,colonp
 518                      ,atsignp)))
 519 \f
 520 ;;;; format directives for line/page breaks etc.
 521
 522 (def-format-directive #\% (colonp atsignp params)
 523   (when (or colonp atsignp)
 524     (error 'format-error
 525            :complaint
 526            "The colon and atsign modifiers cannot be used with this directive."
 527            ))
 528   (if params
 529       (expand-bind-defaults ((count 1)) params
 530         `(dotimes (i ,count)
 531            (terpri stream)))
 532       '(terpri stream)))
 533
 534 (def-format-directive #\& (colonp atsignp params)
 535   (when (or colonp atsignp)
 536     (error 'format-error
 537            :complaint
 538            "The colon and atsign modifiers cannot be used with this directive."
 539            ))
 540   (if params
 541       (expand-bind-defaults ((count 1)) params
 542         `(progn
 543            (fresh-line stream)
 544            (dotimes (i (1- ,count))
 545              (terpri stream))))
 546       '(fresh-line stream)))
 547
 548 (def-format-directive #\| (colonp atsignp params)
 549   (when (or colonp atsignp)
 550     (error 'format-error
 551            :complaint
 552            "The colon and atsign modifiers cannot be used with this directive."
 553            ))
 554   (if params
 555       (expand-bind-defaults ((count 1)) params
 556         `(dotimes (i ,count)
 557            (write-char (code-char form-feed-char-code) stream)))
 558       '(write-char (code-char form-feed-char-code) stream)))
 559
 560 (def-format-directive #\~ (colonp atsignp params)
 561   (when (or colonp atsignp)
 562     (error 'format-error
 563            :complaint
 564            "The colon and atsign modifiers cannot be used with this directive."
 565            ))
 566   (if params
 567       (expand-bind-defaults ((count 1)) params
 568         `(dotimes (i ,count)
 569            (write-char #\~ stream)))
 570       '(write-char #\~ stream)))
 571
 572 (def-complex-format-directive #\newline (colonp atsignp params directives)
 573   (when (and colonp atsignp)
 574     (error 'format-error
 575            :complaint "both colon and atsign modifiers used simultaneously"))
 576   (values (expand-bind-defaults () params
 577             (if atsignp
 578                 '(write-char #\newline stream)
 579                 nil))
 580           (if (and (not colonp)
 581                    directives
 582                    (simple-string-p (car directives)))
 583               (cons (string-left-trim *format-whitespace-chars*
 584                                       (car directives))
 585                     (cdr directives))
 586               directives)))
 587 \f
 588 ;;;; format directives for tabs and simple pretty printing
 589
 590 (def-format-directive #\T (colonp atsignp params)
 591   (if colonp
 592       (expand-bind-defaults ((n 1) (m 1)) params
 593         `(pprint-tab ,(if atsignp :section-relative :section)
 594                      ,n ,m stream))
 595       (if atsignp
 596           (expand-bind-defaults ((colrel 1) (colinc 1)) params
 597             `(format-relative-tab stream ,colrel ,colinc))
 598           (expand-bind-defaults ((colnum 1) (colinc 1)) params
 599             `(format-absolute-tab stream ,colnum ,colinc)))))
 600
 601 (def-format-directive #\_ (colonp atsignp params)
 602   (expand-bind-defaults () params
 603     `(pprint-newline ,(if colonp
 604                           (if atsignp
 605                               :mandatory
 606                               :fill)
 607                           (if atsignp
 608                               :miser
 609                               :linear))
 610                      stream)))
 611
 612 (def-format-directive #\I (colonp atsignp params)
 613   (when atsignp
 614     (error 'format-error
 615            :complaint
 616            "cannot use the at-sign modifier with this directive"))
 617   (expand-bind-defaults ((n 0)) params
 618     `(pprint-indent ,(if colonp :current :block) ,n stream)))
 619 \f
 620 ;;;; format directive for ~*
 621
 622 (def-format-directive #\* (colonp atsignp params end)
 623   (if atsignp
 624       (if colonp
 625           (error 'format-error
 626                  :complaint
 627                  "both colon and atsign modifiers used simultaneously")
 628           (expand-bind-defaults ((posn 0)) params
 629             (unless *orig-args-available*
 630               (/show0 "THROWing NEED-ORIG-ARGS from tilde-@*")
 631               (throw 'need-orig-args nil))
 632             `(if (<= 0 ,posn (length orig-args))
 633                  (setf args (nthcdr ,posn orig-args))
 634                  (error 'format-error
 635                         :complaint "Index ~W out of bounds. Should have been ~
 636                                     between 0 and ~W."
 637                         :args (list ,posn (length orig-args))
 638                         :offset ,(1- end)))))
 639       (if colonp
 640           (expand-bind-defaults ((n 1)) params
 641             (unless *orig-args-available*
 642               (/show0 "THROWing NEED-ORIG-ARGS from tilde-:*")
 643               (throw 'need-orig-args nil))
 644             `(do ((cur-posn 0 (1+ cur-posn))
 645                   (arg-ptr orig-args (cdr arg-ptr)))
 646                  ((eq arg-ptr args)
 647                   (let ((new-posn (- cur-posn ,n)))
 648                     (if (<= 0 new-posn (length orig-args))
 649                         (setf args (nthcdr new-posn orig-args))
 650                         (error 'format-error
 651                                :complaint
 652                                "Index ~W is out of bounds; should have been ~
 653                                 between 0 and ~W."
 654                                :args (list new-posn (length orig-args))
 655                                :offset ,(1- end)))))))
 656           (if params
 657               (expand-bind-defaults ((n 1)) params
 658                 (setf *only-simple-args* nil)
 659                 `(dotimes (i ,n)
 660                    ,(expand-next-arg)))
 661               (expand-next-arg)))))
 662 \f
 663 ;;;; format directive for indirection
 664
 665 (def-format-directive #\? (colonp atsignp params string end)
 666   (when colonp
 667     (error 'format-error
 668            :complaint "cannot use the colon modifier with this directive"))
 669   (expand-bind-defaults () params
 670     `(handler-bind
 671          ((format-error
 672            (lambda (condition)
 673              (error 'format-error
 674                     :complaint
 675                     "~A~%while processing indirect format string:"
 676                     :args (list condition)
 677                     :print-banner nil
 678                     :control-string ,string
 679                     :offset ,(1- end)))))
 680        ,(if atsignp
 681             (if *orig-args-available*
 682                 `(setf args (%format stream ,(expand-next-arg) orig-args args))
 683                 (throw 'need-orig-args nil))
 684             `(%format stream ,(expand-next-arg) ,(expand-next-arg))))))
 685 \f
 686 ;;;; format directives for capitalization
 687
 688 (def-complex-format-directive #\( (colonp atsignp params directives)
 689   (let ((close (find-directive directives #\) nil)))
 690     (unless close
 691       (error 'format-error
 692              :complaint "no corresponding close parenthesis"))
 693     (let* ((posn (position close directives))
 694            (before (subseq directives 0 posn))
 695            (after (nthcdr (1+ posn) directives)))
 696       (values
 697        (expand-bind-defaults () params
 698          `(let ((stream (make-case-frob-stream stream
 699                                                ,(if colonp
 700                                                     (if atsignp
 701                                                         :upcase
 702                                                         :capitalize)
 703                                                     (if atsignp
 704                                                         :capitalize-first
 705                                                         :downcase)))))
 706             ,@(expand-directive-list before)))
 707        after))))
 708
 709 (def-complex-format-directive #\) ()
 710   (error 'format-error
 711          :complaint "no corresponding open parenthesis"))
 712 \f
 713 ;;;; format directives and support functions for conditionalization
 714
 715 (def-complex-format-directive #\[ (colonp atsignp params directives)
 716   (multiple-value-bind (sublists last-semi-with-colon-p remaining)
 717       (parse-conditional-directive directives)
 718     (values
 719      (if atsignp
 720          (if colonp
 721              (error 'format-error
 722                     :complaint
 723                     "both colon and atsign modifiers used simultaneously")
 724              (if (cdr sublists)
 725                  (error 'format-error
 726                         :complaint
 727                         "Can only specify one section")
 728                  (expand-bind-defaults () params
 729                    (expand-maybe-conditional (car sublists)))))
 730          (if colonp
 731              (if (= (length sublists) 2)
 732                  (expand-bind-defaults () params
 733                    (expand-true-false-conditional (car sublists)
 734                                                   (cadr sublists)))
 735                  (error 'format-error
 736                         :complaint
 737                         "must specify exactly two sections"))
 738              (expand-bind-defaults ((index (expand-next-arg))) params
 739                (setf *only-simple-args* nil)
 740                (let ((clauses nil))
 741                  (when last-semi-with-colon-p
 742                    (push `(t ,@(expand-directive-list (pop sublists)))
 743                          clauses))
 744                  (let ((count (length sublists)))
 745                    (dolist (sublist sublists)
 746                      (push `(,(decf count)
 747                              ,@(expand-directive-list sublist))
 748                            clauses)))
 749                  `(case ,index ,@clauses)))))
 750      remaining)))
 751
 752 (defun parse-conditional-directive (directives)
 753   (let ((sublists nil)
 754         (last-semi-with-colon-p nil)
 755         (remaining directives))
 756     (loop
 757       (let ((close-or-semi (find-directive remaining #\] t)))
 758         (unless close-or-semi
 759           (error 'format-error
 760                  :complaint "no corresponding close bracket"))
 761         (let ((posn (position close-or-semi remaining)))
 762           (push (subseq remaining 0 posn) sublists)
 763           (setf remaining (nthcdr (1+ posn) remaining))
 764           (when (char= (format-directive-character close-or-semi) #\])
 765             (return))
 766           (setf last-semi-with-colon-p
 767                 (format-directive-colonp close-or-semi)))))
 768     (values sublists last-semi-with-colon-p remaining)))
 769
 770 (defun expand-maybe-conditional (sublist)
 771   (flet ((hairy ()
 772            `(let ((prev-args args)
 773                   (arg ,(expand-next-arg)))
 774               (when arg
 775                 (setf args prev-args)
 776                 ,@(expand-directive-list sublist)))))
 777     (if *only-simple-args*
 778         (multiple-value-bind (guts new-args)
 779             (let ((*simple-args* *simple-args*))
 780               (values (expand-directive-list sublist)
 781                       *simple-args*))
 782           (cond ((eq *simple-args* (cdr new-args))
 783                  (setf *simple-args* new-args)
 784                  `(when ,(caar new-args)
 785                     ,@guts))
 786                 (t
 787                  (setf *only-simple-args* nil)
 788                  (hairy))))
 789         (hairy))))
 790
 791 (defun expand-true-false-conditional (true false)
 792   (let ((arg (expand-next-arg)))
 793     (flet ((hairy ()
 794              `(if ,arg
 795                   (progn
 796                     ,@(expand-directive-list true))
 797                   (progn
 798                     ,@(expand-directive-list false)))))
 799       (if *only-simple-args*
 800           (multiple-value-bind (true-guts true-args true-simple)
 801               (let ((*simple-args* *simple-args*)
 802                     (*only-simple-args* t))
 803                 (values (expand-directive-list true)
 804                         *simple-args*
 805                         *only-simple-args*))
 806             (multiple-value-bind (false-guts false-args false-simple)
 807                 (let ((*simple-args* *simple-args*)
 808                       (*only-simple-args* t))
 809                   (values (expand-directive-list false)
 810                           *simple-args*
 811                           *only-simple-args*))
 812               (if (= (length true-args) (length false-args))
 813                   `(if ,arg
 814                        (progn
 815                          ,@true-guts)
 816                        ,(do ((false false-args (cdr false))
 817                              (true true-args (cdr true))
 818                              (bindings nil (cons `(,(caar false) ,(caar true))
 819                                                  bindings)))
 820                             ((eq true *simple-args*)
 821                              (setf *simple-args* true-args)
 822                              (setf *only-simple-args*
 823                                    (and true-simple false-simple))
 824                              (if bindings
 825                                  `(let ,bindings
 826                                     ,@false-guts)
 827                                  `(progn
 828                                     ,@false-guts)))))
 829                   (progn
 830                     (setf *only-simple-args* nil)
 831                     (hairy)))))
 832           (hairy)))))
 833
 834 (def-complex-format-directive #\; ()
 835   (error 'format-error
 836          :complaint
 837          "~~; directive not contained within either ~~[...~~] or ~~<...~~>"))
 838
 839 (def-complex-format-directive #\] ()
 840   (error 'format-error
 841          :complaint
 842          "no corresponding open bracket"))
 843 \f
 844 ;;;; format directive for up-and-out
 845
 846 (def-format-directive #\^ (colonp atsignp params)
 847   (when atsignp
 848     (error 'format-error
 849            :complaint "cannot use the at-sign modifier with this directive"))
 850   (when (and colonp (not *up-up-and-out-allowed*))
 851     (error 'format-error
 852            :complaint "attempt to use ~~:^ outside a ~~:{...~~} construct"))
 853   `(when ,(case (length params)
 854             (0 (if colonp
 855                    '(null outside-args)
 856                    (progn
 857                      (setf *only-simple-args* nil)
 858                      '(null args))))
 859             (1 (expand-bind-defaults ((count 0)) params
 860                  `(zerop ,count)))
 861             (2 (expand-bind-defaults ((arg1 0) (arg2 0)) params
 862                  `(= ,arg1 ,arg2)))
 863             (t (expand-bind-defaults ((arg1 0) (arg2 0) (arg3 0)) params
 864                  `(<= ,arg1 ,arg2 ,arg3))))
 865      ,(if colonp
 866           '(return-from outside-loop nil)
 867           '(return))))
 868 \f
 869 ;;;; format directives for iteration
 870
 871 (def-complex-format-directive #\{ (colonp atsignp params string end directives)
 872   (let ((close (find-directive directives #\} nil)))
 873     (unless close
 874       (error 'format-error
 875              :complaint "no corresponding close brace"))
 876     (let* ((closed-with-colon (format-directive-colonp close))
 877            (posn (position close directives)))
 878       (labels
 879           ((compute-insides ()
 880              (if (zerop posn)
 881                  (if *orig-args-available*
 882                      `((handler-bind
 883                            ((format-error
 884                              (lambda (condition)
 885                                (error 'format-error
 886                                       :complaint
 887                               "~A~%while processing indirect format string:"
 888                                       :args (list condition)
 889                                       :print-banner nil
 890                                       :control-string ,string
 891                                       :offset ,(1- end)))))
 892                          (setf args
 893                                (%format stream inside-string orig-args args))))
 894                      (throw 'need-orig-args nil))
 895                  (let ((*up-up-and-out-allowed* colonp))
 896                    (expand-directive-list (subseq directives 0 posn)))))
 897            (compute-loop-aux (count)
 898              (when atsignp
 899                (setf *only-simple-args* nil))
 900              `(loop
 901                 ,@(unless closed-with-colon
 902                     '((when (null args)
 903                         (return))))
 904                 ,@(when count
 905                     `((when (and ,count (minusp (decf ,count)))
 906                         (return))))
 907                 ,@(if colonp
 908                       (let ((*expander-next-arg-macro* 'expander-next-arg)
 909                             (*only-simple-args* nil)
 910                             (*orig-args-available* t))
 911                         `((let* ((orig-args ,(expand-next-arg))
 912                                  (outside-args args)
 913                                  (args orig-args))
 914                             (declare (ignorable orig-args outside-args args))
 915                             (block nil
 916                               ,@(compute-insides)))))
 917                       (compute-insides))
 918                 ,@(when closed-with-colon
 919                     '((when (null args)
 920                         (return))))))
 921            (compute-loop ()
 922              (if params
 923                  (expand-bind-defaults ((count nil)) params
 924                    (compute-loop-aux count))
 925                  (compute-loop-aux nil)))
 926            (compute-block ()
 927              (if colonp
 928                  `(block outside-loop
 929                     ,(compute-loop))
 930                  (compute-loop)))
 931            (compute-bindings ()
 932              (if atsignp
 933                  (compute-block)
 934                  `(let* ((orig-args ,(expand-next-arg))
 935                          (args orig-args))
 936                     (declare (ignorable orig-args args))
 937                     ,(let ((*expander-next-arg-macro* 'expander-next-arg)
 938                            (*only-simple-args* nil)
 939                            (*orig-args-available* t))
 940                        (compute-block))))))
 941         (values (if (zerop posn)
 942                     `(let ((inside-string ,(expand-next-arg)))
 943                        ,(compute-bindings))
 944                     (compute-bindings))
 945                 (nthcdr (1+ posn) directives))))))
 946
 947 (def-complex-format-directive #\} ()
 948   (error 'format-error
 949          :complaint "no corresponding open brace"))
 950 \f
 951 ;;;; format directives and support functions for justification
 952
 953 (defparameter *illegal-inside-justification*
 954   (mapcar (lambda (x) (parse-directive x 0))
 955           '("~W" "~:W" "~@W" "~:@W"
 956             "~_" "~:_" "~@_" "~:@_"
 957             "~:>" "~:@>"
 958             "~I" "~:I" "~@I" "~:@I"
 959             "~:T" "~:@T")))
 960
 961 (defun illegal-inside-justification-p (directive)
 962   (member directive *illegal-inside-justification*
 963           :test (lambda (x y)
 964                   (and (format-directive-p x)
 965                        (format-directive-p y)
 966                        (eql (format-directive-character x) (format-directive-character y))
 967                        (eql (format-directive-colonp x) (format-directive-colonp y))
 968                        (eql (format-directive-atsignp x) (format-directive-atsignp y))))))
 969
 970 (def-complex-format-directive #\< (colonp atsignp params string end directives)
 971   (multiple-value-bind (segments first-semi close remaining)
 972       (parse-format-justification directives)
 973     (values
 974      (if (format-directive-colonp close)
 975          (multiple-value-bind (prefix per-line-p insides suffix)
 976              (parse-format-logical-block segments colonp first-semi
 977                                          close params string end)
 978            (expand-format-logical-block prefix per-line-p insides
 979                                         suffix atsignp))
 980          (let ((count (reduce #'+ (mapcar (lambda (x) (count-if #'illegal-inside-justification-p x)) segments))))
 981            (when (> count 0)
 982              ;; ANSI specifies that "an error is signalled" in this
 983              ;; situation.
 984              (error 'format-error
 985                     :complaint "~D illegal directive~:P found inside justification block"
 986                     :args (list count)))
 987            (expand-format-justification segments colonp atsignp
 988                                       first-semi params)))
 989      remaining)))
 990
 991 (def-complex-format-directive #\> ()
 992   (error 'format-error
 993          :complaint "no corresponding open bracket"))
 994
 995 (defun parse-format-logical-block
 996        (segments colonp first-semi close params string end)
 997   (when params
 998     (error 'format-error
 999            :complaint "No parameters can be supplied with ~~<...~~:>."
1000            :offset (caar params)))
1001   (multiple-value-bind (prefix insides suffix)
1002       (multiple-value-bind (prefix-default suffix-default)
1003           (if colonp (values "(" ")") (values nil ""))
1004         (flet ((extract-string (list prefix-p)
1005                  (let ((directive (find-if #'format-directive-p list)))
1006                    (if directive
1007                        (error 'format-error
1008                               :complaint
1009                               "cannot include format directives inside the ~
1010                                ~:[suffix~;prefix~] segment of ~~<...~~:>"
1011                               :args (list prefix-p)
1012                               :offset (1- (format-directive-end directive)))
1013                        (apply #'concatenate 'string list)))))
1014         (case (length segments)
1015           (0 (values prefix-default nil suffix-default))
1016           (1 (values prefix-default (car segments) suffix-default))
1017           (2 (values (extract-string (car segments) t)
1018                      (cadr segments) suffix-default))
1019           (3 (values (extract-string (car segments) t)
1020                      (cadr segments)
1021                      (extract-string (caddr segments) nil)))
1022           (t
1023            (error 'format-error
1024                   :complaint "too many segments for ~~<...~~:>")))))
1025     (when (format-directive-atsignp close)
1026       (setf insides
1027             (add-fill-style-newlines insides
1028                                      string
1029                                      (if first-semi
1030                                          (format-directive-end first-semi)
1031                                          end))))
1032     (values prefix
1033             (and first-semi (format-directive-atsignp first-semi))
1034             insides
1035             suffix)))
1036
1037 (defun add-fill-style-newlines (list string offset)
1038   (if list
1039       (let ((directive (car list)))
1040         (if (simple-string-p directive)
1041             (nconc (add-fill-style-newlines-aux directive string offset)
1042                    (add-fill-style-newlines (cdr list)
1043                                             string
1044                                             (+ offset (length directive))))
1045             (cons directive
1046                   (add-fill-style-newlines (cdr list)
1047                                            string
1048                                            (format-directive-end directive)))))
1049       nil))
1050
1051 (defun add-fill-style-newlines-aux (literal string offset)
1052   (let ((end (length literal))
1053         (posn 0))
1054     (collect ((results))
1055       (loop
1056         (let ((blank (position #\space literal :start posn)))
1057           (when (null blank)
1058             (results (subseq literal posn))
1059             (return))
1060           (let ((non-blank (or (position #\space literal :start blank
1061                                          :test #'char/=)
1062                                end)))
1063             (results (subseq literal posn non-blank))
1064             (results (make-format-directive
1065                       :string string :character #\_
1066                       :start (+ offset non-blank) :end (+ offset non-blank)
1067                       :colonp t :atsignp nil :params nil))
1068             (setf posn non-blank))
1069           (when (= posn end)
1070             (return))))
1071       (results))))
1072
1073 (defun parse-format-justification (directives)
1074   (let ((first-semi nil)
1075         (close nil)
1076         (remaining directives))
1077     (collect ((segments))
1078       (loop
1079         (let ((close-or-semi (find-directive remaining #\> t)))
1080           (unless close-or-semi
1081             (error 'format-error
1082                    :complaint "no corresponding close bracket"))
1083           (let ((posn (position close-or-semi remaining)))
1084             (segments (subseq remaining 0 posn))
1085             (setf remaining (nthcdr (1+ posn) remaining)))
1086           (when (char= (format-directive-character close-or-semi)
1087                        #\>)
1088             (setf close close-or-semi)
1089             (return))
1090           (unless first-semi
1091             (setf first-semi close-or-semi))))
1092       (values (segments) first-semi close remaining))))
1093
1094 (sb!xc:defmacro expander-pprint-next-arg (string offset)
1095   `(progn
1096      (when (null args)
1097        (error 'format-error
1098               :complaint "no more arguments"
1099               :control-string ,string
1100               :offset ,offset))
1101      (pprint-pop)
1102      (pop args)))
1103
1104 (defun expand-format-logical-block (prefix per-line-p insides suffix atsignp)
1105   `(let ((arg ,(if atsignp 'args (expand-next-arg))))
1106      ,@(when atsignp
1107          (setf *only-simple-args* nil)
1108          '((setf args nil)))
1109      (pprint-logical-block
1110          (stream arg
1111                  ,(if per-line-p :per-line-prefix :prefix) ,prefix
1112                  :suffix ,suffix)
1113        (let ((args arg)
1114              ,@(unless atsignp
1115                  `((orig-args arg))))
1116          (declare (ignorable args ,@(unless atsignp '(orig-args))))
1117          (block nil
1118            ,@(let ((*expander-next-arg-macro* 'expander-pprint-next-arg)
1119                    (*only-simple-args* nil)
1120                    (*orig-args-available*
1121                     (if atsignp *orig-args-available* t)))
1122                (expand-directive-list insides)))))))
1123
1124 (defun expand-format-justification (segments colonp atsignp first-semi params)
1125   (let ((newline-segment-p
1126          (and first-semi
1127               (format-directive-colonp first-semi))))
1128     (expand-bind-defaults
1129         ((mincol 0) (colinc 1) (minpad 0) (padchar #\space))
1130         params
1131       `(let ((segments nil)
1132              ,@(when newline-segment-p
1133                  '((newline-segment nil)
1134                    (extra-space 0)
1135                    (line-len 72))))
1136          (block nil
1137            ,@(when newline-segment-p
1138                `((setf newline-segment
1139                        (with-output-to-string (stream)
1140                          ,@(expand-directive-list (pop segments))))
1141                  ,(expand-bind-defaults
1142                       ((extra 0)
1143                        (line-len '(or (sb!impl::line-length stream) 72)))
1144                       (format-directive-params first-semi)
1145                     `(setf extra-space ,extra line-len ,line-len))))
1146            ,@(mapcar (lambda (segment)
1147                        `(push (with-output-to-string (stream)
1148                                 ,@(expand-directive-list segment))
1149                               segments))
1150                      segments))
1151          (format-justification stream
1152                                ,@(if newline-segment-p
1153                                      '(newline-segment extra-space line-len)
1154                                      '(nil 0 0))
1155                                segments ,colonp ,atsignp
1156                                ,mincol ,colinc ,minpad ,padchar)))))
1157 \f
1158 ;;;; format directive and support function for user-defined method
1159
1160 (def-format-directive #\/ (string start end colonp atsignp params)
1161   (let ((symbol (extract-user-fun-name string start end)))
1162     (collect ((param-names) (bindings))
1163       (dolist (param-and-offset params)
1164         (let ((param (cdr param-and-offset)))
1165           (let ((param-name (gensym)))
1166             (param-names param-name)
1167             (bindings `(,param-name
1168                         ,(case param
1169                            (:arg (expand-next-arg))
1170                            (:remaining '(length args))
1171                            (t param)))))))
1172       `(let ,(bindings)
1173          (,symbol stream ,(expand-next-arg) ,colonp ,atsignp
1174                   ,@(param-names))))))
1175
1176 (defun extract-user-fun-name (string start end)
1177   (let ((slash (position #\/ string :start start :end (1- end)
1178                          :from-end t)))
1179     (unless slash
1180       (error 'format-error
1181              :complaint "malformed ~~/ directive"))
1182     (let* ((name (string-upcase (let ((foo string))
1183                                   ;; Hack alert: This is to keep the compiler
1184                                   ;; quiet about deleting code inside the
1185                                   ;; subseq expansion.
1186                                   (subseq foo (1+ slash) (1- end)))))
1187            (first-colon (position #\: name))
1188            (second-colon (if first-colon (position #\: name :start (1+ first-colon))))
1189            (package-name (if first-colon
1190                              (subseq name 0 first-colon)
1191                              "COMMON-LISP-USER"))
1192            (package (find-package package-name)))
1193       (unless package
1194         ;; FIXME: should be PACKAGE-ERROR? Could we just use
1195         ;; FIND-UNDELETED-PACKAGE-OR-LOSE?
1196         (error 'format-error
1197                :complaint "no package named ~S"
1198                :args (list package-name)))
1199       (intern (cond
1200                 ((and second-colon (= second-colon (1+ first-colon)))
1201                  (subseq name (1+ second-colon)))
1202                 (first-colon
1203                  (subseq name (1+ first-colon)))
1204                 (t name))
1205               package))))