1.0.41.42: ppc: Documentation and NEWS updates for threading.
[sbcl.git] / 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 reference-condition)
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    (second-relative :reader format-error-second-relative
21                     :initarg :second-relative :initform nil)
22    (print-banner :reader format-error-print-banner :initarg :print-banner
23                  :initform t))
24   (:report %print-format-error)
25   (:default-initargs :references nil))
26
27 (defun %print-format-error (condition stream)
28   (format stream
29           "~:[~*~;error in ~S: ~]~?~@[~%  ~A~%  ~V@T^~@[~V@T^~]~]"
30           (format-error-print-banner condition)
31           'format
32           (format-error-complaint condition)
33           (format-error-args condition)
34           (format-error-control-string condition)
35           (format-error-offset condition)
36           (format-error-second-relative condition)))
37 \f
38 (def!struct format-directive
39   (string (missing-arg) :type simple-string)
40   (start (missing-arg) :type (and unsigned-byte fixnum))
41   (end (missing-arg) :type (and unsigned-byte fixnum))
42   (character (missing-arg) :type character)
43   (colonp nil :type (member t nil))
44   (atsignp nil :type (member t nil))
45   (params nil :type list))
46 (def!method print-object ((x format-directive) stream)
47   (print-unreadable-object (x stream)
48     (write-string (format-directive-string x)
49                   stream
50                   :start (format-directive-start x)
51                   :end (format-directive-end x))))
52 \f
53 ;;;; TOKENIZE-CONTROL-STRING
54
55 (defun tokenize-control-string (string)
56   (declare (simple-string string))
57   (let ((index 0)
58         (end (length string))
59         (result nil)
60         ;; FIXME: consider rewriting this 22.3.5.2-related processing
61         ;; using specials to maintain state and doing the logic inside
62         ;; the directive expanders themselves.
63         (block)
64         (pprint)
65         (semicolon)
66         (justification-semicolon))
67     (loop
68       (let ((next-directive (or (position #\~ string :start index) end)))
69         (when (> next-directive index)
70           (push (subseq string index next-directive) result))
71         (when (= next-directive end)
72           (return))
73         (let* ((directive (parse-directive string next-directive))
74                (char (format-directive-character directive)))
75           ;; this processing is required by CLHS 22.3.5.2
76           (cond
77             ((char= char #\<) (push directive block))
78             ((and block (char= char #\;) (format-directive-colonp directive))
79              (setf semicolon directive))
80             ((char= char #\>)
81              (unless block
82                (error 'format-error
83                       :complaint "~~> without a matching ~~<"
84                       :control-string string
85                       :offset next-directive))
86              (cond
87                ((format-directive-colonp directive)
88                 (unless pprint
89                   (setf pprint (car block)))
90                 (setf semicolon nil))
91                (semicolon
92                 (unless justification-semicolon
93                   (setf justification-semicolon semicolon))))
94              (pop block))
95             ;; block cases are handled by the #\< expander/interpreter
96             ((not block)
97              (case char
98                ((#\W #\I #\_) (unless pprint (setf pprint directive)))
99                (#\T (when (and (format-directive-colonp directive)
100                                (not pprint))
101                       (setf pprint directive))))))
102           (push directive result)
103           (setf index (format-directive-end directive)))))
104     (when (and pprint justification-semicolon)
105       (let ((pprint-offset (1- (format-directive-end pprint)))
106             (justification-offset
107              (1- (format-directive-end justification-semicolon))))
108         (error 'format-error
109                :complaint "misuse of justification and pprint directives"
110                :control-string string
111                :offset (min pprint-offset justification-offset)
112                :second-relative (- (max pprint-offset justification-offset)
113                                    (min pprint-offset justification-offset)
114                                    1)
115                :references (list '(:ansi-cl :section (22 3 5 2))))))
116     (nreverse result)))
117
118 (defun parse-directive (string start)
119   (let ((posn (1+ start)) (params nil) (colonp nil) (atsignp nil)
120         (end (length string)))
121     (flet ((get-char ()
122              (if (= posn end)
123                  (error 'format-error
124                         :complaint "string ended before directive was found"
125                         :control-string string
126                         :offset start)
127                  (schar string posn)))
128            (check-ordering ()
129              (when (or colonp atsignp)
130                (error 'format-error
131                       :complaint "parameters found after #\\: or #\\@ modifier"
132                       :control-string string
133                       :offset posn
134                       :references (list '(:ansi-cl :section (22 3)))))))
135       (loop
136         (let ((char (get-char)))
137           (cond ((or (char<= #\0 char #\9) (char= char #\+) (char= char #\-))
138                  (check-ordering)
139                  (multiple-value-bind (param new-posn)
140                      (parse-integer string :start posn :junk-allowed t)
141                    (push (cons posn param) params)
142                    (setf posn new-posn)
143                    (case (get-char)
144                      (#\,)
145                      ((#\: #\@)
146                       (decf posn))
147                      (t
148                       (return)))))
149                 ((or (char= char #\v)
150                      (char= char #\V))
151                  (check-ordering)
152                  (push (cons posn :arg) params)
153                  (incf posn)
154                  (case (get-char)
155                    (#\,)
156                    ((#\: #\@)
157                     (decf posn))
158                    (t
159                     (return))))
160                 ((char= char #\#)
161                  (check-ordering)
162                  (push (cons posn :remaining) params)
163                  (incf posn)
164                  (case (get-char)
165                    (#\,)
166                    ((#\: #\@)
167                     (decf posn))
168                    (t
169                     (return))))
170                 ((char= char #\')
171                  (check-ordering)
172                  (incf posn)
173                  (push (cons posn (get-char)) params)
174                  (incf posn)
175                  (unless (char= (get-char) #\,)
176                    (decf posn)))
177                 ((char= char #\,)
178                  (check-ordering)
179                  (push (cons posn nil) params))
180                 ((char= char #\:)
181                  (if colonp
182                      (error 'format-error
183                             :complaint "too many colons supplied"
184                             :control-string string
185                             :offset posn
186                             :references (list '(:ansi-cl :section (22 3))))
187                      (setf colonp t)))
188                 ((char= char #\@)
189                  (if atsignp
190                      (error 'format-error
191                             :complaint "too many #\\@ characters supplied"
192                             :control-string string
193                             :offset posn
194                             :references (list '(:ansi-cl :section (22 3))))
195                      (setf atsignp t)))
196                 (t
197                  (when (and (char= (schar string (1- posn)) #\,)
198                             (or (< posn 2)
199                                 (char/= (schar string (- posn 2)) #\')))
200                    (check-ordering)
201                    (push (cons (1- posn) nil) params))
202                  (return))))
203         (incf posn))
204       (let ((char (get-char)))
205         (when (char= char #\/)
206           (let ((closing-slash (position #\/ string :start (1+ posn))))
207             (if closing-slash
208                 (setf posn closing-slash)
209                 (error 'format-error
210                        :complaint "no matching closing slash"
211                        :control-string string
212                        :offset posn))))
213         (make-format-directive
214          :string string :start start :end (1+ posn)
215          :character (char-upcase char)
216          :colonp colonp :atsignp atsignp
217          :params (nreverse params))))))
218 \f
219 ;;;; FORMATTER stuff
220
221 (sb!xc:defmacro formatter (control-string)
222   `#',(%formatter control-string))
223
224 (defun %formatter (control-string)
225   (block nil
226     (catch 'need-orig-args
227       (let* ((*simple-args* nil)
228              (*only-simple-args* t)
229              (guts (expand-control-string control-string))
230              (args nil))
231         (dolist (arg *simple-args*)
232           (push `(,(car arg)
233                   (error
234                    'format-error
235                    :complaint "required argument missing"
236                    :control-string ,control-string
237                    :offset ,(cdr arg)))
238                 args))
239         (return `(lambda (stream &optional ,@args &rest args)
240                    (declare (ignorable stream))
241                    ,guts
242                    args))))
243     (let ((*orig-args-available* t)
244           (*only-simple-args* nil))
245       `(lambda (stream &rest orig-args)
246          (declare (ignorable stream))
247          (let ((args orig-args))
248            ,(expand-control-string control-string)
249            args)))))
250
251 (defun expand-control-string (string)
252   (let* ((string (etypecase string
253                    (simple-string
254                     string)
255                    (string
256                     (coerce string 'simple-string))))
257          (*default-format-error-control-string* string)
258          (directives (tokenize-control-string string)))
259     `(block nil
260        ,@(expand-directive-list directives))))
261
262 (defun expand-directive-list (directives)
263   (let ((results nil)
264         (remaining-directives directives))
265     (loop
266       (unless remaining-directives
267         (return))
268       (multiple-value-bind (form new-directives)
269           (expand-directive (car remaining-directives)
270                             (cdr remaining-directives))
271         (push form results)
272         (setf remaining-directives new-directives)))
273     (reverse results)))
274
275 (defun expand-directive (directive more-directives)
276   (etypecase directive
277     (format-directive
278      (let ((expander
279             (let ((char (format-directive-character directive)))
280               (typecase char
281                 (base-char
282                  (aref *format-directive-expanders* (sb!xc:char-code char))))))
283            (*default-format-error-offset*
284             (1- (format-directive-end directive))))
285        (declare (type (or null function) expander))
286        (if expander
287            (funcall expander directive more-directives)
288            (error 'format-error
289                   :complaint "unknown directive ~@[(character: ~A)~]"
290                   :args (list (char-name (format-directive-character directive)))))))
291     (simple-string
292      (values `(write-string ,directive stream)
293              more-directives))))
294
295 (defmacro-mundanely expander-next-arg (string offset)
296   `(if args
297        (pop args)
298        (error 'format-error
299               :complaint "no more arguments"
300               :control-string ,string
301               :offset ,offset)))
302
303 (defun expand-next-arg (&optional offset)
304   (if (or *orig-args-available* (not *only-simple-args*))
305       `(,*expander-next-arg-macro*
306         ,*default-format-error-control-string*
307         ,(or offset *default-format-error-offset*))
308       (let ((symbol (sb!xc:gensym "FORMAT-ARG")))
309         (push (cons symbol (or offset *default-format-error-offset*))
310               *simple-args*)
311         symbol)))
312
313 (defmacro expand-bind-defaults (specs params &body body)
314   (once-only ((params params))
315     (if specs
316         (collect ((expander-bindings) (runtime-bindings))
317           (dolist (spec specs)
318             (destructuring-bind (var default) spec
319               (let ((symbol (sb!xc:gensym "FVAR")))
320                 (expander-bindings
321                  `(,var ',symbol))
322                 (runtime-bindings
323                  `(list ',symbol
324                    (let* ((param-and-offset (pop ,params))
325                           (offset (car param-and-offset))
326                           (param (cdr param-and-offset)))
327                      (case param
328                        (:arg `(or ,(expand-next-arg offset) ,,default))
329                        (:remaining
330                         (setf *only-simple-args* nil)
331                         '(length args))
332                        ((nil) ,default)
333                        (t param))))))))
334           `(let ,(expander-bindings)
335             `(let ,(list ,@(runtime-bindings))
336               ,@(if ,params
337                     (error
338                      'format-error
339                      :complaint "too many parameters, expected no more than ~W"
340                      :args (list ,(length specs))
341                      :offset (caar ,params)))
342               ,,@body)))
343         `(progn
344            (when ,params
345              (error 'format-error
346                     :complaint "too many parameters, expected none"
347                     :offset (caar ,params)))
348            ,@body))))
349 \f
350 ;;;; format directive machinery
351
352 (eval-when (:compile-toplevel :execute)
353 (#+sb-xc-host defmacro #-sb-xc-host sb!xc:defmacro def-complex-format-directive (char lambda-list &body body)
354   (let ((defun-name (intern (format nil
355                                     "~:@(~:C~)-FORMAT-DIRECTIVE-EXPANDER"
356                                     char)))
357         (directive (sb!xc:gensym "DIRECTIVE"))
358         (directives (if lambda-list (car (last lambda-list)) (sb!xc:gensym "DIRECTIVES"))))
359     `(progn
360        (defun ,defun-name (,directive ,directives)
361          ,@(if lambda-list
362                `((let ,(mapcar (lambda (var)
363                                  `(,var
364                                    (,(symbolicate "FORMAT-DIRECTIVE-" var)
365                                     ,directive)))
366                                (butlast lambda-list))
367                    ,@body))
368                `((declare (ignore ,directive ,directives))
369                  ,@body)))
370        (%set-format-directive-expander ,char #',defun-name))))
371
372 (#+sb-xc-host defmacro #-sb-xc-host sb!xc:defmacro def-format-directive (char lambda-list &body body)
373   (let ((directives (sb!xc:gensym "DIRECTIVES"))
374         (declarations nil)
375         (body-without-decls body))
376     (loop
377       (let ((form (car body-without-decls)))
378         (unless (and (consp form) (eq (car form) 'declare))
379           (return))
380         (push (pop body-without-decls) declarations)))
381     (setf declarations (reverse declarations))
382     `(def-complex-format-directive ,char (,@lambda-list ,directives)
383        ,@declarations
384        (values (progn ,@body-without-decls)
385                ,directives))))
386 ) ; EVAL-WHEN
387
388 (eval-when (#-sb-xc :compile-toplevel :load-toplevel :execute)
389
390 (defun %set-format-directive-expander (char fn)
391   (let ((code (sb!xc:char-code (char-upcase char))))
392     (setf (aref *format-directive-expanders* code) fn))
393   char)
394
395 (defun %set-format-directive-interpreter (char fn)
396   (let ((code (sb!xc:char-code (char-upcase char))))
397     (setf (aref *format-directive-interpreters* code) fn))
398   char)
399
400 (defun find-directive (directives kind stop-at-semi)
401   (if directives
402       (let ((next (car directives)))
403         (if (format-directive-p next)
404             (let ((char (format-directive-character next)))
405               (if (or (char= kind char)
406                       (and stop-at-semi (char= char #\;)))
407                   (car directives)
408                   (find-directive
409                    (cdr (flet ((after (char)
410                                  (member (find-directive (cdr directives)
411                                                          char
412                                                          nil)
413                                          directives)))
414                           (case char
415                             (#\( (after #\)))
416                             (#\< (after #\>))
417                             (#\[ (after #\]))
418                             (#\{ (after #\}))
419                             (t directives))))
420                    kind stop-at-semi)))
421             (find-directive (cdr directives) kind stop-at-semi)))))
422
423 ) ; EVAL-WHEN
424 \f
425 ;;;; format directives for simple output
426
427 (def-format-directive #\A (colonp atsignp params)
428   (if params
429       (expand-bind-defaults ((mincol 0) (colinc 1) (minpad 0)
430                              (padchar #\space))
431                      params
432         `(format-princ stream ,(expand-next-arg) ',colonp ',atsignp
433                        ,mincol ,colinc ,minpad ,padchar))
434       `(princ ,(if colonp
435                    `(or ,(expand-next-arg) "()")
436                    (expand-next-arg))
437               stream)))
438
439 (def-format-directive #\S (colonp atsignp params)
440   (cond (params
441          (expand-bind-defaults ((mincol 0) (colinc 1) (minpad 0)
442                                 (padchar #\space))
443                         params
444            `(format-prin1 stream ,(expand-next-arg) ,colonp ,atsignp
445                           ,mincol ,colinc ,minpad ,padchar)))
446         (colonp
447          `(let ((arg ,(expand-next-arg)))
448             (if arg
449                 (prin1 arg stream)
450                 (princ "()" stream))))
451         (t
452          `(prin1 ,(expand-next-arg) stream))))
453
454 (def-format-directive #\C (colonp atsignp params)
455   (expand-bind-defaults () params
456     (if colonp
457         `(format-print-named-character ,(expand-next-arg) stream)
458         (if atsignp
459             `(prin1 ,(expand-next-arg) stream)
460             `(write-char ,(expand-next-arg) stream)))))
461
462 (def-format-directive #\W (colonp atsignp params)
463   (expand-bind-defaults () params
464     (if (or colonp atsignp)
465         `(let (,@(when colonp
466                    '((*print-pretty* t)))
467                ,@(when atsignp
468                    '((*print-level* nil)
469                      (*print-length* nil))))
470            (output-object ,(expand-next-arg) stream))
471         `(output-object ,(expand-next-arg) stream))))
472 \f
473 ;;;; format directives for integer output
474
475 (defun expand-format-integer (base colonp atsignp params)
476   (if (or colonp atsignp params)
477       (expand-bind-defaults
478           ((mincol 0) (padchar #\space) (commachar #\,) (commainterval 3))
479           params
480         `(format-print-integer stream ,(expand-next-arg) ,colonp ,atsignp
481                                ,base ,mincol ,padchar ,commachar
482                                ,commainterval))
483       `(let ((*print-base* ,base)
484              (*print-radix* nil)
485              (*print-escape* nil))
486          (output-object ,(expand-next-arg) stream))))
487
488 (def-format-directive #\D (colonp atsignp params)
489   (expand-format-integer 10 colonp atsignp params))
490
491 (def-format-directive #\B (colonp atsignp params)
492   (expand-format-integer 2 colonp atsignp params))
493
494 (def-format-directive #\O (colonp atsignp params)
495   (expand-format-integer 8 colonp atsignp params))
496
497 (def-format-directive #\X (colonp atsignp params)
498   (expand-format-integer 16 colonp atsignp params))
499
500 (def-format-directive #\R (colonp atsignp params)
501   (expand-bind-defaults
502       ((base nil) (mincol 0) (padchar #\space) (commachar #\,)
503        (commainterval 3))
504       params
505     (let ((n-arg (sb!xc:gensym "ARG")))
506       `(let ((,n-arg ,(expand-next-arg)))
507          (if ,base
508              (format-print-integer stream ,n-arg ,colonp ,atsignp
509                                    ,base ,mincol
510                                    ,padchar ,commachar ,commainterval)
511              ,(if atsignp
512                   (if colonp
513                       `(format-print-old-roman stream ,n-arg)
514                       `(format-print-roman stream ,n-arg))
515                   (if colonp
516                       `(format-print-ordinal stream ,n-arg)
517                       `(format-print-cardinal stream ,n-arg))))))))
518 \f
519 ;;;; format directive for pluralization
520
521 (def-format-directive #\P (colonp atsignp params end)
522   (expand-bind-defaults () params
523     (let ((arg (cond
524                 ((not colonp)
525                  (expand-next-arg))
526                 (*orig-args-available*
527                  `(if (eq orig-args args)
528                       (error 'format-error
529                              :complaint "no previous argument"
530                              :offset ,(1- end))
531                       (do ((arg-ptr orig-args (cdr arg-ptr)))
532                           ((eq (cdr arg-ptr) args)
533                            (car arg-ptr)))))
534                 (*only-simple-args*
535                  (unless *simple-args*
536                    (error 'format-error
537                           :complaint "no previous argument"))
538                  (caar *simple-args*))
539                 (t
540                  (/show0 "THROWing NEED-ORIG-ARGS from tilde-P")
541                  (throw 'need-orig-args nil)))))
542       (if atsignp
543           `(write-string (if (eql ,arg 1) "y" "ies") stream)
544           `(unless (eql ,arg 1) (write-char #\s stream))))))
545 \f
546 ;;;; format directives for floating point output
547
548 (def-format-directive #\F (colonp atsignp params)
549   (when colonp
550     (error 'format-error
551            :complaint
552            "The colon modifier cannot be used with this directive."))
553   (expand-bind-defaults ((w nil) (d nil) (k nil) (ovf nil) (pad #\space)) params
554     `(format-fixed stream ,(expand-next-arg) ,w ,d ,k ,ovf ,pad ,atsignp)))
555
556 (def-format-directive #\E (colonp atsignp params)
557   (when colonp
558     (error 'format-error
559            :complaint
560            "The colon modifier cannot be used with this directive."))
561   (expand-bind-defaults
562       ((w nil) (d nil) (e nil) (k 1) (ovf nil) (pad #\space) (mark nil))
563       params
564     `(format-exponential stream ,(expand-next-arg) ,w ,d ,e ,k ,ovf ,pad ,mark
565                          ,atsignp)))
566
567 (def-format-directive #\G (colonp atsignp params)
568   (when colonp
569     (error 'format-error
570            :complaint
571            "The colon modifier cannot be used with this directive."))
572   (expand-bind-defaults
573       ((w nil) (d nil) (e nil) (k nil) (ovf nil) (pad #\space) (mark nil))
574       params
575     `(format-general stream ,(expand-next-arg) ,w ,d ,e ,k ,ovf ,pad ,mark ,atsignp)))
576
577 (def-format-directive #\$ (colonp atsignp params)
578   (expand-bind-defaults ((d 2) (n 1) (w 0) (pad #\space)) params
579     `(format-dollars stream ,(expand-next-arg) ,d ,n ,w ,pad ,colonp
580                      ,atsignp)))
581 \f
582 ;;;; format directives for line/page breaks etc.
583
584 (def-format-directive #\% (colonp atsignp params)
585   (when (or colonp atsignp)
586     (error 'format-error
587            :complaint
588            "The colon and atsign modifiers cannot be used with this directive."
589            ))
590   (if params
591       (expand-bind-defaults ((count 1)) params
592         `(dotimes (i ,count)
593            (terpri stream)))
594       '(terpri stream)))
595
596 (def-format-directive #\& (colonp atsignp params)
597   (when (or colonp atsignp)
598     (error 'format-error
599            :complaint
600            "The colon and atsign modifiers cannot be used with this directive."
601            ))
602   (if params
603       (expand-bind-defaults ((count 1)) params
604         `(progn
605            (fresh-line stream)
606            (dotimes (i (1- ,count))
607              (terpri stream))))
608       '(fresh-line stream)))
609
610 (def-format-directive #\| (colonp atsignp params)
611   (when (or colonp atsignp)
612     (error 'format-error
613            :complaint
614            "The colon and atsign modifiers cannot be used with this directive."
615            ))
616   (if params
617       (expand-bind-defaults ((count 1)) params
618         `(dotimes (i ,count)
619            (write-char (code-char form-feed-char-code) stream)))
620       '(write-char (code-char form-feed-char-code) stream)))
621
622 (def-format-directive #\~ (colonp atsignp params)
623   (when (or colonp atsignp)
624     (error 'format-error
625            :complaint
626            "The colon and atsign modifiers cannot be used with this directive."
627            ))
628   (if params
629       (expand-bind-defaults ((count 1)) params
630         `(dotimes (i ,count)
631            (write-char #\~ stream)))
632       '(write-char #\~ stream)))
633
634 (def-complex-format-directive #\newline (colonp atsignp params directives)
635   (when (and colonp atsignp)
636     (error 'format-error
637            :complaint "both colon and atsign modifiers used simultaneously"))
638   (values (expand-bind-defaults () params
639             (if atsignp
640                 '(write-char #\newline stream)
641                 nil))
642           (if (and (not colonp)
643                    directives
644                    (simple-string-p (car directives)))
645               (cons (string-left-trim *format-whitespace-chars*
646                                       (car directives))
647                     (cdr directives))
648               directives)))
649 \f
650 ;;;; format directives for tabs and simple pretty printing
651
652 (def-format-directive #\T (colonp atsignp params)
653   (if colonp
654       (expand-bind-defaults ((n 1) (m 1)) params
655         `(pprint-tab ,(if atsignp :section-relative :section)
656                      ,n ,m stream))
657       (if atsignp
658           (expand-bind-defaults ((colrel 1) (colinc 1)) params
659             `(format-relative-tab stream ,colrel ,colinc))
660           (expand-bind-defaults ((colnum 1) (colinc 1)) params
661             `(format-absolute-tab stream ,colnum ,colinc)))))
662
663 (def-format-directive #\_ (colonp atsignp params)
664   (expand-bind-defaults () params
665     `(pprint-newline ,(if colonp
666                           (if atsignp
667                               :mandatory
668                               :fill)
669                           (if atsignp
670                               :miser
671                               :linear))
672                      stream)))
673
674 (def-format-directive #\I (colonp atsignp params)
675   (when atsignp
676     (error 'format-error
677            :complaint
678            "cannot use the at-sign modifier with this directive"))
679   (expand-bind-defaults ((n 0)) params
680     `(pprint-indent ,(if colonp :current :block) ,n stream)))
681 \f
682 ;;;; format directive for ~*
683
684 (def-format-directive #\* (colonp atsignp params end)
685   (if atsignp
686       (if colonp
687           (error 'format-error
688                  :complaint
689                  "both colon and atsign modifiers used simultaneously")
690           (expand-bind-defaults ((posn 0)) params
691             (unless *orig-args-available*
692               (/show0 "THROWing NEED-ORIG-ARGS from tilde-@*")
693               (throw 'need-orig-args nil))
694             `(if (<= 0 ,posn (length orig-args))
695                  (setf args (nthcdr ,posn orig-args))
696                  (error 'format-error
697                         :complaint "Index ~W out of bounds. Should have been ~
698                                     between 0 and ~W."
699                         :args (list ,posn (length orig-args))
700                         :offset ,(1- end)))))
701       (if colonp
702           (expand-bind-defaults ((n 1)) params
703             (unless *orig-args-available*
704               (/show0 "THROWing NEED-ORIG-ARGS from tilde-:*")
705               (throw 'need-orig-args nil))
706             `(do ((cur-posn 0 (1+ cur-posn))
707                   (arg-ptr orig-args (cdr arg-ptr)))
708                  ((eq arg-ptr args)
709                   (let ((new-posn (- cur-posn ,n)))
710                     (if (<= 0 new-posn (length orig-args))
711                         (setf args (nthcdr new-posn orig-args))
712                         (error 'format-error
713                                :complaint
714                                "Index ~W is out of bounds; should have been ~
715                                 between 0 and ~W."
716                                :args (list new-posn (length orig-args))
717                                :offset ,(1- end)))))))
718           (if params
719               (expand-bind-defaults ((n 1)) params
720                 (setf *only-simple-args* nil)
721                 `(dotimes (i ,n)
722                    ,(expand-next-arg)))
723               (expand-next-arg)))))
724 \f
725 ;;;; format directive for indirection
726
727 (def-format-directive #\? (colonp atsignp params string end)
728   (when colonp
729     (error 'format-error
730            :complaint "cannot use the colon modifier with this directive"))
731   (expand-bind-defaults () params
732     `(handler-bind
733          ((format-error
734            (lambda (condition)
735              (error 'format-error
736                     :complaint
737                     "~A~%while processing indirect format string:"
738                     :args (list condition)
739                     :print-banner nil
740                     :control-string ,string
741                     :offset ,(1- end)))))
742        ,(if atsignp
743             (if *orig-args-available*
744                 `(setf args (%format stream ,(expand-next-arg) orig-args args))
745                 (throw 'need-orig-args nil))
746             `(%format stream ,(expand-next-arg) ,(expand-next-arg))))))
747 \f
748 ;;;; format directives for capitalization
749
750 (def-complex-format-directive #\( (colonp atsignp params directives)
751   (let ((close (find-directive directives #\) nil)))
752     (unless close
753       (error 'format-error
754              :complaint "no corresponding close parenthesis"))
755     (let* ((posn (position close directives))
756            (before (subseq directives 0 posn))
757            (after (nthcdr (1+ posn) directives)))
758       (values
759        (expand-bind-defaults () params
760          `(let ((stream (make-case-frob-stream stream
761                                                ,(if colonp
762                                                     (if atsignp
763                                                         :upcase
764                                                         :capitalize)
765                                                     (if atsignp
766                                                         :capitalize-first
767                                                         :downcase)))))
768             ,@(expand-directive-list before)))
769        after))))
770
771 (def-complex-format-directive #\) ()
772   (error 'format-error
773          :complaint "no corresponding open parenthesis"))
774 \f
775 ;;;; format directives and support functions for conditionalization
776
777 (def-complex-format-directive #\[ (colonp atsignp params directives)
778   (multiple-value-bind (sublists last-semi-with-colon-p remaining)
779       (parse-conditional-directive directives)
780     (values
781      (if atsignp
782          (if colonp
783              (error 'format-error
784                     :complaint
785                     "both colon and atsign modifiers used simultaneously")
786              (if (cdr sublists)
787                  (error 'format-error
788                         :complaint
789                         "Can only specify one section")
790                  (expand-bind-defaults () params
791                    (expand-maybe-conditional (car sublists)))))
792          (if colonp
793              (if (= (length sublists) 2)
794                  (expand-bind-defaults () params
795                    (expand-true-false-conditional (car sublists)
796                                                   (cadr sublists)))
797                  (error 'format-error
798                         :complaint
799                         "must specify exactly two sections"))
800              (expand-bind-defaults ((index nil)) params
801                (setf *only-simple-args* nil)
802                (let ((clauses nil)
803                      (case `(or ,index ,(expand-next-arg))))
804                  (when last-semi-with-colon-p
805                    (push `(t ,@(expand-directive-list (pop sublists)))
806                          clauses))
807                  (let ((count (length sublists)))
808                    (dolist (sublist sublists)
809                      (push `(,(decf count)
810                              ,@(expand-directive-list sublist))
811                            clauses)))
812                  `(case ,case ,@clauses)))))
813      remaining)))
814
815 (defun parse-conditional-directive (directives)
816   (let ((sublists nil)
817         (last-semi-with-colon-p nil)
818         (remaining directives))
819     (loop
820       (let ((close-or-semi (find-directive remaining #\] t)))
821         (unless close-or-semi
822           (error 'format-error
823                  :complaint "no corresponding close bracket"))
824         (let ((posn (position close-or-semi remaining)))
825           (push (subseq remaining 0 posn) sublists)
826           (setf remaining (nthcdr (1+ posn) remaining))
827           (when (char= (format-directive-character close-or-semi) #\])
828             (return))
829           (setf last-semi-with-colon-p
830                 (format-directive-colonp close-or-semi)))))
831     (values sublists last-semi-with-colon-p remaining)))
832
833 (defun expand-maybe-conditional (sublist)
834   (flet ((hairy ()
835            `(let ((prev-args args)
836                   (arg ,(expand-next-arg)))
837               (when arg
838                 (setf args prev-args)
839                 ,@(expand-directive-list sublist)))))
840     (if *only-simple-args*
841         (multiple-value-bind (guts new-args)
842             (let ((*simple-args* *simple-args*))
843               (values (expand-directive-list sublist)
844                       *simple-args*))
845           (cond ((and new-args (eq *simple-args* (cdr new-args)))
846                  (setf *simple-args* new-args)
847                  `(when ,(caar new-args)
848                     ,@guts))
849                 (t
850                  (setf *only-simple-args* nil)
851                  (hairy))))
852         (hairy))))
853
854 (defun expand-true-false-conditional (true false)
855   (let ((arg (expand-next-arg)))
856     (flet ((hairy ()
857              `(if ,arg
858                   (progn
859                     ,@(expand-directive-list true))
860                   (progn
861                     ,@(expand-directive-list false)))))
862       (if *only-simple-args*
863           (multiple-value-bind (true-guts true-args true-simple)
864               (let ((*simple-args* *simple-args*)
865                     (*only-simple-args* t))
866                 (values (expand-directive-list true)
867                         *simple-args*
868                         *only-simple-args*))
869             (multiple-value-bind (false-guts false-args false-simple)
870                 (let ((*simple-args* *simple-args*)
871                       (*only-simple-args* t))
872                   (values (expand-directive-list false)
873                           *simple-args*
874                           *only-simple-args*))
875               (if (= (length true-args) (length false-args))
876                   `(if ,arg
877                        (progn
878                          ,@true-guts)
879                        ,(do ((false false-args (cdr false))
880                              (true true-args (cdr true))
881                              (bindings nil (cons `(,(caar false) ,(caar true))
882                                                  bindings)))
883                             ((eq true *simple-args*)
884                              (setf *simple-args* true-args)
885                              (setf *only-simple-args*
886                                    (and true-simple false-simple))
887                              (if bindings
888                                  `(let ,bindings
889                                     ,@false-guts)
890                                  `(progn
891                                     ,@false-guts)))))
892                   (progn
893                     (setf *only-simple-args* nil)
894                     (hairy)))))
895           (hairy)))))
896
897 (def-complex-format-directive #\; ()
898   (error 'format-error
899          :complaint
900          "~~; directive not contained within either ~~[...~~] or ~~<...~~>"))
901
902 (def-complex-format-directive #\] ()
903   (error 'format-error
904          :complaint
905          "no corresponding open bracket"))
906 \f
907 ;;;; format directive for up-and-out
908
909 (def-format-directive #\^ (colonp atsignp params)
910   (when atsignp
911     (error 'format-error
912            :complaint "cannot use the at-sign modifier with this directive"))
913   (when (and colonp (not *up-up-and-out-allowed*))
914     (error 'format-error
915            :complaint "attempt to use ~~:^ outside a ~~:{...~~} construct"))
916   `(when ,(expand-bind-defaults ((arg1 nil) (arg2 nil) (arg3 nil)) params
917             `(cond (,arg3 (<= ,arg1 ,arg2 ,arg3))
918                    (,arg2 (eql ,arg1 ,arg2))
919                    (,arg1 (eql ,arg1 0))
920                    (t ,(if colonp
921                            '(null outside-args)
922                            (progn
923                              (setf *only-simple-args* nil)
924                              '(null args))))))
925      ,(if colonp
926           '(return-from outside-loop nil)
927           '(return))))
928 \f
929 ;;;; format directives for iteration
930
931 (def-complex-format-directive #\{ (colonp atsignp params string end directives)
932   (let ((close (find-directive directives #\} nil)))
933     (unless close
934       (error 'format-error
935              :complaint "no corresponding close brace"))
936     (let* ((closed-with-colon (format-directive-colonp close))
937            (posn (position close directives)))
938       (labels
939           ((compute-insides ()
940              (if (zerop posn)
941                  (if *orig-args-available*
942                      `((handler-bind
943                            ((format-error
944                              (lambda (condition)
945                                (error 'format-error
946                                       :complaint
947                               "~A~%while processing indirect format string:"
948                                       :args (list condition)
949                                       :print-banner nil
950                                       :control-string ,string
951                                       :offset ,(1- end)))))
952                          (setf args
953                                (%format stream inside-string orig-args args))))
954                      (throw 'need-orig-args nil))
955                  (let ((*up-up-and-out-allowed* colonp))
956                    (expand-directive-list (subseq directives 0 posn)))))
957            (compute-loop (count)
958              (when atsignp
959                (setf *only-simple-args* nil))
960              `(loop
961                 ,@(unless closed-with-colon
962                     '((when (null args)
963                         (return))))
964                 ,@(when count
965                     `((when (and ,count (minusp (decf ,count)))
966                         (return))))
967                 ,@(if colonp
968                       (let ((*expander-next-arg-macro* 'expander-next-arg)
969                             (*only-simple-args* nil)
970                             (*orig-args-available* t))
971                         `((let* ((orig-args ,(expand-next-arg))
972                                  (outside-args args)
973                                  (args orig-args))
974                             (declare (ignorable orig-args outside-args args))
975                             (block nil
976                               ,@(compute-insides)))))
977                       (compute-insides))
978                 ,@(when closed-with-colon
979                     '((when (null args)
980                         (return))))))
981            (compute-block (count)
982              (if colonp
983                  `(block outside-loop
984                     ,(compute-loop count))
985                  (compute-loop count)))
986            (compute-bindings (count)
987              (if atsignp
988                  (compute-block count)
989                  `(let* ((orig-args ,(expand-next-arg))
990                          (args orig-args))
991                    (declare (ignorable orig-args args))
992                    ,(let ((*expander-next-arg-macro* 'expander-next-arg)
993                           (*only-simple-args* nil)
994                           (*orig-args-available* t))
995                       (compute-block count))))))
996         (values (if params
997                     (expand-bind-defaults ((count nil)) params
998                       (if (zerop posn)
999                           `(let ((inside-string ,(expand-next-arg)))
1000                             ,(compute-bindings count))
1001                           (compute-bindings count)))
1002                     (if (zerop posn)
1003                         `(let ((inside-string ,(expand-next-arg)))
1004                           ,(compute-bindings nil))
1005                         (compute-bindings nil)))
1006                 (nthcdr (1+ posn) directives))))))
1007
1008 (def-complex-format-directive #\} ()
1009   (error 'format-error
1010          :complaint "no corresponding open brace"))
1011 \f
1012 ;;;; format directives and support functions for justification
1013
1014 (defparameter *illegal-inside-justification*
1015   (mapcar (lambda (x) (parse-directive x 0))
1016           '("~W" "~:W" "~@W" "~:@W"
1017             "~_" "~:_" "~@_" "~:@_"
1018             "~:>" "~:@>"
1019             "~I" "~:I" "~@I" "~:@I"
1020             "~:T" "~:@T")))
1021
1022 (defun illegal-inside-justification-p (directive)
1023   (member directive *illegal-inside-justification*
1024           :test (lambda (x y)
1025                   (and (format-directive-p x)
1026                        (format-directive-p y)
1027                        (eql (format-directive-character x) (format-directive-character y))
1028                        (eql (format-directive-colonp x) (format-directive-colonp y))
1029                        (eql (format-directive-atsignp x) (format-directive-atsignp y))))))
1030
1031 (def-complex-format-directive #\< (colonp atsignp params string end directives)
1032   (multiple-value-bind (segments first-semi close remaining)
1033       (parse-format-justification directives)
1034     (values
1035      (if (format-directive-colonp close)
1036          (multiple-value-bind (prefix per-line-p insides suffix)
1037              (parse-format-logical-block segments colonp first-semi
1038                                          close params string end)
1039            (expand-format-logical-block prefix per-line-p insides
1040                                         suffix atsignp))
1041          (let ((count (reduce #'+ (mapcar (lambda (x) (count-if #'illegal-inside-justification-p x)) segments))))
1042            (when (> count 0)
1043              ;; ANSI specifies that "an error is signalled" in this
1044              ;; situation.
1045              (error 'format-error
1046                     :complaint "~D illegal directive~:P found inside justification block"
1047                     :args (list count)
1048                     :references (list '(:ansi-cl :section (22 3 5 2)))))
1049            (expand-format-justification segments colonp atsignp
1050                                         first-semi params)))
1051      remaining)))
1052
1053 (def-complex-format-directive #\> ()
1054   (error 'format-error
1055          :complaint "no corresponding open bracket"))
1056
1057 (defun parse-format-logical-block
1058        (segments colonp first-semi close params string end)
1059   (when params
1060     (error 'format-error
1061            :complaint "No parameters can be supplied with ~~<...~~:>."
1062            :offset (caar params)))
1063   (multiple-value-bind (prefix insides suffix)
1064       (multiple-value-bind (prefix-default suffix-default)
1065           (if colonp (values "(" ")") (values "" ""))
1066         (flet ((extract-string (list prefix-p)
1067                  (let ((directive (find-if #'format-directive-p list)))
1068                    (if directive
1069                        (error 'format-error
1070                               :complaint
1071                               "cannot include format directives inside the ~
1072                                ~:[suffix~;prefix~] segment of ~~<...~~:>"
1073                               :args (list prefix-p)
1074                               :offset (1- (format-directive-end directive))
1075                               :references
1076                               (list '(:ansi-cl :section (22 3 5 2))))
1077                        (apply #'concatenate 'string list)))))
1078         (case (length segments)
1079           (0 (values prefix-default nil suffix-default))
1080           (1 (values prefix-default (car segments) suffix-default))
1081           (2 (values (extract-string (car segments) t)
1082                      (cadr segments) suffix-default))
1083           (3 (values (extract-string (car segments) t)
1084                      (cadr segments)
1085                      (extract-string (caddr segments) nil)))
1086           (t
1087            (error 'format-error
1088                   :complaint "too many segments for ~~<...~~:>")))))
1089     (when (format-directive-atsignp close)
1090       (setf insides
1091             (add-fill-style-newlines insides
1092                                      string
1093                                      (if first-semi
1094                                          (format-directive-end first-semi)
1095                                          end))))
1096     (values prefix
1097             (and first-semi (format-directive-atsignp first-semi))
1098             insides
1099             suffix)))
1100
1101 (defun add-fill-style-newlines (list string offset &optional last-directive)
1102   (cond
1103     (list
1104      (let ((directive (car list)))
1105        (cond
1106          ((simple-string-p directive)
1107           (let* ((non-space (position #\Space directive :test #'char/=))
1108                  (newlinep (and last-directive
1109                                 (char=
1110                                  (format-directive-character last-directive)
1111                                  #\Newline))))
1112             (cond
1113               ((and newlinep non-space)
1114                (nconc
1115                 (list (subseq directive 0 non-space))
1116                 (add-fill-style-newlines-aux
1117                  (subseq directive non-space) string (+ offset non-space))
1118                 (add-fill-style-newlines
1119                  (cdr list) string (+ offset (length directive)))))
1120               (newlinep
1121                (cons directive
1122                      (add-fill-style-newlines
1123                       (cdr list) string (+ offset (length directive)))))
1124               (t
1125                (nconc (add-fill-style-newlines-aux directive string offset)
1126                       (add-fill-style-newlines
1127                        (cdr list) string (+ offset (length directive))))))))
1128          (t
1129           (cons directive
1130                 (add-fill-style-newlines
1131                  (cdr list) string
1132                  (format-directive-end directive) directive))))))
1133     (t nil)))
1134
1135 (defun add-fill-style-newlines-aux (literal string offset)
1136   (let ((end (length literal))
1137         (posn 0))
1138     (collect ((results))
1139       (loop
1140         (let ((blank (position #\space literal :start posn)))
1141           (when (null blank)
1142             (results (subseq literal posn))
1143             (return))
1144           (let ((non-blank (or (position #\space literal :start blank
1145                                          :test #'char/=)
1146                                end)))
1147             (results (subseq literal posn non-blank))
1148             (results (make-format-directive
1149                       :string string :character #\_
1150                       :start (+ offset non-blank) :end (+ offset non-blank)
1151                       :colonp t :atsignp nil :params nil))
1152             (setf posn non-blank))
1153           (when (= posn end)
1154             (return))))
1155       (results))))
1156
1157 (defun parse-format-justification (directives)
1158   (let ((first-semi nil)
1159         (close nil)
1160         (remaining directives))
1161     (collect ((segments))
1162       (loop
1163         (let ((close-or-semi (find-directive remaining #\> t)))
1164           (unless close-or-semi
1165             (error 'format-error
1166                    :complaint "no corresponding close bracket"))
1167           (let ((posn (position close-or-semi remaining)))
1168             (segments (subseq remaining 0 posn))
1169             (setf remaining (nthcdr (1+ posn) remaining)))
1170           (when (char= (format-directive-character close-or-semi)
1171                        #\>)
1172             (setf close close-or-semi)
1173             (return))
1174           (unless first-semi
1175             (setf first-semi close-or-semi))))
1176       (values (segments) first-semi close remaining))))
1177
1178 (sb!xc:defmacro expander-pprint-next-arg (string offset)
1179   `(progn
1180      (when (null args)
1181        (error 'format-error
1182               :complaint "no more arguments"
1183               :control-string ,string
1184               :offset ,offset))
1185      (pprint-pop)
1186      (pop args)))
1187
1188 (defun expand-format-logical-block (prefix per-line-p insides suffix atsignp)
1189   `(let ((arg ,(if atsignp 'args (expand-next-arg))))
1190      ,@(when atsignp
1191          (setf *only-simple-args* nil)
1192          '((setf args nil)))
1193      (pprint-logical-block
1194          (stream arg
1195                  ,(if per-line-p :per-line-prefix :prefix) ,prefix
1196                  :suffix ,suffix)
1197        (let ((args arg)
1198              ,@(unless atsignp
1199                  `((orig-args arg))))
1200          (declare (ignorable args ,@(unless atsignp '(orig-args))))
1201          (block nil
1202            ,@(let ((*expander-next-arg-macro* 'expander-pprint-next-arg)
1203                    (*only-simple-args* nil)
1204                    (*orig-args-available*
1205                     (if atsignp *orig-args-available* t)))
1206                (expand-directive-list insides)))))))
1207
1208 (defun expand-format-justification (segments colonp atsignp first-semi params)
1209   (let ((newline-segment-p
1210          (and first-semi
1211               (format-directive-colonp first-semi))))
1212     (expand-bind-defaults
1213         ((mincol 0) (colinc 1) (minpad 0) (padchar #\space))
1214         params
1215       `(let ((segments nil)
1216              ,@(when newline-segment-p
1217                  '((newline-segment nil)
1218                    (extra-space 0)
1219                    (line-len 72))))
1220          (block nil
1221            ,@(when newline-segment-p
1222                `((setf newline-segment
1223                        (with-output-to-string (stream)
1224                          ,@(expand-directive-list (pop segments))))
1225                  ,(expand-bind-defaults
1226                       ((extra 0)
1227                        (line-len '(or (sb!impl::line-length stream) 72)))
1228                       (format-directive-params first-semi)
1229                     `(setf extra-space ,extra line-len ,line-len))))
1230            ,@(mapcar (lambda (segment)
1231                        `(push (with-output-to-string (stream)
1232                                 ,@(expand-directive-list segment))
1233                               segments))
1234                      segments))
1235          (format-justification stream
1236                                ,@(if newline-segment-p
1237                                      '(newline-segment extra-space line-len)
1238                                      '(nil 0 0))
1239                                segments ,colonp ,atsignp
1240                                ,mincol ,colinc ,minpad ,padchar)))))
1241 \f
1242 ;;;; format directive and support function for user-defined method
1243
1244 (def-format-directive #\/ (string start end colonp atsignp params)
1245   (let ((symbol (extract-user-fun-name string start end)))
1246     (collect ((param-names) (bindings))
1247       (dolist (param-and-offset params)
1248         (let ((param (cdr param-and-offset)))
1249           (let ((param-name (sb!xc:gensym "PARAM")))
1250             (param-names param-name)
1251             (bindings `(,param-name
1252                         ,(case param
1253                            (:arg (expand-next-arg))
1254                            (:remaining '(length args))
1255                            (t param)))))))
1256       `(let ,(bindings)
1257          (,symbol stream ,(expand-next-arg) ,colonp ,atsignp
1258                   ,@(param-names))))))
1259
1260 (defun extract-user-fun-name (string start end)
1261   (let ((slash (position #\/ string :start start :end (1- end)
1262                          :from-end t)))
1263     (unless slash
1264       (error 'format-error
1265              :complaint "malformed ~~/ directive"))
1266     (let* ((name (string-upcase (let ((foo string))
1267                                   ;; Hack alert: This is to keep the compiler
1268                                   ;; quiet about deleting code inside the
1269                                   ;; subseq expansion.
1270                                   (subseq foo (1+ slash) (1- end)))))
1271            (first-colon (position #\: name))
1272            (second-colon (if first-colon (position #\: name :start (1+ first-colon))))
1273            (package-name (if first-colon
1274                              (subseq name 0 first-colon)
1275                              "COMMON-LISP-USER"))
1276            (package (find-package package-name)))
1277       (unless package
1278         ;; FIXME: should be PACKAGE-ERROR? Could we just use
1279         ;; FIND-UNDELETED-PACKAGE-OR-LOSE?
1280         (error 'format-error
1281                :complaint "no package named ~S"
1282                :args (list package-name)))
1283       (intern (cond
1284                 ((and second-colon (= second-colon (1+ first-colon)))
1285                  (subseq name (1+ second-colon)))
1286                 (first-colon
1287                  (subseq name (1+ first-colon)))
1288                 (t name))
1289               package))))
1290
1291 ;;; compile-time checking for argument mismatch.  This code is
1292 ;;; inspired by that of Gerd Moellmann, and comes decorated with
1293 ;;; FIXMEs:
1294 (defun %compiler-walk-format-string (string args)
1295   (declare (type simple-string string))
1296   (let ((*default-format-error-control-string* string))
1297     (macrolet ((incf-both (&optional (increment 1))
1298                  `(progn
1299                    (incf min ,increment)
1300                    (incf max ,increment)))
1301                (walk-complex-directive (function)
1302                  `(multiple-value-bind (min-inc max-inc remaining)
1303                    (,function directive directives args)
1304                    (incf min min-inc)
1305                    (incf max max-inc)
1306                    (setq directives remaining))))
1307       ;; FIXME: these functions take a list of arguments as well as
1308       ;; the directive stream.  This is to enable possibly some
1309       ;; limited type checking on FORMAT's arguments, as well as
1310       ;; simple argument count mismatch checking: when the minimum and
1311       ;; maximum argument counts are the same at a given point, we
1312       ;; know which argument is going to be used for a given
1313       ;; directive, and some (annotated below) require arguments of
1314       ;; particular types.
1315       (labels
1316           ((walk-justification (justification directives args)
1317              (declare (ignore args))
1318              (let ((*default-format-error-offset*
1319                     (1- (format-directive-end justification))))
1320                (multiple-value-bind (segments first-semi close remaining)
1321                    (parse-format-justification directives)
1322                  (declare (ignore segments first-semi))
1323                  (cond
1324                    ((not (format-directive-colonp close))
1325                     (values 0 0 directives))
1326                    ((format-directive-atsignp justification)
1327                     (values 0 sb!xc:call-arguments-limit directives))
1328                    ;; FIXME: here we could assert that the
1329                    ;; corresponding argument was a list.
1330                    (t (values 1 1 remaining))))))
1331            (walk-conditional (conditional directives args)
1332              (let ((*default-format-error-offset*
1333                     (1- (format-directive-end conditional))))
1334                (multiple-value-bind (sublists last-semi-with-colon-p remaining)
1335                    (parse-conditional-directive directives)
1336                  (declare (ignore last-semi-with-colon-p))
1337                  (let ((sub-max
1338                         (loop for s in sublists
1339                               maximize (nth-value
1340                                         1 (walk-directive-list s args)))))
1341                    (cond
1342                      ((format-directive-atsignp conditional)
1343                       (values 1 (max 1 sub-max) remaining))
1344                      ((loop for p in (format-directive-params conditional)
1345                             thereis (or (integerp (cdr p))
1346                                         (memq (cdr p) '(:remaining :arg))))
1347                       (values 0 sub-max remaining))
1348                      ;; FIXME: if not COLONP, then the next argument
1349                      ;; must be a number.
1350                      (t (values 1 (1+ sub-max) remaining)))))))
1351            (walk-iteration (iteration directives args)
1352              (declare (ignore args))
1353              (let ((*default-format-error-offset*
1354                     (1- (format-directive-end iteration))))
1355                (let* ((close (find-directive directives #\} nil))
1356                       (posn (or (position close directives)
1357                                 (error 'format-error
1358                                        :complaint "no corresponding close brace")))
1359                       (remaining (nthcdr (1+ posn) directives)))
1360                  ;; FIXME: if POSN is zero, the next argument must be
1361                  ;; a format control (either a function or a string).
1362                  (if (format-directive-atsignp iteration)
1363                      (values (if (zerop posn) 1 0)
1364                              sb!xc:call-arguments-limit
1365                              remaining)
1366                      ;; FIXME: the argument corresponding to this
1367                      ;; directive must be a list.
1368                      (let ((nreq (if (zerop posn) 2 1)))
1369                        (values nreq nreq remaining))))))
1370            (walk-directive-list (directives args)
1371              (let ((min 0) (max 0))
1372                (loop
1373                 (let ((directive (pop directives)))
1374                   (when (null directive)
1375                     (return (values min (min max sb!xc:call-arguments-limit))))
1376                   (when (format-directive-p directive)
1377                     (incf-both (count :arg (format-directive-params directive)
1378                                       :key #'cdr))
1379                     (let ((c (format-directive-character directive)))
1380                       (cond
1381                         ((find c "ABCDEFGORSWX$/")
1382                          (incf-both))
1383                         ((char= c #\P)
1384                          (unless (format-directive-colonp directive)
1385                            (incf-both)))
1386                         ((or (find c "IT%&|_();>~") (char= c #\Newline)))
1387                         ;; FIXME: check correspondence of ~( and ~)
1388                         ((char= c #\<)
1389                          (walk-complex-directive walk-justification))
1390                         ((char= c #\[)
1391                          (walk-complex-directive walk-conditional))
1392                         ((char= c #\{)
1393                          (walk-complex-directive walk-iteration))
1394                         ((char= c #\?)
1395                          ;; FIXME: the argument corresponding to this
1396                          ;; directive must be a format control.
1397                          (cond
1398                            ((format-directive-atsignp directive)
1399                             (incf min)
1400                             (setq max sb!xc:call-arguments-limit))
1401                            (t (incf-both 2))))
1402                         (t (throw 'give-up-format-string-walk nil))))))))))
1403         (catch 'give-up-format-string-walk
1404           (let ((directives (tokenize-control-string string)))
1405             (walk-directive-list directives args)))))))