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1 | ;;; -*-lisp-*- |
2 | ;;; | |
3 | ;;; Various handy utilities | |
4 | ;;; | |
5 | ;;; (c) 2009 Straylight/Edgeware | |
6 | ;;; | |
7 | ||
8 | ;;;----- Licensing notice --------------------------------------------------- | |
9 | ;;; | |
e0808c47 | 10 | ;;; This file is part of the Sensible Object Design, an object system for C. |
dea4d055 MW |
11 | ;;; |
12 | ;;; SOD is free software; you can redistribute it and/or modify | |
13 | ;;; it under the terms of the GNU General Public License as published by | |
14 | ;;; the Free Software Foundation; either version 2 of the License, or | |
15 | ;;; (at your option) any later version. | |
16 | ;;; | |
17 | ;;; SOD is distributed in the hope that it will be useful, | |
18 | ;;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
20 | ;;; GNU General Public License for more details. | |
21 | ;;; | |
22 | ;;; You should have received a copy of the GNU General Public License | |
23 | ;;; along with SOD; if not, write to the Free Software Foundation, | |
24 | ;;; Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
25 | ||
26 | (cl:defpackage #:sod-utilities | |
27 | (:use #:common-lisp | |
28 | ||
29 | ;; MOP from somewhere. | |
30 | #+sbcl #:sb-mop | |
31 | #+(or cmu clisp) #:mop | |
32 | #+ecl #:clos)) | |
33 | ||
34 | (cl:in-package #:sod-utilities) | |
35 | ||
36 | ;;;-------------------------------------------------------------------------- | |
37 | ;;; Macro hacks. | |
38 | ||
39 | (export 'with-gensyms) | |
40 | (defmacro with-gensyms ((&rest binds) &body body) | |
41 | "Evaluate BODY with variables bound to fresh symbols. | |
42 | ||
43 | The BINDS are a list of entries (VAR [NAME]), and a singleton list can be | |
44 | replaced by just a symbol; each VAR is bound to a fresh symbol generated | |
45 | by (gensym NAME), where NAME defaults to the symbol-name of VAR." | |
46 | `(let (,@(mapcar (lambda (bind) | |
47 | (multiple-value-bind (var name) | |
48 | (if (atom bind) | |
49 | (values bind (concatenate 'string | |
50 | (symbol-name bind) "-")) | |
51 | (destructuring-bind | |
52 | (var &optional | |
53 | (name (concatenate 'string | |
54 | (symbol-name var) "-"))) | |
55 | bind | |
56 | (values var name))) | |
57 | `(,var (gensym ,name)))) | |
58 | binds)) | |
59 | ,@body)) | |
60 | ||
61 | (eval-when (:compile-toplevel :load-toplevel :execute) | |
62 | (defun strip-quote (form) | |
63 | "If FORM looks like (quote FOO) for self-evaluating FOO, return FOO. | |
64 | ||
65 | If FORM is a symbol whose constant value is `nil' then return `nil'. | |
66 | Otherwise return FORM unchanged. This makes it easier to inspect constant | |
67 | things. This is a utility for `once-only'." | |
68 | ||
69 | (cond ((and (consp form) | |
70 | (eq (car form) 'quote) | |
71 | (cdr form) | |
72 | (null (cddr form))) | |
73 | (let ((body (cadr form))) | |
74 | (if (or (not (or (consp body) (symbolp body))) | |
75 | (member body '(t nil)) | |
76 | (keywordp body)) | |
77 | body | |
78 | form))) | |
79 | ((and (symbolp form) (boundp form) (null (symbol-value form))) | |
80 | nil) | |
81 | (t | |
82 | form)))) | |
83 | ||
84 | (export 'once-only) | |
85 | (defmacro once-only (binds &body body) | |
86 | "Macro helper for preventing repeated evaluation. | |
87 | ||
88 | The syntax is actually hairier than shown: | |
89 | ||
90 | once-only ( [[ :environment ENV ]] { VAR | (VAR [VALUE-FORM]) }* ) | |
91 | { FORM }* | |
92 | ||
93 | So, the BINDS are a list of entries (VAR [VALUE-FORM]); a singleton list | |
94 | can be replaced by just a symbol VAR, and the VALUE-FORM defaults to VAR. | |
95 | But before them you can have keyword arguments. Only one is defined so | |
96 | far. See below for the crazy things that does. | |
97 | ||
98 | The result of evaluating a ONCE-ONLY form is a form with the structure | |
99 | ||
100 | (let ((#:GS1 VALUE-FORM1) | |
101 | ... | |
102 | (#:GSn VALUE-FORMn)) | |
103 | STUFF) | |
104 | ||
105 | where STUFF is the value of the BODY forms, as an implicit progn, in an | |
106 | environment with the VARs bound to the corresponding gensyms. | |
107 | ||
108 | As additional magic, if any of the VALUE-FORMs is actually constant (as | |
109 | determined by inspection, and aided by `constantp' if an :environment is | |
110 | supplied, then no gensym is constructed for it, and the VAR is bound | |
111 | directly to the constant form. Moreover, if the constant form looks like | |
112 | (quote FOO) for a self-evaluating FOO then the outer layer of quoting is | |
113 | stripped away." | |
114 | ||
115 | ;; We need an extra layer of gensyms in our expansion: we'll want the | |
116 | ;; expansion to examine the various VALUE-FORMs to find out whether they're | |
117 | ;; constant without evaluating them repeatedly. This also helps with | |
118 | ;; another problem: we explicitly encourage the rebinding of a VAR | |
119 | ;; (probably a macro argument) to a gensym which will be bound to the value | |
120 | ;; of the form previously held in VAR itself -- so the gensym and value | |
121 | ;; form must exist at the same time and we need two distinct variables. | |
122 | ||
123 | (with-gensyms ((envvar "ENV-") lets sym (bodyfunc "BODY-")) | |
124 | (let ((env nil)) | |
125 | ||
126 | ;; First things first: let's pick up the keywords. | |
127 | (loop | |
128 | (unless (and binds (keywordp (car binds))) | |
129 | (return)) | |
130 | (ecase (pop binds) | |
131 | (:environment (setf env (pop binds))))) | |
132 | ||
133 | ;; Now we'll investigate the bindings. Turn each one into a list (VAR | |
134 | ;; VALUE-FORM TEMP) where TEMP is an appropriate gensym -- see the note | |
135 | ;; above. | |
136 | (let ((canon (mapcar (lambda (bind) | |
137 | (multiple-value-bind (var form) | |
138 | (if (atom bind) | |
139 | (values bind bind) | |
140 | (destructuring-bind | |
141 | (var &optional (form var)) bind | |
142 | (values var form))) | |
143 | (list var form | |
144 | (gensym (format nil "T-~A-" | |
145 | (symbol-name var)))))) | |
146 | binds))) | |
147 | ||
148 | `(let* (,@(and env `((,envvar ,env))) | |
149 | (,lets nil) | |
150 | ,@(mapcar (lambda (bind) | |
151 | (destructuring-bind (var form temp) bind | |
152 | (declare (ignore var)) | |
153 | `(,temp ,form))) | |
154 | canon) | |
155 | ,@(mapcar (lambda (bind) | |
156 | (destructuring-bind (var form temp) bind | |
157 | (declare (ignore form)) | |
158 | `(,var | |
159 | (cond ((constantp ,temp | |
160 | ,@(and env `(,envvar))) | |
161 | (strip-quote ,temp)) | |
162 | ((symbolp ,temp) | |
163 | ,temp) | |
164 | (t | |
165 | (let ((,sym (gensym | |
166 | ,(concatenate 'string | |
167 | (symbol-name var) | |
168 | "-")))) | |
169 | (push (list ,sym ,temp) ,lets) | |
170 | ,sym)))))) | |
171 | canon)) | |
172 | (flet ((,bodyfunc () ,@body)) | |
173 | (if ,lets | |
174 | `(let (,@(nreverse ,lets)) ,(,bodyfunc)) | |
175 | (,bodyfunc)))))))) | |
176 | ||
177 | (export 'parse-body) | |
b8c698ee | 178 | (defun parse-body (body &key (docp t) (declp t)) |
dea4d055 MW |
179 | "Parse the BODY into a docstring, declarations and the body forms. |
180 | ||
181 | These are returned as three lists, so that they can be spliced into a | |
182 | macro expansion easily. The declarations are consolidated into a single | |
b8c698ee MW |
183 | `declare' form. If DOCP is nil then a docstring is not permitted; if |
184 | DECLP is nil, then declarations are not permitted." | |
dea4d055 MW |
185 | (let ((decls nil) |
186 | (doc nil)) | |
187 | (loop | |
188 | (cond ((null body) (return)) | |
b8c698ee | 189 | ((and declp (consp (car body)) (eq (caar body) 'declare)) |
dea4d055 | 190 | (setf decls (append decls (cdr (pop body))))) |
b8c698ee | 191 | ((and docp (stringp (car body)) (not doc) (cdr body)) |
dea4d055 MW |
192 | (setf doc (pop body))) |
193 | (t (return)))) | |
194 | (values (and doc (list doc)) | |
195 | (and decls (list (cons 'declare decls))) | |
196 | body))) | |
197 | ||
198 | ;;;-------------------------------------------------------------------------- | |
e8abb286 MW |
199 | ;;; Locatives. |
200 | ||
201 | (export '(loc locp)) | |
202 | (defstruct (loc (:predicate locp) (:constructor make-loc (reader writer))) | |
203 | "Locative data type. See `locf' and `ref'." | |
204 | (reader nil :type function) | |
205 | (writer nil :type function)) | |
206 | ||
207 | (export 'locf) | |
208 | (defmacro locf (place &environment env) | |
209 | "Slightly cheesy locatives. | |
210 | ||
211 | (locf PLACE) returns an object which, using the `ref' function, can be | |
212 | used to read or set the value of PLACE. It's cheesy because it uses | |
213 | closures rather than actually taking the address of something. Also, | |
214 | unlike Zetalisp, we don't overload `car' to do our dirty work." | |
215 | (multiple-value-bind | |
216 | (valtmps valforms newtmps setform getform) | |
217 | (get-setf-expansion place env) | |
218 | `(let* (,@(mapcar #'list valtmps valforms)) | |
219 | (make-loc (lambda () ,getform) | |
220 | (lambda (,@newtmps) ,setform))))) | |
221 | ||
222 | (export 'ref) | |
223 | (declaim (inline ref (setf ref))) | |
224 | (defun ref (loc) | |
225 | "Fetch the value referred to by a locative." | |
226 | (funcall (loc-reader loc))) | |
227 | (defun (setf ref) (new loc) | |
228 | "Store a new value in the place referred to by a locative." | |
229 | (funcall (loc-writer loc) new)) | |
230 | ||
231 | (export 'with-locatives) | |
232 | (defmacro with-locatives (locs &body body) | |
233 | "Evaluate BODY with implicit locatives. | |
234 | ||
235 | LOCS is a list of items of the form (SYM [LOC-EXPR]), where SYM is a | |
236 | symbol and LOC-EXPR evaluates to a locative. If LOC-EXPR is omitted, it | |
237 | defaults to SYM. As an abbreviation for a common case, LOCS may be a | |
238 | symbol instead of a list. | |
239 | ||
240 | The BODY is evaluated in an environment where each SYM is a symbol macro | |
241 | which expands to (ref LOC-EXPR) -- or, in fact, something similar which | |
242 | doesn't break if LOC-EXPR has side-effects. Thus, references, including | |
243 | `setf' forms, fetch or modify the thing referred to by the LOC-EXPR. | |
244 | Useful for covering over where something uses a locative." | |
245 | (setf locs (mapcar (lambda (item) | |
246 | (cond ((atom item) (list item item)) | |
247 | ((null (cdr item)) (list (car item) (car item))) | |
248 | (t item))) | |
249 | (if (listp locs) locs (list locs)))) | |
250 | (let ((tt (mapcar (lambda (l) (declare (ignore l)) (gensym)) locs)) | |
251 | (ll (mapcar #'cadr locs)) | |
252 | (ss (mapcar #'car locs))) | |
253 | `(let (,@(mapcar (lambda (tmp loc) `(,tmp ,loc)) tt ll)) | |
254 | (symbol-macrolet (,@(mapcar (lambda (sym tmp) | |
255 | `(,sym (ref ,tmp))) ss tt)) | |
256 | ,@body)))) | |
257 | ||
258 | ;;;-------------------------------------------------------------------------- | |
dea4d055 MW |
259 | ;;; Anaphorics. |
260 | ||
261 | (export 'it) | |
262 | ||
263 | (export 'aif) | |
264 | (defmacro aif (cond cons &optional (alt nil altp)) | |
265 | "If COND is not nil, evaluate CONS with `it' bound to the value of COND. | |
266 | ||
267 | Otherwise, if given, evaluate ALT; `it' isn't bound in ALT." | |
268 | (once-only (cond) | |
269 | `(if ,cond (let ((it ,cond)) ,cons) ,@(and altp `(,alt))))) | |
270 | ||
271 | (export 'awhen) | |
272 | (defmacro awhen (cond &body body) | |
273 | "If COND, evaluate BODY as a progn with `it' bound to the value of COND." | |
274 | `(let ((it ,cond)) (when it ,@body))) | |
275 | ||
276 | (export 'acond) | |
bf090e02 | 277 | (defmacro acond (&body clauses &environment env) |
dea4d055 MW |
278 | "Like COND, but with `it' bound to the value of the condition. |
279 | ||
280 | Each of the CLAUSES has the form (CONDITION FORM*); if a CONDITION is | |
281 | non-nil then evaluate the FORMs with `it' bound to the non-nil value, and | |
282 | return the value of the last FORM; if there are no FORMs, then return `it' | |
283 | itself. If the CONDITION is nil then continue with the next clause; if | |
284 | all clauses evaluate to nil then the result is nil." | |
285 | (labels ((walk (clauses) | |
286 | (if (null clauses) | |
287 | `nil | |
288 | (once-only (:environment env (cond (caar clauses))) | |
289 | (if (and (constantp cond) | |
290 | (if (and (consp cond) (eq (car cond) 'quote)) | |
291 | (cadr cond) cond)) | |
292 | (if (cdar clauses) | |
293 | `(let ((it ,cond)) | |
294 | (declare (ignorable it)) | |
295 | ,@(cdar clauses)) | |
296 | cond) | |
297 | `(if ,cond | |
298 | ,(if (cdar clauses) | |
299 | `(let ((it ,cond)) | |
300 | (declare (ignorable it)) | |
301 | ,@(cdar clauses)) | |
302 | cond) | |
303 | ,(walk (cdr clauses)))))))) | |
304 | (walk clauses))) | |
305 | ||
306 | (export '(acase aecase atypecase aetypecase)) | |
307 | (defmacro acase (value &body clauses) | |
308 | `(let ((it ,value)) (case it ,@clauses))) | |
309 | (defmacro aecase (value &body clauses) | |
310 | `(let ((it ,value)) (ecase it ,@clauses))) | |
311 | (defmacro atypecase (value &body clauses) | |
312 | `(let ((it ,value)) (typecase it ,@clauses))) | |
313 | (defmacro aetypecase (value &body clauses) | |
314 | `(let ((it ,value)) (etypecase it ,@clauses))) | |
315 | ||
316 | (export 'asetf) | |
317 | (defmacro asetf (&rest places-and-values &environment env) | |
318 | "Anaphoric update of places. | |
319 | ||
320 | The PLACES-AND-VALUES are alternating PLACEs and VALUEs. Each VALUE is | |
321 | evaluated with IT bound to the current value stored in the corresponding | |
322 | PLACE." | |
323 | `(progn ,@(loop for (place value) on places-and-values by #'cddr | |
324 | collect (multiple-value-bind | |
325 | (temps inits newtemps setform getform) | |
326 | (get-setf-expansion place env) | |
327 | `(let* (,@(mapcar #'list temps inits) | |
328 | (it ,getform)) | |
329 | (multiple-value-bind ,newtemps ,value | |
330 | ,setform)))))) | |
331 | ||
332 | ;;;-------------------------------------------------------------------------- | |
333 | ;;; MOP hacks (not terribly demanding). | |
334 | ||
bf090e02 MW |
335 | (export 'instance-initargs) |
336 | (defgeneric instance-initargs (instance) | |
337 | (:documentation | |
338 | "Return a plausble list of initargs for INSTANCE. | |
339 | ||
340 | The idea is that you can make a copy of INSTANCE by invoking | |
341 | ||
342 | (apply #'make-instance (class-of INSTANCE) | |
343 | (instance-initargs INSTANCE)) | |
344 | ||
345 | The default implementation works by inspecting the slot definitions and | |
346 | extracting suitable initargs, so this will only succeed if enough slots | |
347 | actually have initargs specified that `initialize-instance' can fill in | |
348 | the rest correctly. | |
349 | ||
350 | The list returned is freshly consed, and you can destroy it if you like.") | |
351 | (:method ((instance standard-object)) | |
352 | (mapcan (lambda (slot) | |
353 | (aif (slot-definition-initargs slot) | |
354 | (list (car it) | |
355 | (slot-value instance (slot-definition-name slot))) | |
356 | nil)) | |
357 | (class-slots (class-of instance))))) | |
358 | ||
dea4d055 MW |
359 | (export '(copy-instance copy-instance-using-class)) |
360 | (defgeneric copy-instance-using-class (class instance &rest initargs) | |
361 | (:documentation | |
362 | "Metaobject protocol hook for `copy-instance'.") | |
363 | (:method ((class standard-class) instance &rest initargs) | |
364 | (let ((copy (allocate-instance class))) | |
365 | (dolist (slot (class-slots class)) | |
366 | (let ((name (slot-definition-name slot))) | |
367 | (when (slot-boundp instance name) | |
368 | (setf (slot-value copy name) (slot-value instance name))))) | |
369 | (apply #'shared-initialize copy nil initargs)))) | |
370 | (defun copy-instance (object &rest initargs) | |
371 | "Construct and return a copy of OBJECT. | |
372 | ||
373 | The new object has the same class as OBJECT, and the same slot values | |
374 | except where overridden by INITARGS." | |
375 | (apply #'copy-instance-using-class (class-of object) object initargs)) | |
376 | ||
9ec578d9 MW |
377 | (export '(generic-function-methods method-specializers |
378 | eql-specializer eql-specializer-object)) | |
379 | ||
dea4d055 MW |
380 | ;;;-------------------------------------------------------------------------- |
381 | ;;; List utilities. | |
382 | ||
383 | (export 'make-list-builder) | |
384 | (defun make-list-builder (&optional initial) | |
385 | "Return a simple list builder." | |
386 | ||
387 | ;; The `builder' is just a cons cell whose cdr will be the list that's | |
388 | ;; wanted. Effectively, then, we have a list that's one item longer than | |
389 | ;; we actually want. The car of this extra initial cons cell is always the | |
390 | ;; last cons in the list -- which is now well defined because there's | |
391 | ;; always at least one. | |
392 | ||
393 | (let ((builder (cons nil initial))) | |
394 | (setf (car builder) (last builder)) | |
395 | builder)) | |
396 | ||
397 | (export 'lbuild-add) | |
398 | (defun lbuild-add (builder item) | |
399 | "Add an ITEM to the end of a list BUILDER." | |
400 | (let ((new (cons item nil))) | |
401 | (setf (cdar builder) new | |
402 | (car builder) new)) | |
403 | builder) | |
404 | ||
405 | (export 'lbuild-add-list) | |
406 | (defun lbuild-add-list (builder list) | |
407 | "Add a LIST to the end of a list BUILDER. The LIST will be clobbered." | |
408 | (when list | |
409 | (setf (cdar builder) list | |
410 | (car builder) (last list))) | |
411 | builder) | |
412 | ||
413 | (export 'lbuild-list) | |
414 | (defun lbuild-list (builder) | |
415 | "Return the constructed list." | |
416 | (cdr builder)) | |
417 | ||
418 | (export 'mappend) | |
419 | (defun mappend (function list &rest more-lists) | |
420 | "Like a nondestructive MAPCAN. | |
421 | ||
422 | Map FUNCTION over the the corresponding elements of LIST and MORE-LISTS, | |
423 | and return the result of appending all of the resulting lists." | |
424 | (reduce #'append (apply #'mapcar function list more-lists) :from-end t)) | |
425 | ||
426 | (export '(inconsistent-merge-error merge-error-candidates)) | |
427 | (define-condition inconsistent-merge-error (error) | |
428 | ((candidates :initarg :candidates | |
429 | :reader merge-error-candidates)) | |
430 | (:documentation | |
9fb4a980 | 431 | "Reports an inconsistency in the arguments passed to `merge-lists'.") |
dea4d055 MW |
432 | (:report (lambda (condition stream) |
433 | (format stream "Merge inconsistency: failed to decide among ~A." | |
434 | (merge-error-candidates condition))))) | |
435 | ||
436 | (export 'merge-lists) | |
437 | (defun merge-lists (lists &key pick (test #'eql)) | |
438 | "Return a merge of the given LISTS. | |
439 | ||
e8c5a09e | 440 | The resulting list contains the items of the given LISTS, with duplicates |
dea4d055 MW |
441 | removed. The order of the resulting list is consistent with the orders of |
442 | the input LISTS in the sense that if A precedes B in some input list then | |
443 | A will also precede B in the output list. If the lists aren't consistent | |
444 | (e.g., some list contains A followed by B, and another contains B followed | |
3109662a | 445 | by A) then an error of type `inconsistent-merge-error' is signalled. |
dea4d055 MW |
446 | |
447 | Item equality is determined by TEST. | |
448 | ||
449 | If there is an ambiguity at any point -- i.e., a choice between two or | |
450 | more possible next items to emit -- then PICK is called to arbitrate. | |
451 | PICK is called with two arguments: the list of candidate next items, and | |
e8c5a09e MW |
452 | the current output list. It should return one of the candidate items. |
453 | The order of the candidates in the list given to the PICK function | |
454 | reflects their order in the input LISTS: item A will precede item B in the | |
455 | candidates list if and only if an occurrence of A appears in an earlier | |
456 | input list than any occurrence of item B. (This completely determines the | |
457 | order of the candidates: it is not possible that two candidates appear in | |
458 | the same input list would resolve the ambiguity between them.) If PICK is | |
459 | omitted then the item chosen is the one appearing in the earliest of the | |
460 | input lists: i.e., effectively, the default PICK function is | |
461 | ||
462 | (lambda (candidates output-so-far) | |
463 | (declare (ignore output-so-far)) | |
464 | (car candidates)) | |
dea4d055 MW |
465 | |
466 | The primary use of this function is in computing class precedence lists. | |
467 | By building the input lists and selecting the PICK function appropriately, | |
468 | a variety of different CPL algorithms can be implemented." | |
469 | ||
022a3499 MW |
470 | (do ((lb (make-list-builder))) |
471 | ((null lists) (lbuild-list lb)) | |
dea4d055 MW |
472 | |
473 | ;; The candidate items are the ones at the front of the input lists. | |
474 | ;; Gather them up, removing duplicates. If a candidate is somewhere in | |
475 | ;; one of the other lists other than at the front then we reject it. If | |
476 | ;; we've just rejected everything, then we can make no more progress and | |
477 | ;; the input lists were inconsistent. | |
e8c5a09e MW |
478 | (let* ((candidates (delete-duplicates (mapcar #'car lists) |
479 | :test test :from-end t)) | |
dea4d055 MW |
480 | (leasts (remove-if (lambda (item) |
481 | (some (lambda (list) | |
482 | (member item (cdr list) :test test)) | |
483 | lists)) | |
484 | candidates)) | |
485 | (winner (cond ((null leasts) | |
486 | (error 'inconsistent-merge-error | |
487 | :candidates candidates)) | |
488 | ((null (cdr leasts)) | |
489 | (car leasts)) | |
490 | (pick | |
491 | (funcall pick leasts (lbuild-list lb))) | |
492 | (t (car leasts))))) | |
493 | ||
494 | ;; Check that the PICK function isn't conning us. | |
495 | (assert (member winner leasts :test test)) | |
496 | ||
497 | ;; Update the output list and remove the winning item from the input | |
498 | ;; lists. We know that it must be at the front of each input list | |
499 | ;; containing it. At this point, we discard input lists entirely when | |
500 | ;; they run out of entries. The loop ends when there are no more input | |
501 | ;; lists left, i.e., when we've munched all of the input items. | |
502 | (lbuild-add lb winner) | |
503 | (setf lists (delete nil (mapcar (lambda (list) | |
504 | (if (funcall test winner (car list)) | |
505 | (cdr list) | |
506 | list)) | |
507 | lists)))))) | |
508 | ||
509 | (export 'categorize) | |
510 | (defmacro categorize ((itemvar items &key bind) categories &body body) | |
511 | "Categorize ITEMS into lists and invoke BODY. | |
512 | ||
513 | The ITEMVAR is a symbol; as the macro iterates over the ITEMS, ITEMVAR | |
514 | will contain the current item. The BIND argument is a list of LET*-like | |
515 | clauses. The CATEGORIES are a list of clauses of the form (SYMBOL | |
516 | PREDICATE). | |
517 | ||
518 | The behaviour of the macro is as follows. ITEMVAR is assigned (not | |
519 | bound), in turn, each item in the list ITEMS. The PREDICATEs in the | |
520 | CATEGORIES list are evaluated in turn, in an environment containing | |
521 | ITEMVAR and the BINDings, until one of them evaluates to a non-nil value. | |
522 | At this point, the item is assigned to the category named by the | |
523 | corresponding SYMBOL. If none of the PREDICATEs returns non-nil then an | |
524 | error is signalled; a PREDICATE consisting only of T will (of course) | |
525 | match anything; it is detected specially so as to avoid compiler warnings. | |
526 | ||
527 | Once all of the ITEMS have been categorized in this fashion, the BODY is | |
528 | evaluated as an implicit PROGN. For each SYMBOL naming a category, a | |
529 | variable named after that symbol will be bound in the BODY's environment | |
530 | to a list of the items in that category, in the same order in which they | |
531 | were found in the list ITEMS. The final values of the macro are the final | |
532 | values of the BODY." | |
533 | ||
534 | (let* ((cat-names (mapcar #'car categories)) | |
535 | (cat-match-forms (mapcar #'cadr categories)) | |
536 | (cat-vars (mapcar (lambda (name) (gensym (concatenate 'string | |
537 | (symbol-name name) "-"))) | |
538 | cat-names)) | |
539 | (items-var (gensym "ITEMS-"))) | |
540 | `(let ((,items-var ,items) | |
541 | ,@(mapcar (lambda (cat-var) (list cat-var nil)) cat-vars)) | |
542 | (dolist (,itemvar ,items-var) | |
543 | (let* ,bind | |
544 | (cond ,@(mapcar (lambda (cat-match-form cat-var) | |
545 | `(,cat-match-form | |
546 | (push ,itemvar ,cat-var))) | |
547 | cat-match-forms cat-vars) | |
548 | ,@(and (not (member t cat-match-forms)) | |
549 | `((t (error "Failed to categorize ~A" ,itemvar))))))) | |
550 | (let ,(mapcar (lambda (name var) | |
551 | `(,name (nreverse ,var))) | |
552 | cat-names cat-vars) | |
553 | ,@body)))) | |
554 | ||
555 | ;;;-------------------------------------------------------------------------- | |
556 | ;;; Strings and characters. | |
557 | ||
558 | (export 'frob-identifier) | |
559 | (defun frob-identifier (string &key (swap-case t) (swap-hyphen t)) | |
560 | "Twiddles the case of STRING. | |
561 | ||
562 | If all the letters in STRING are uppercase, and SWAP-CASE is true, then | |
563 | switch them to lowercase; if they're all lowercase then switch them to | |
564 | uppercase. If there's a mix then leave them all alone. At the same time, | |
565 | if there are underscores but no hyphens, and SWAP-HYPHEN is true, then | |
566 | switch them to hyphens, if there are hyphens and no underscores, switch | |
567 | them underscores, and if there are both then leave them alone. | |
568 | ||
569 | This is an invertible transformation, which turns vaguely plausible Lisp | |
570 | names into vaguely plausible C names and vice versa. Lisp names with | |
571 | `funny characters' like stars and percent signs won't be any use, of | |
572 | course." | |
573 | ||
574 | ;; Work out what kind of a job we've got to do. Gather flags: bit 0 means | |
575 | ;; there are upper-case letters; bit 1 means there are lower-case letters; | |
576 | ;; bit 2 means there are hyphens; bit 3 means there are underscores. | |
577 | ;; | |
578 | ;; Consequently, (logxor flags (ash flags 1)) is interesting: bit 1 is set | |
579 | ;; if we have to frob case; bit 3 is set if we have to swap hyphens and | |
580 | ;; underscores. So use this to select functions which do bits of the | |
581 | ;; mapping, and then compose them together. | |
582 | (let* ((flags (reduce (lambda (state ch) | |
583 | (logior state | |
584 | (cond ((upper-case-p ch) 1) | |
585 | ((lower-case-p ch) 2) | |
586 | ((char= ch #\-) 4) | |
587 | ((char= ch #\_) 8) | |
588 | (t 0)))) | |
589 | string | |
590 | :initial-value 0)) | |
591 | (mask (logxor flags (ash flags 1))) | |
592 | (letter (cond ((or (not swap-case) (not (logbitp 1 mask))) | |
593 | (constantly nil)) | |
594 | ((logbitp 0 flags) | |
595 | (lambda (ch) | |
596 | (and (alpha-char-p ch) (char-downcase ch)))) | |
597 | (t | |
598 | (lambda (ch) | |
599 | (and (alpha-char-p ch) (char-upcase ch)))))) | |
600 | (uscore-hyphen (cond ((or (not (logbitp 3 mask)) (not swap-hyphen)) | |
601 | (constantly nil)) | |
602 | ((logbitp 2 flags) | |
603 | (lambda (ch) (and (char= ch #\-) #\_))) | |
604 | (t | |
605 | (lambda (ch) (and (char= ch #\_) #\-)))))) | |
606 | ||
607 | (if (logbitp 3 (logior mask (ash mask 2))) | |
608 | (map 'string (lambda (ch) | |
609 | (or (funcall letter ch) | |
610 | (funcall uscore-hyphen ch) | |
611 | ch)) | |
612 | string) | |
613 | string))) | |
614 | ||
615 | (export 'whitespace-char-p) | |
616 | (declaim (inline whitespace-char-p)) | |
617 | (defun whitespace-char-p (char) | |
618 | "Returns whether CHAR is a whitespace character. | |
619 | ||
620 | Whitespaceness is determined relative to the compile-time readtable, which | |
621 | is probably good enough for most purposes." | |
622 | (case char | |
623 | (#.(loop for i below char-code-limit | |
624 | for ch = (code-char i) | |
625 | unless (with-input-from-string (in (string ch)) | |
626 | (peek-char t in nil)) | |
627 | collect ch) t) | |
628 | (t nil))) | |
629 | ||
630 | (export 'update-position) | |
631 | (declaim (inline update-position)) | |
632 | (defun update-position (char line column) | |
633 | "Updates LINE and COLUMN appropriately for having read the character CHAR. | |
634 | ||
635 | Returns the new LINE and COLUMN numbers." | |
636 | (case char | |
637 | ((#\newline #\vt #\page) | |
638 | (values (1+ line) 0)) | |
639 | ((#\tab) | |
640 | (values line (logandc2 (+ column 8) 7))) | |
641 | (t | |
642 | (values line (1+ column))))) | |
643 | ||
644 | (export 'backtrack-position) | |
645 | (declaim (inline backtrack-position)) | |
646 | (defun backtrack-position (char line column) | |
647 | "Updates LINE and COLUMN appropriately for having unread CHAR. | |
648 | ||
649 | Well, actually an approximation for it; it will likely be wrong if the | |
650 | last character was a tab. But when the character is read again, it will | |
651 | be correct." | |
652 | ||
653 | ;; This isn't perfect: if the character doesn't actually match what was | |
654 | ;; really read then it might not actually be possible: for example, if we | |
655 | ;; push back a newline while in the middle of a line, or a tab while not at | |
656 | ;; a tab stop. In that case, we'll just lose, but hopefully not too badly. | |
657 | (case char | |
658 | ||
659 | ;; In the absence of better ideas, I'll set the column number to zero. | |
660 | ;; This is almost certainly wrong, but with a little luck nobody will ask | |
661 | ;; and it'll be all right soon. | |
662 | ((#\newline #\vt #\page) (values (1- line) 0)) | |
663 | ||
664 | ;; Winding back a single space is sufficient. If the position is | |
665 | ;; currently on a tab stop then it'll advance back here next time. If | |
666 | ;; not, we're going to lose anyway because the previous character | |
667 | ;; certainly couldn't have been a tab. | |
668 | (#\tab (values line (1- column))) | |
669 | ||
670 | ;; Anything else: just decrement the column and cross fingers. | |
671 | (t (values line (1- column))))) | |
672 | ||
673 | ;;;-------------------------------------------------------------------------- | |
674 | ;;; Functions. | |
675 | ||
676 | (export 'compose) | |
677 | (defun compose (function &rest more-functions) | |
678 | "Composition of functions. Functions are applied left-to-right. | |
679 | ||
680 | This is the reverse order of the usual mathematical notation, but I find | |
bf090e02 MW |
681 | it easier to read. It's also slightly easier to work with in programs. |
682 | That is, (compose F1 F2 ... Fn) is what a category theorist might write as | |
683 | F1 ; F2 ; ... ; Fn, rather than F1 o F2 o ... o Fn." | |
684 | ||
dea4d055 MW |
685 | (labels ((compose1 (func-a func-b) |
686 | (lambda (&rest args) | |
687 | (multiple-value-call func-b (apply func-a args))))) | |
688 | (reduce #'compose1 more-functions :initial-value function))) | |
689 | ||
690 | ;;;-------------------------------------------------------------------------- | |
691 | ;;; Symbols. | |
692 | ||
693 | (export 'symbolicate) | |
694 | (defun symbolicate (&rest symbols) | |
695 | "Return a symbol named after the concatenation of the names of the SYMBOLS. | |
696 | ||
3109662a | 697 | The symbol is interned in the current `*package*'. Trad." |
dea4d055 MW |
698 | (intern (apply #'concatenate 'string (mapcar #'symbol-name symbols)))) |
699 | ||
700 | ;;;-------------------------------------------------------------------------- | |
701 | ;;; Object printing. | |
702 | ||
703 | (export 'maybe-print-unreadable-object) | |
704 | (defmacro maybe-print-unreadable-object | |
705 | ((object stream &rest args) &body body) | |
706 | "Print helper for usually-unreadable objects. | |
707 | ||
3109662a | 708 | If `*print-escape*' is set then print OBJECT unreadably using BODY. |
dea4d055 MW |
709 | Otherwise just print using BODY." |
710 | (with-gensyms (print) | |
711 | `(flet ((,print () ,@body)) | |
712 | (if *print-escape* | |
713 | (print-unreadable-object (,object ,stream ,@args) | |
714 | (,print)) | |
715 | (,print))))) | |
716 | ||
08b6e064 MW |
717 | (export 'print-ugly-stuff) |
718 | (defun print-ugly-stuff (stream func) | |
719 | "Print not-pretty things to the stream underlying STREAM. | |
720 | ||
721 | The Lisp pretty-printing machinery, notably `pprint-logical-block', may | |
722 | interpose additional streams between its body and the original target | |
723 | stream. This makes it difficult to make use of the underlying stream's | |
724 | special features, whatever they might be." | |
725 | ||
726 | ;; This is unpleasant. Hacky hacky. | |
727 | #.(or #+sbcl '(if (typep stream 'sb-pretty:pretty-stream) | |
728 | (let ((target (sb-pretty::pretty-stream-target stream))) | |
729 | (pprint-newline :mandatory stream) | |
730 | (funcall func target)) | |
731 | (funcall func stream)) | |
732 | #+cmu '(if (typep stream 'pp:pretty-stream) | |
733 | (let ((target (pp::pretty-stream-target stream))) | |
734 | (pprint-newline :mandatory stream) | |
735 | (funcall func target)) | |
736 | (funcall func stream)) | |
737 | '(funcall func stream))) | |
738 | ||
dea4d055 MW |
739 | ;;;-------------------------------------------------------------------------- |
740 | ;;; Iteration macros. | |
741 | ||
742 | (export 'dosequence) | |
743 | (defmacro dosequence ((var seq &key (start 0) (end nil) indexvar) | |
744 | &body body | |
745 | &environment env) | |
746 | "Macro for iterating over general sequences. | |
747 | ||
748 | Iterates over a (sub)sequence SEQ, delimited by START and END (which are | |
749 | evaluated). For each item of SEQ, BODY is invoked with VAR bound to the | |
750 | item, and INDEXVAR (if requested) bound to the item's index. (Note that | |
751 | this is different from most iteration constructs in Common Lisp, which | |
752 | work by mutating the variable.) | |
753 | ||
754 | The loop is surrounded by an anonymous BLOCK and the loop body forms an | |
755 | implicit TAGBODY, as is usual. There is no result-form, however." | |
756 | ||
757 | (once-only (:environment env seq start end) | |
758 | (with-gensyms ((ivar "INDEX-") (endvar "END-") (bodyfunc "BODY-")) | |
b8c698ee MW |
759 | (multiple-value-bind (docs decls body) (parse-body body :docp nil) |
760 | (declare (ignore docs)) | |
761 | ||
762 | (flet ((loopguts (indexp listp endvar) | |
763 | ;; Build a DO-loop to do what we want. | |
764 | (let* ((do-vars nil) | |
765 | (end-condition (if endvar | |
766 | `(>= ,ivar ,endvar) | |
767 | `(endp ,seq))) | |
768 | (item (if listp | |
769 | `(car ,seq) | |
770 | `(aref ,seq ,ivar))) | |
771 | (body-call `(,bodyfunc ,item))) | |
772 | (when listp | |
773 | (push `(,seq (nthcdr ,start ,seq) (cdr ,seq)) | |
774 | do-vars)) | |
775 | (when indexp | |
776 | (push `(,ivar ,start (1+ ,ivar)) do-vars)) | |
777 | (when indexvar | |
778 | (setf body-call (append body-call (list ivar)))) | |
779 | `(do ,do-vars (,end-condition) ,body-call)))) | |
780 | ||
781 | `(block nil | |
782 | (flet ((,bodyfunc (,var ,@(and indexvar `(,indexvar))) | |
783 | ,@decls | |
784 | (tagbody ,@body))) | |
dea4d055 MW |
785 | (etypecase ,seq |
786 | (vector | |
787 | (let ((,endvar (or ,end (length ,seq)))) | |
788 | ,(loopguts t nil endvar))) | |
789 | (list | |
790 | (if ,end | |
791 | ,(loopguts t t end) | |
b8c698ee | 792 | ,(loopguts indexvar t nil))))))))))) |
dea4d055 MW |
793 | |
794 | ;;;-------------------------------------------------------------------------- | |
4b8e5c03 MW |
795 | ;;; Structure accessor hacks. |
796 | ||
797 | (export 'define-access-wrapper) | |
798 | (defmacro define-access-wrapper (from to &key read-only) | |
799 | "Make (FROM THING) work like (TO THING). | |
800 | ||
801 | If not READ-ONLY, then also make (setf (FROM THING) VALUE) work like | |
802 | (setf (TO THING) VALUE). | |
803 | ||
804 | This is mostly useful for structure slot accessors where the slot has to | |
805 | be given an unpleasant name to avoid it being an external symbol." | |
806 | `(progn | |
807 | (declaim (inline ,from ,@(and (not read-only) `((setf ,from))))) | |
808 | (defun ,from (object) | |
809 | (,to object)) | |
810 | ,@(and (not read-only) | |
811 | `((defun (setf ,from) (value object) | |
812 | (setf (,to object) value)))))) | |
813 | ||
814 | ;;;-------------------------------------------------------------------------- | |
dea4d055 MW |
815 | ;;; CLOS hacking. |
816 | ||
817 | (export 'default-slot) | |
818 | (defmacro default-slot ((instance slot &optional (slot-names t)) | |
819 | &body value | |
820 | &environment env) | |
821 | "If INSTANCE's slot named SLOT is unbound, set it to VALUE. | |
822 | ||
823 | Only set SLOT if it's listed in SLOT-NAMES, or SLOT-NAMES is `t' (i.e., we | |
824 | obey the `shared-initialize' protocol). SLOT-NAMES defaults to `t', so | |
825 | you can use it in `initialize-instance' or similar without ill effects. | |
826 | Both INSTANCE and SLOT are evaluated; VALUE is an implicit progn and only | |
827 | evaluated if it's needed." | |
828 | ||
829 | (once-only (:environment env instance slot slot-names) | |
830 | `(when ,(if (eq slot-names t) | |
831 | `(not (slot-boundp ,instance ,slot)) | |
832 | `(and (not (slot-boundp ,instance ,slot)) | |
833 | (or (eq ,slot-names t) | |
834 | (member ,slot ,slot-names)))) | |
835 | (setf (slot-value ,instance ,slot) | |
836 | (progn ,@value))))) | |
837 | ||
141283ff MW |
838 | (export 'define-on-demand-slot) |
839 | (defmacro define-on-demand-slot (class slot (instance) &body body) | |
840 | "Defines a slot which computes its initial value on demand. | |
841 | ||
842 | Sets up the named SLOT of CLASS to establish its value as the implicit | |
843 | progn BODY, by defining an appropriate method on `slot-unbound'." | |
b8c698ee MW |
844 | (multiple-value-bind (docs decls body) (parse-body body) |
845 | (with-gensyms (classvar slotvar) | |
846 | `(defmethod slot-unbound | |
847 | (,classvar (,instance ,class) (,slotvar (eql ',slot))) | |
848 | ,@docs ,@decls | |
849 | (declare (ignore ,classvar)) | |
fc09e191 | 850 | (setf (slot-value ,instance ',slot) (block ,slot ,@body)))))) |
141283ff | 851 | |
dea4d055 | 852 | ;;;----- That's all, folks -------------------------------------------------- |