Commit | Line | Data |
---|---|---|
861345b4 | 1 | ;;; -*-lisp-*- |
2 | ;;; | |
3 | ;;; $Id$ | |
4 | ;;; | |
5 | ;;; Basic definitions | |
6 | ;;; | |
7 | ;;; (c) 2005 Mark Wooding | |
8 | ;;; | |
9 | ||
10 | ;;;----- Licensing notice --------------------------------------------------- | |
11 | ;;; | |
12 | ;;; This program 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. | |
b2c12b4e | 16 | ;;; |
861345b4 | 17 | ;;; This program 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. | |
b2c12b4e | 21 | ;;; |
861345b4 | 22 | ;;; You should have received a copy of the GNU General Public License |
23 | ;;; along with this program; if not, write to the Free Software Foundation, | |
24 | ;;; Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
25 | ||
02866e07 MW |
26 | ;;;-------------------------------------------------------------------------- |
27 | ;;; Package things. | |
28 | ||
861345b4 | 29 | (defpackage #:mdw.base |
30 | (:use #:common-lisp) | |
23f32e98 MW |
31 | (:export #:unsigned-fixnum |
32 | #:compile-time-defun | |
861345b4 | 33 | #:show |
f5612edb MW |
34 | #:stringify #:functionify #:mappend |
35 | #:listify #:fix-pair #:pairify | |
8f801ae8 | 36 | #:parse-body #:with-parsed-body |
861345b4 | 37 | #:whitespace-char-p |
38 | #:slot-uninitialized | |
2af61873 | 39 | #:nlet #:while #:until #:case2 #:ecase2 #:setf-default |
861345b4 | 40 | #:with-gensyms #:let*/gensyms #:with-places |
e979e568 MW |
41 | #:locp #:locf #:ref #:with-locatives |
42 | #:update-place #:update-place-after | |
7dcf04ad MW |
43 | #:incf-after #:decf-after |
44 | #:fixnump) | |
45 | #+cmu (:import-from #:extensions #:fixnump)) | |
46 | ||
861345b4 | 47 | (in-package #:mdw.base) |
48 | ||
02866e07 | 49 | ;;;-------------------------------------------------------------------------- |
23f32e98 MW |
50 | ;;; Useful types. |
51 | ||
52 | (deftype unsigned-fixnum () | |
53 | "Unsigned fixnums; useful as array indices and suchlike." | |
54 | `(mod ,most-positive-fixnum)) | |
55 | ||
56 | ;;;-------------------------------------------------------------------------- | |
02866e07 MW |
57 | ;;; Some simple macros to get things going. |
58 | ||
861345b4 | 59 | (defmacro compile-time-defun (name args &body body) |
60 | "Define a function which can be used by macros during the compilation | |
0ff9df03 | 61 | process." |
fe0f07ea | 62 | `(eval-when (:compile-toplevel :load-toplevel :execute) |
861345b4 | 63 | (defun ,name ,args ,@body))) |
64 | ||
65 | (defmacro show (x) | |
2f94737a | 66 | "Debugging tool: print the expression X and its values." |
861345b4 | 67 | (let ((tmp (gensym))) |
2f94737a | 68 | `(let ((,tmp (multiple-value-list ,x))) |
f36fbd9c | 69 | (fresh-line) |
2f94737a MW |
70 | (pprint-logical-block (*standard-output* nil :per-line-prefix ";; ") |
71 | (format t | |
72 | "~S = ~@_~:I~:[#<no values>~;~:*~{~S~^ ~_~}~]" | |
73 | ',x | |
74 | ,tmp)) | |
75 | (terpri) | |
76 | (values-list ,tmp)))) | |
861345b4 | 77 | |
78 | (defun stringify (str) | |
79 | "Return a string representation of STR. Strings are returned unchanged; | |
0ff9df03 MW |
80 | symbols are converted to their names (unqualified!). Other objects are |
81 | converted to their print representations." | |
861345b4 | 82 | (typecase str |
83 | (string str) | |
84 | (symbol (symbol-name str)) | |
53e95db0 | 85 | (t (princ-to-string str)))) |
02866e07 | 86 | |
f5612edb MW |
87 | (defun functionify (func) |
88 | "Convert the function-designator FUNC to a function." | |
89 | (declare (type (or function symbol) func)) | |
90 | (etypecase func | |
91 | (function func) | |
92 | (symbol (symbol-function func)))) | |
93 | ||
4b6a6387 MW |
94 | (defun mappend (function list &rest more-lists) |
95 | "Apply FUNCTION to corresponding elements of LIST and MORE-LISTS, yielding | |
96 | a list. Return the concatenation of all the resulting lists. Like | |
97 | mapcan, but nondestructive." | |
98 | (apply #'append (apply #'mapcar function list more-lists))) | |
99 | ||
861345b4 | 100 | (compile-time-defun listify (x) |
101 | "If X is a (possibly empty) list, return X; otherwise return (list X)." | |
102 | (if (listp x) x (list x))) | |
02866e07 | 103 | |
861345b4 | 104 | (compile-time-defun do-fix-pair (x y defaultp) |
105 | "Helper function for fix-pair and pairify." | |
106 | (flet ((singleton (x) (values x (if defaultp y x)))) | |
107 | (cond ((atom x) (singleton x)) | |
108 | ((null (cdr x)) (singleton (car x))) | |
109 | ((atom (cdr x)) (values (car x) (cdr x))) | |
110 | ((cddr x) (error "Too many elements for a pair.")) | |
111 | (t (values (car x) (cadr x)))))) | |
02866e07 | 112 | |
861345b4 | 113 | (compile-time-defun fix-pair (x &optional (y nil defaultp)) |
114 | "Return two values extracted from X. It works as follows: | |
0ff9df03 MW |
115 | (A) -> A, Y |
116 | (A B) -> A, B | |
117 | (A B . C) -> error | |
118 | (A . B) -> A, B | |
119 | A -> A, Y | |
120 | where Y defaults to A if not specified." | |
861345b4 | 121 | (do-fix-pair x y defaultp)) |
02866e07 | 122 | |
861345b4 | 123 | (compile-time-defun pairify (x &optional (y nil defaultp)) |
124 | "As for fix-pair, but returns a list instead of two values." | |
125 | (multiple-value-call #'list (do-fix-pair x y defaultp))) | |
126 | ||
127 | (defun whitespace-char-p (ch) | |
128 | "Return whether CH is a whitespace character or not." | |
129 | (case ch | |
67cb6748 MW |
130 | (#.(loop for i below char-code-limit |
131 | for ch = (code-char i) | |
132 | unless (with-input-from-string (in (string ch)) | |
133 | (peek-char t in nil)) | |
134 | collect ch) | |
135 | t) | |
861345b4 | 136 | (t nil))) |
137 | ||
d6caa73b MW |
138 | (defmacro defconstant* (name value &key doc test) |
139 | "Define a constant, like `defconstant'. The TEST is an equality test used | |
140 | to decide whether to override the current definition, if any." | |
141 | (let ((temp (gensym))) | |
142 | `(eval-when (:compile-toplevel :load-toplevel :execute) | |
143 | (let ((,temp ,value)) | |
144 | (unless (and (boundp ',name) | |
145 | (funcall ,(or test ''eql) (symbol-value ',name) ,temp)) | |
146 | (defconstant ,name ,value ,@(and doc (list doc)))) | |
147 | ',name)))) | |
148 | ||
861345b4 | 149 | (declaim (ftype (function nil ()) slot-unitialized)) |
150 | (defun slot-uninitialized () | |
151 | "A function which signals an error. Can be used as an initializer form in | |
0ff9df03 | 152 | structure definitions without doom ensuing." |
861345b4 | 153 | (error "No initializer for slot.")) |
154 | ||
e2a3c923 | 155 | (compile-time-defun parse-body (body &key (allow-docstring-p t)) |
9d3ccec7 | 156 | "Given a BODY (a list of forms), parses it into three sections: a |
0ff9df03 MW |
157 | docstring, a list of declarations (forms beginning with the symbol |
158 | `declare') and the body forms. The result is returned as three lists | |
159 | (even the docstring), suitable for interpolation into a backquoted list | |
e2a3c923 MW |
160 | using `@,'. If ALLOW-DOCSTRING-P is nil, docstrings aren't allowed at |
161 | all." | |
162 | (let ((doc nil) (decls nil)) | |
163 | (do ((forms body (cdr forms))) (nil) | |
164 | (let ((form (and forms (car forms)))) | |
165 | (cond ((and allow-docstring-p (not doc) (stringp form) (cdr forms)) | |
166 | (setf doc form)) | |
167 | ((and (consp form) | |
168 | (eq (car form) 'declare)) | |
169 | (setf decls (append decls (cdr form)))) | |
170 | (t (return (values (and doc (list doc)) | |
171 | (and decls (list (cons 'declare decls))) | |
172 | forms)))))))) | |
9d3ccec7 | 173 | |
8f801ae8 MW |
174 | (defmacro with-parsed-body |
175 | ((bodyvar declvar &optional (docvar (gensym) docp)) form &body body) | |
176 | "Parse FORM into a body, declarations and (maybe) a docstring; bind BODYVAR | |
177 | to the body, DECLVAR to the declarations, and DOCVAR to (a list | |
178 | containing) the docstring, and evaluate BODY." | |
179 | `(multiple-value-bind | |
180 | (,docvar ,declvar ,bodyvar) | |
181 | (parse-body ,form :allow-docstring-p ,docp) | |
182 | ,@(if docp nil `((declare (ignore ,docvar)))) | |
183 | ,@body)) | |
184 | ||
7dcf04ad MW |
185 | #-cmu |
186 | (progn | |
187 | (declaim (inline fixnump)) | |
188 | (defun fixnump (object) | |
189 | "Answer non-nil if OBJECT is a fixnum, or nil if it isn't." | |
190 | (typep object 'fixnum))) | |
191 | ||
02866e07 MW |
192 | ;;;-------------------------------------------------------------------------- |
193 | ;;; Generating symbols. | |
194 | ||
861345b4 | 195 | (defmacro with-gensyms (syms &body body) |
196 | "Everyone's favourite macro helper." | |
197 | `(let (,@(mapcar (lambda (sym) `(,sym (gensym ,(symbol-name sym)))) | |
198 | (listify syms))) | |
199 | ,@body)) | |
200 | ||
201 | (defmacro let*/gensyms (binds &body body) | |
202 | "A macro helper. BINDS is a list of binding pairs (VAR VALUE), where VALUE | |
0ff9df03 MW |
203 | defaults to VAR. The result is that BODY is evaluated in a context where |
204 | each VAR is bound to a gensym, and in the final expansion, each of those | |
205 | gensyms will be bound to the corresponding VALUE." | |
861345b4 | 206 | (labels ((more (binds) |
207 | (let ((tmp (gensym "TMP")) (bind (car binds))) | |
208 | `((let ((,tmp ,(cadr bind)) | |
209 | (,(car bind) (gensym ,(symbol-name (car bind))))) | |
210 | `(let ((,,(car bind) ,,tmp)) | |
211 | ,,@(if (cdr binds) | |
212 | (more (cdr binds)) | |
213 | body))))))) | |
214 | (if (null binds) | |
215 | `(progn ,@body) | |
216 | (car (more (mapcar #'pairify (listify binds))))))) | |
217 | ||
02866e07 | 218 | ;;;-------------------------------------------------------------------------- |
f2d46aaa MW |
219 | ;;; Some simple yet useful control structures. |
220 | ||
221 | (defmacro nlet (name binds &body body) | |
222 | "Scheme's named let." | |
223 | (multiple-value-bind (vars vals) | |
224 | (loop for bind in binds | |
225 | for (var val) = (pairify bind nil) | |
226 | collect var into vars | |
227 | collect val into vals | |
228 | finally (return (values vars vals))) | |
229 | `(labels ((,name ,vars | |
230 | ,@body)) | |
231 | (,name ,@vals)))) | |
232 | ||
233 | (defmacro while (cond &body body) | |
234 | "If COND is false, evaluate to nil; otherwise evaluate BODY and try again." | |
38ccae7f MW |
235 | `(loop (unless ,cond (return)) (progn ,@body))) |
236 | ||
237 | (defmacro until (cond &body body) | |
238 | "If COND is true, evaluate to nil; otherwise evaluate BODY and try again." | |
239 | `(loop (when ,cond (return)) (progn ,@body))) | |
f2d46aaa | 240 | |
560e1186 MW |
241 | (compile-time-defun do-case2-like (kind vform clauses) |
242 | "Helper function for `case2' and `ecase2'." | |
243 | (with-gensyms (scrutinee argument) | |
244 | `(multiple-value-bind (,scrutinee ,argument) ,vform | |
245 | (declare (ignorable ,argument)) | |
246 | (,kind ,scrutinee | |
247 | ,@(mapcar (lambda (clause) | |
248 | (destructuring-bind | |
b3bc3745 | 249 | (cases (&optional varx vary) &rest forms) |
560e1186 MW |
250 | clause |
251 | `(,cases | |
b3bc3745 MW |
252 | ,@(if varx |
253 | (list `(let ((,(or vary varx) ,argument) | |
254 | ,@(and vary | |
255 | `((,varx ,scrutinee)))) | |
256 | ,@forms)) | |
560e1186 MW |
257 | forms)))) |
258 | clauses))))) | |
259 | ||
260 | (defmacro case2 (vform &body clauses) | |
261 | "VFORM is a form which evaluates to two values, SCRUTINEE and ARGUMENT. | |
b3bc3745 MW |
262 | The CLAUSES have the form (CASES ([[SCRUVAR] ARGVAR]) FORMS...), where a |
263 | standard `case' clause has the form (CASES FORMS...). The `case2' form | |
264 | evaluates the VFORM, and compares the SCRUTINEE to the various CASES, in | |
265 | order, just like `case'. If there is a match, then the corresponding | |
266 | FORMs are evaluated with ARGVAR bound to the ARGUMENT and SCRUVAR bound to | |
267 | the SCRUTINEE (where specified). Note the bizarre defaulting behaviour: | |
268 | ARGVAR is less optional than SCRUVAR." | |
560e1186 MW |
269 | (do-case2-like 'case vform clauses)) |
270 | ||
271 | (defmacro ecase2 (vform &body clauses) | |
272 | "Like `case2', but signals an error if no clause matches the SCRUTINEE." | |
273 | (do-case2-like 'ecase vform clauses)) | |
274 | ||
2af61873 MW |
275 | (defmacro setf-default (&rest specs &environment env) |
276 | "Like setf, but only sets places which are currently nil. | |
277 | ||
278 | The arguments are an alternating list of PLACEs and DEFAULTs. If a PLACE | |
279 | is nil, the DEFAULT is evaluated and stored in the PLACE; otherwise the | |
280 | default is /not/ stored. The result is the (new) value of the last | |
281 | PLACE." | |
282 | (labels ((doit (specs) | |
283 | (cond ((null specs) nil) | |
284 | ((null (cdr specs)) | |
285 | (error "Odd number of arguments for SETF-DEFAULT.")) | |
286 | (t | |
287 | (let ((place (car specs)) | |
288 | (default (cadr specs)) | |
289 | (rest (cddr specs))) | |
290 | (multiple-value-bind | |
291 | (vars vals store-vals writer reader) | |
292 | (get-setf-expansion place env) | |
293 | `(let* ,(mapcar #'list vars vals) | |
294 | (or ,reader | |
295 | (multiple-value-bind ,store-vals ,default | |
296 | ,writer)) | |
297 | ,@(and rest (list (doit rest)))))))))) | |
298 | (doit specs))) | |
299 | ||
f2d46aaa | 300 | ;;;-------------------------------------------------------------------------- |
02866e07 MW |
301 | ;;; with-places |
302 | ||
861345b4 | 303 | (defmacro %place-ref (getform setform newtmp) |
304 | "Grim helper macro for with-places." | |
305 | (declare (ignore setform newtmp)) | |
306 | getform) | |
02866e07 | 307 | |
861345b4 | 308 | (define-setf-expander %place-ref (getform setform newtmp) |
309 | "Grim helper macro for with-places." | |
310 | (values nil nil newtmp setform getform)) | |
02866e07 | 311 | |
861345b4 | 312 | (defmacro with-places ((&key environment) places &body body) |
313 | "A hairy helper, for writing setf-like macros. PLACES is a list of binding | |
0ff9df03 MW |
314 | pairs (VAR PLACE), where PLACE defaults to VAR. The result is that BODY |
315 | is evaluated in a context where each VAR is bound to a gensym, and in the | |
316 | final expansion, each of those gensyms will be bound to a symbol-macro | |
317 | capable of reading or setting the value of the corresponding PLACE." | |
861345b4 | 318 | (if (null places) |
319 | `(progn ,@body) | |
320 | (let*/gensyms (environment) | |
321 | (labels | |
322 | ((more (places) | |
323 | (let ((place (car places))) | |
324 | (with-gensyms (tmp valtmps valforms | |
325 | newtmps setform getform) | |
326 | `((let ((,tmp ,(cadr place)) | |
327 | (,(car place) | |
328 | (gensym ,(symbol-name (car place))))) | |
329 | (multiple-value-bind | |
330 | (,valtmps ,valforms | |
331 | ,newtmps ,setform ,getform) | |
332 | (get-setf-expansion ,tmp | |
333 | ,environment) | |
334 | (list 'let* | |
335 | (mapcar #'list ,valtmps ,valforms) | |
336 | `(symbol-macrolet ((,,(car place) | |
337 | (%place-ref ,,getform | |
338 | ,,setform | |
339 | ,,newtmps))) | |
340 | ,,@(if (cdr places) | |
341 | (more (cdr places)) | |
342 | body)))))))))) | |
343 | (car (more (mapcar #'pairify (listify places)))))))) | |
344 | ||
02866e07 MW |
345 | ;;;-------------------------------------------------------------------------- |
346 | ;;; Update-in-place macros built using with-places. | |
347 | ||
e979e568 MW |
348 | (defmacro update-place (op place arg &environment env) |
349 | "Update PLACE with the value of OP PLACE ARG, returning the new value." | |
350 | (with-places (:environment env) (place) | |
351 | `(setf ,place (,op ,place ,arg)))) | |
02866e07 | 352 | |
e979e568 MW |
353 | (defmacro update-place-after (op place arg &environment env) |
354 | "Update PLACE with the value of OP PLACE ARG, returning the old value." | |
355 | (with-places (:environment env) (place) | |
356 | (with-gensyms (x) | |
357 | `(let ((,x ,place)) | |
02866e07 MW |
358 | (setf ,place (,op ,x ,arg)) |
359 | ,x)))) | |
360 | ||
e979e568 MW |
361 | (defmacro incf-after (place &optional (by 1)) |
362 | "Increment PLACE by BY, returning the old value." | |
363 | `(update-place-after + ,place ,by)) | |
02866e07 | 364 | |
e979e568 MW |
365 | (defmacro decf-after (place &optional (by 1)) |
366 | "Decrement PLACE by BY, returning the old value." | |
367 | `(update-place-after - ,place ,by)) | |
368 | ||
02866e07 MW |
369 | ;;;-------------------------------------------------------------------------- |
370 | ;;; Locatives. | |
e979e568 | 371 | |
861345b4 | 372 | (defstruct (loc (:predicate locp) (:constructor make-loc (reader writer))) |
373 | "Locative data type. See `locf' and `ref'." | |
374 | (reader (slot-uninitialized) :type function) | |
375 | (writer (slot-uninitialized) :type function)) | |
02866e07 | 376 | |
861345b4 | 377 | (defmacro locf (place &environment env) |
378 | "Slightly cheesy locatives. (locf PLACE) returns an object which, using | |
0ff9df03 MW |
379 | the `ref' function, can be used to read or set the value of PLACE. It's |
380 | cheesy because it uses closures rather than actually taking the address of | |
381 | something. Also, unlike Zetalisp, we don't overload `car' to do our dirty | |
382 | work." | |
861345b4 | 383 | (multiple-value-bind |
384 | (valtmps valforms newtmps setform getform) | |
385 | (get-setf-expansion place env) | |
386 | `(let* (,@(mapcar #'list valtmps valforms)) | |
387 | (make-loc (lambda () ,getform) | |
388 | (lambda (,@newtmps) ,setform))))) | |
02866e07 | 389 | |
861345b4 | 390 | (declaim (inline loc (setf loc))) |
02866e07 | 391 | |
861345b4 | 392 | (defun ref (loc) |
393 | "Fetch the value referred to by a locative." | |
394 | (funcall (loc-reader loc))) | |
02866e07 | 395 | |
861345b4 | 396 | (defun (setf ref) (new loc) |
397 | "Store a new value in the place referred to by a locative." | |
398 | (funcall (loc-writer loc) new)) | |
02866e07 | 399 | |
861345b4 | 400 | (defmacro with-locatives (locs &body body) |
401 | "LOCS is a list of items of the form (SYM [LOC-EXPR]), where SYM is a | |
0ff9df03 MW |
402 | symbol and LOC-EXPR evaluates to a locative. If LOC-EXPR is omitted, it |
403 | defaults to SYM. As an abbreviation for a common case, LOCS may be a | |
404 | symbol instead of a list. The BODY is evaluated in an environment where | |
405 | each SYM is a symbol macro which expands to (ref LOC-EXPR) -- or, in fact, | |
406 | something similar which doesn't break if LOC-EXPR has side-effects. Thus, | |
407 | references, including `setf' forms, fetch or modify the thing referred to | |
408 | by the LOC-EXPR. Useful for covering over where something uses a | |
409 | locative." | |
861345b4 | 410 | (setf locs (mapcar #'pairify (listify locs))) |
411 | (let ((tt (mapcar (lambda (l) (declare (ignore l)) (gensym)) locs)) | |
412 | (ll (mapcar #'cadr locs)) | |
413 | (ss (mapcar #'car locs))) | |
414 | `(let (,@(mapcar (lambda (tmp loc) `(,tmp ,loc)) tt ll)) | |
415 | (symbol-macrolet (,@(mapcar (lambda (sym tmp) | |
416 | `(,sym (ref ,tmp))) ss tt)) | |
417 | ,@body)))) | |
418 | ||
419 | ;;;----- That's all, folks -------------------------------------------------- |