1 ;;;; lots of basic macros for the target SBCL
3 ;;;; This software is part of the SBCL system. See the README file for
6 ;;;; This software is derived from the CMU CL system, which was
7 ;;;; written at Carnegie Mellon University and released into the
8 ;;;; public domain. The software is in the public domain and is
9 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
10 ;;;; files for more information.
12 (in-package "SB!IMPL")
14 ;;;; ASSERT and CHECK-TYPE
16 ;;; ASSERT is written this way, to call ASSERT-ERROR, because of how
17 ;;; closures are compiled. RESTART-CASE has forms with closures that
18 ;;; the compiler causes to be generated at the top of any function
19 ;;; using RESTART-CASE, regardless of whether they are needed. Thus if
20 ;;; we just wrapped a RESTART-CASE around the call to ERROR, we'd have
21 ;;; to do a significant amount of work at runtime allocating and
22 ;;; deallocating the closures regardless of whether they were ever
25 ;;; ASSERT-ERROR isn't defined until a later file because it uses the
26 ;;; macro RESTART-CASE, which isn't defined until a later file.
27 (defmacro-mundanely assert (test-form &optional places datum &rest arguments)
29 "Signals an error if the value of test-form is nil. Continuing from this
30 error using the CONTINUE restart will allow the user to alter the value of
31 some locations known to SETF, starting over with test-form. Returns NIL."
33 (assert-error ',test-form ',places ,datum ,@arguments)
34 ,@(mapcar #'(lambda (place)
35 `(setf ,place (assert-prompt ',place ,place)))
38 (defun assert-prompt (name value)
39 (cond ((y-or-n-p "The old value of ~S is ~S.~
40 ~%Do you want to supply a new value? "
42 (format *query-io* "~&Type a form to be evaluated:~%")
43 (flet ((read-it () (eval (read *query-io*))))
44 (if (symbolp name) ;help user debug lexical variables
45 (progv (list name) (list value) (read-it))
49 ;;; CHECK-TYPE is written this way, to call CHECK-TYPE-ERROR, because
50 ;;; of how closures are compiled. RESTART-CASE has forms with closures
51 ;;; that the compiler causes to be generated at the top of any
52 ;;; function using RESTART-CASE, regardless of whether they are
53 ;;; needed. Because it would be nice if CHECK-TYPE were cheap to use,
54 ;;; and some things (e.g., READ-CHAR) can't afford this excessive
55 ;;; consing, we bend backwards a little.
57 ;;; FIXME: In reality, this restart cruft is needed hardly anywhere in
58 ;;; the system. Write NEED and NEED-TYPE to replace ASSERT and
59 ;;; CHECK-TYPE inside the system. (CL:CHECK-TYPE must still be
60 ;;; defined, since it's specified by ANSI and it is sometimes nice for
61 ;;; whipping up little things. But as far as I can tell it's not
62 ;;; usually very helpful deep inside the guts of a complex system like
65 ;;; CHECK-TYPE-ERROR isn't defined until a later file because it uses
66 ;;; the macro RESTART-CASE, which isn't defined until a later file.
67 (defmacro-mundanely check-type (place type &optional type-string)
69 "Signal a restartable error of type TYPE-ERROR if the value of PLACE is
70 not of the specified type. If an error is signalled and the restart is
71 used to return, this can only return if the STORE-VALUE restart is
72 invoked. In that case it will store into PLACE and start over."
73 (let ((place-value (gensym)))
74 `(do ((,place-value ,place ,place))
75 ((typep ,place-value ',type))
77 (check-type-error ',place ,place-value ',type ,type-string)))))
81 (defmacro-mundanely defconstant (name value &optional documentation)
83 "For defining global constants. DEFCONSTANT says that the value is
84 constant and may be compiled into code. If the variable already has
85 a value, and this is not EQL to the init, the code is not portable
86 (undefined behavior). The third argument is an optional documentation
87 string for the variable."
88 `(eval-when (:compile-toplevel :load-toplevel :execute)
89 (sb!c::%defconstant ',name ,value ',documentation)))
91 ;;; the guts of DEFCONSTANT
92 (defun sb!c::%defconstant (name value doc)
93 (unless (symbolp name)
94 (error "The constant name is not a symbol: ~S" name))
95 (about-to-modify name)
96 (let ((kind (info :variable :kind name)))
99 ;; Note: This behavior (discouraging any non-EQL modification)
100 ;; is unpopular, but it is specified by ANSI (i.e. ANSI says a
101 ;; non-EQL change has undefined consequences). If people really
102 ;; want bindings which are constant in some sense other than
103 ;; EQL, I suggest either just using DEFVAR (which is usually
104 ;; appropriate, despite the un-mnemonic name), or defining
105 ;; something like SB-INT:DEFCONSTANT-EQX (which is occasionally
106 ;; more appropriate). -- WHN 2000-11-03
108 (info :variable :constant-value name))
109 (cerror "Go ahead and change the value."
110 "The constant ~S is being redefined."
113 ;; (This is OK -- undefined variables are of this kind. So we
114 ;; don't warn or error or anything, just fall through.)
116 (t (warn "redefining ~(~A~) ~S to be a constant" kind name))))
118 (setf (fdocumentation name 'variable) doc))
120 ;; We want to set the cross-compilation host's symbol value, not just
121 ;; the cross-compiler's (INFO :VARIABLE :CONSTANT-VALUE NAME), so
123 ;; (defconstant max-entries 61)
124 ;; (deftype entry-index () `(mod ,max-entries))
125 ;; will be cross-compiled correctly.
126 #-sb-xc-host (setf (symbol-value name) value)
128 (/show (symbol-package name))
129 ;; Redefining our cross-compilation host's CL symbols
130 ;; would be poor form.
132 ;; FIXME: Having to check this and then not treat it
133 ;; as a fatal error seems like a symptom of things
134 ;; being pretty broken. It's also a problem in and of
135 ;; itself, since it makes it too easy for cases of
136 ;; using the cross-compilation host Lisp's CL
137 ;; constant values in the target Lisp to slip by. I
138 ;; got backed into this because the cross-compiler
139 ;; translates DEFCONSTANT SB!XC:FOO into DEFCONSTANT
140 ;; CL:FOO. It would be good to unscrew the
141 ;; cross-compilation package hacks so that that
142 ;; translation doesn't happen. Perhaps:
143 ;; * Replace SB-XC with SB-CL. SB-CL exports all the
144 ;; symbols which ANSI requires to be exported from CL.
145 ;; * Make a nickname SB!CL which behaves like SB!XC.
146 ;; * Go through the loaded-on-the-host code making
147 ;; every target definition be in SB-CL. E.g.
148 ;; DEFMACRO-MUNDANELY DEFCONSTANT becomes
149 ;; DEFMACRO-MUNDANELY SB!CL:DEFCONSTANT.
150 ;; * Make IN-TARGET-COMPILATION-MODE do
151 ;; UNUSE-PACKAGE CL and USE-PACKAGE SB-CL in each
152 ;; of the target packages (then undo it on exit).
153 ;; * Make the cross-compiler's implementation of
154 ;; EVAL-WHEN (:COMPILE-TOPLEVEL) do UNCROSS.
155 ;; (This may not require any change.)
156 ;; * Hack GENESIS as necessary so that it outputs
157 ;; SB-CL stuff as COMMON-LISP stuff.
158 ;; * Now the code here can assert that the symbol
159 ;; being defined isn't in the cross-compilation
160 ;; host's CL package.
161 (unless (eql (find-symbol (symbol-name name) :cl) name)
162 ;; KLUDGE: In the cross-compiler, we use the
163 ;; cross-compilation host's DEFCONSTANT macro
164 ;; instead of just (SETF SYMBOL-VALUE), in order to
165 ;; get whatever blessing the cross-compilation host
166 ;; may expect for a global (SETF SYMBOL-VALUE).
167 ;; (CMU CL, at least around 2.4.19, generated full
168 ;; WARNINGs for code -- e.g. DEFTYPE expanders --
169 ;; which referred to symbols which had been set by
170 ;; (SETF SYMBOL-VALUE). I doubt such warnings are
171 ;; ANSI-compliant, but I'm not sure, so I've
172 ;; written this in a way that CMU CL will tolerate
173 ;; and which ought to work elsewhere too.) -- WHN
175 (eval `(defconstant ,name ',value))))
177 (setf (info :variable :kind name) :constant)
178 (setf (info :variable :constant-value name) value)
181 ;;;; DEFINE-COMPILER-MACRO
183 ;;; FIXME: The logic here for handling compiler macros named (SETF
184 ;;; FOO) was added after the fork from SBCL, is not well tested, and
185 ;;; may conflict with subtleties of the ANSI standard. E.g. section
186 ;;; "3.2.2.1 Compiler Macros" says that creating a lexical binding for
187 ;;; a function name shadows a compiler macro, and it's not clear that
188 ;;; that works with this version. It should be tested.
189 (defmacro-mundanely define-compiler-macro (name lambda-list &body body)
191 "Define a compiler-macro for NAME."
192 (let ((whole (gensym "WHOLE-"))
193 (environment (gensym "ENV-")))
194 (multiple-value-bind (body local-decs doc)
195 (parse-defmacro lambda-list whole body name 'define-compiler-macro
196 :environment environment)
197 (let ((def `(lambda (,whole ,environment)
199 (block ,(function-name-block-name name)
201 `(sb!c::%define-compiler-macro ',name #',def ',lambda-list ,doc)))))
202 (defun sb!c::%define-compiler-macro (name definition lambda-list doc)
203 ;; FIXME: Why does this have to be an interpreted function? Shouldn't
205 (aver (sb!eval:interpreted-function-p definition))
206 (setf (sb!eval:interpreted-function-name definition)
207 (format nil "DEFINE-COMPILER-MACRO ~S" name))
208 (setf (sb!eval:interpreted-function-arglist definition) lambda-list)
209 (sb!c::%%define-compiler-macro name definition doc))
210 (defun sb!c::%%define-compiler-macro (name definition doc)
211 (setf (sb!xc:compiler-macro-function name) definition)
212 ;; FIXME: Add support for (SETF FDOCUMENTATION) when object is a list
213 ;; and type is COMPILER-MACRO. (Until then, we have to discard any
214 ;; compiler macro documentation for (SETF FOO).)
216 (setf (fdocumentation name 'compiler-macro) doc))
219 ;;;; CASE, TYPECASE, and friends
221 (eval-when (:compile-toplevel :load-toplevel :execute)
223 ;;; CASE-BODY returns code for all the standard "case" macros. NAME is
224 ;;; the macro name, and KEYFORM is the thing to case on. MULTI-P
225 ;;; indicates whether a branch may fire off a list of keys; otherwise,
226 ;;; a key that is a list is interpreted in some way as a single key.
227 ;;; When MULTI-P, TEST is applied to the value of KEYFORM and each key
228 ;;; for a given branch; otherwise, TEST is applied to the value of
229 ;;; KEYFORM and the entire first element, instead of each part, of the
230 ;;; case branch. When ERRORP, no T or OTHERWISE branch is permitted,
231 ;;; and an ERROR form is generated. When PROCEEDP, it is an error to
232 ;;; omit ERRORP, and the ERROR form generated is executed within a
233 ;;; RESTART-CASE allowing KEYFORM to be set and retested.
234 (defun case-body (name keyform cases multi-p test errorp proceedp needcasesp)
235 (unless (or cases (not needcasesp))
236 (warn "no clauses in ~S" name))
237 (let ((keyform-value (gensym))
241 (unless (list-of-length-at-least-p case 1)
242 (error "~S -- bad clause in ~S" case name))
243 (destructuring-bind (keyoid &rest forms) case
244 (cond ((memq keyoid '(t otherwise))
246 (error 'simple-program-error
248 "No default clause is allowed in ~S: ~S"
249 :format-arguments (list name case))
250 (push `(t nil ,@forms) clauses)))
251 ((and multi-p (listp keyoid))
252 (setf keys (append keyoid keys))
253 (push `((or ,@(mapcar (lambda (key)
254 `(,test ,keyform-value ',key))
261 (push `((,test ,keyform-value ',keyoid)
265 (case-body-aux name keyform keyform-value clauses keys errorp proceedp
266 `(,(if multi-p 'member 'or) ,@keys))))
268 ;;; CASE-BODY-AUX provides the expansion once CASE-BODY has groveled
269 ;;; all the cases. Note: it is not necessary that the resulting code
270 ;;; signal case-failure conditions, but that's what KMP's prototype
271 ;;; code did. We call CASE-BODY-ERROR, because of how closures are
272 ;;; compiled. RESTART-CASE has forms with closures that the compiler
273 ;;; causes to be generated at the top of any function using the case
274 ;;; macros, regardless of whether they are needed.
276 ;;; The CASE-BODY-ERROR function is defined later, when the
277 ;;; RESTART-CASE macro has been defined.
278 (defun case-body-aux (name keyform keyform-value clauses keys
279 errorp proceedp expected-type)
281 (let ((block (gensym))
283 `(let ((,keyform-value ,keyform))
289 (cond ,@(nreverse clauses)
294 ',name ',keyform ,keyform-value
295 ',expected-type ',keys)))
297 `(let ((,keyform-value ,keyform))
298 (declare (ignorable ,keyform-value)) ; e.g. (CASE KEY (T))
302 `((t (error 'case-failure
304 :datum ,keyform-value
305 :expected-type ',expected-type
306 :possibilities ',keys))))))))
309 (defmacro-mundanely case (keyform &body cases)
311 "CASE Keyform {({(Key*) | Key} Form*)}*
312 Evaluates the Forms in the first clause with a Key EQL to the value of
313 Keyform. If a singleton key is T then the clause is a default clause."
314 (case-body 'case keyform cases t 'eql nil nil nil))
316 (defmacro-mundanely ccase (keyform &body cases)
318 "CCASE Keyform {({(Key*) | Key} Form*)}*
319 Evaluates the Forms in the first clause with a Key EQL to the value of
320 Keyform. If none of the keys matches then a correctable error is
322 (case-body 'ccase keyform cases t 'eql t t t))
324 (defmacro-mundanely ecase (keyform &body cases)
326 "ECASE Keyform {({(Key*) | Key} Form*)}*
327 Evaluates the Forms in the first clause with a Key EQL to the value of
328 Keyform. If none of the keys matches then an error is signalled."
329 (case-body 'ecase keyform cases t 'eql t nil t))
331 (defmacro-mundanely typecase (keyform &body cases)
333 "TYPECASE Keyform {(Type Form*)}*
334 Evaluates the Forms in the first clause for which TYPEP of Keyform and Type
336 (case-body 'typecase keyform cases nil 'typep nil nil nil))
338 (defmacro-mundanely ctypecase (keyform &body cases)
340 "CTYPECASE Keyform {(Type Form*)}*
341 Evaluates the Forms in the first clause for which TYPEP of Keyform and Type
342 is true. If no form is satisfied then a correctable error is signalled."
343 (case-body 'ctypecase keyform cases nil 'typep t t t))
345 (defmacro-mundanely etypecase (keyform &body cases)
347 "ETYPECASE Keyform {(Type Form*)}*
348 Evaluates the Forms in the first clause for which TYPEP of Keyform and Type
349 is true. If no form is satisfied then an error is signalled."
350 (case-body 'etypecase keyform cases nil 'typep t nil t))
352 ;;;; WITH-FOO i/o-related macros
354 (defmacro-mundanely with-open-stream ((var stream) &body forms-decls)
355 (multiple-value-bind (forms decls) (parse-body forms-decls nil)
356 (let ((abortp (gensym)))
357 `(let ((,var ,stream)
361 (multiple-value-prog1
365 (close ,var :abort ,abortp)))))))
367 (defmacro-mundanely with-open-file ((stream filespec &rest options)
369 `(with-open-stream (,stream (open ,filespec ,@options))
372 (defmacro-mundanely with-input-from-string ((var string &key index start end)
374 (multiple-value-bind (forms decls) (parse-body forms-decls nil)
375 ;; The ONCE-ONLY inhibits compiler note for unreachable code when
377 (once-only ((string string))
380 `(make-string-input-stream ,string ,(or start 0)))
383 (make-string-input-stream ,string
386 (make-string-input-stream ,string
389 `(make-string-input-stream ,string
397 `((setf ,index (string-input-stream-current ,var)))))))))
399 (defmacro-mundanely with-output-to-string ((var &optional string)
401 (multiple-value-bind (forms decls) (parse-body forms-decls nil)
403 `(let ((,var (make-fill-pointer-output-stream ,string)))
408 `(let ((,var (make-string-output-stream)))
413 (get-output-stream-string ,var)))))
415 ;;;; miscellaneous macros
417 (defmacro-mundanely nth-value (n form)
419 "Evaluates FORM and returns the Nth value (zero based). This involves no
420 consing when N is a trivial constant integer."
422 (let ((dummy-list nil)
423 (keeper (gensym "KEEPER-")))
424 ;; We build DUMMY-LIST, a list of variables to bind to useless
425 ;; values, then we explicitly IGNORE those bindings and return
426 ;; KEEPER, the only thing we're really interested in right now.
428 (push (gensym "IGNORE-") dummy-list))
429 `(multiple-value-bind (,@dummy-list ,keeper) ,form
430 (declare (ignore ,@dummy-list))
433 `(case (the fixnum ,n)
434 (0 (nth-value 0 ,form))
435 (1 (nth-value 1 ,form))
436 (2 (nth-value 2 ,form))
437 (t (nth (the fixnum ,n) (multiple-value-list ,form)))))))
439 (defmacro-mundanely declaim (&rest specs)
441 "DECLAIM Declaration*
442 Do a declaration or declarations for the global environment."
444 `(eval-when (:compile-toplevel :load-toplevel :execute)
445 ,@(mapcar #'(lambda (x)
446 `(sb!xc:proclaim ',x))
448 ;; KLUDGE: The definition above doesn't work in the cross-compiler,
449 ;; because UNCROSS translates SB!XC:PROCLAIM into CL:PROCLAIM before
450 ;; the form gets executed. Instead, we have to explicitly do the
451 ;; proclamation at macroexpansion time. -- WHN ca. 19990810
453 ;; FIXME: Maybe we don't need this special treatment any more now
454 ;; that we're using DEFMACRO-MUNDANELY instead of DEFMACRO?
456 (mapcar #'sb!xc:proclaim specs)
458 ,@(mapcar #'(lambda (x)
459 `(sb!xc:proclaim ',x))
462 (defmacro-mundanely print-unreadable-object ((object stream
465 `(%print-unreadable-object ,object ,stream ,type ,identity
467 `#'(lambda () ,@body)