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 "Define a global constant, saying that the value is constant and may be
84 compiled into code. If the variable already has a value, and this is not
85 EQL to the new value, the code is not portable (undefined behavior). The
86 third argument is an optional documentation string for the variable."
87 `(eval-when (:compile-toplevel :load-toplevel :execute)
88 (sb!c::%defconstant ',name ,value ',documentation)))
90 ;;; the guts of DEFCONSTANT
91 (defun sb!c::%defconstant (name value doc)
92 (unless (symbolp name)
93 (error "The constant name is not a symbol: ~S" name))
94 (about-to-modify-symbol-value name)
95 (when (looks-like-name-of-special-var-p name)
96 (style-warn "defining ~S as a constant, even though the name follows~@
97 the usual naming convention (names like *FOO*) for special variables"
99 (let ((kind (info :variable :kind name)))
102 ;; Note: This behavior (discouraging any non-EQL modification)
103 ;; is unpopular, but it is specified by ANSI (i.e. ANSI says a
104 ;; non-EQL change has undefined consequences). If people really
105 ;; want bindings which are constant in some sense other than
106 ;; EQL, I suggest either just using DEFVAR (which is usually
107 ;; appropriate, despite the un-mnemonic name), or defining
108 ;; something like the DEFCONSTANT-EQX macro used in SBCL (which
109 ;; is occasionally more appropriate). -- WHN 2001-12-21
111 (info :variable :constant-value name))
112 (cerror "Go ahead and change the value."
113 "The constant ~S is being redefined."
116 ;; (This is OK -- undefined variables are of this kind. So we
117 ;; don't warn or error or anything, just fall through.)
119 (t (warn "redefining ~(~A~) ~S to be a constant" kind name))))
121 (setf (fdocumentation name 'variable) doc))
123 ;; We want to set the cross-compilation host's symbol value, not just
124 ;; the cross-compiler's (INFO :VARIABLE :CONSTANT-VALUE NAME), so
126 ;; (defconstant max-entries 61)
127 ;; (deftype entry-index () `(mod ,max-entries))
128 ;; will be cross-compiled correctly.
129 #-sb-xc-host (setf (symbol-value name) value)
131 ;; Redefining our cross-compilation host's CL symbols
132 ;; would be poor form.
134 ;; FIXME: Having to check this and then not treat it
135 ;; as a fatal error seems like a symptom of things
136 ;; being pretty broken. It's also a problem in and of
137 ;; itself, since it makes it too easy for cases of
138 ;; using the cross-compilation host Lisp's CL
139 ;; constant values in the target Lisp to slip by. I
140 ;; got backed into this because the cross-compiler
141 ;; translates DEFCONSTANT SB!XC:FOO into DEFCONSTANT
142 ;; CL:FOO. It would be good to unscrew the
143 ;; cross-compilation package hacks so that that
144 ;; translation doesn't happen. Perhaps:
145 ;; * Replace SB-XC with SB-CL. SB-CL exports all the
146 ;; symbols which ANSI requires to be exported from CL.
147 ;; * Make a nickname SB!CL which behaves like SB!XC.
148 ;; * Go through the loaded-on-the-host code making
149 ;; every target definition be in SB-CL. E.g.
150 ;; DEFMACRO-MUNDANELY DEFCONSTANT becomes
151 ;; DEFMACRO-MUNDANELY SB!CL:DEFCONSTANT.
152 ;; * Make IN-TARGET-COMPILATION-MODE do
153 ;; UNUSE-PACKAGE CL and USE-PACKAGE SB-CL in each
154 ;; of the target packages (then undo it on exit).
155 ;; * Make the cross-compiler's implementation of
156 ;; EVAL-WHEN (:COMPILE-TOPLEVEL) do UNCROSS.
157 ;; (This may not require any change.)
158 ;; * Hack GENESIS as necessary so that it outputs
159 ;; SB-CL stuff as COMMON-LISP stuff.
160 ;; * Now the code here can assert that the symbol
161 ;; being defined isn't in the cross-compilation
162 ;; host's CL package.
163 (unless (eql (find-symbol (symbol-name name) :cl) name)
164 ;; KLUDGE: In the cross-compiler, we use the
165 ;; cross-compilation host's DEFCONSTANT macro
166 ;; instead of just (SETF SYMBOL-VALUE), in order to
167 ;; get whatever blessing the cross-compilation host
168 ;; may expect for a global (SETF SYMBOL-VALUE).
169 ;; (CMU CL, at least around 2.4.19, generated full
170 ;; WARNINGs for code -- e.g. DEFTYPE expanders --
171 ;; which referred to symbols which had been set by
172 ;; (SETF SYMBOL-VALUE). I doubt such warnings are
173 ;; ANSI-compliant, but I'm not sure, so I've
174 ;; written this in a way that CMU CL will tolerate
175 ;; and which ought to work elsewhere too.) -- WHN
177 (eval `(defconstant ,name ',value))))
179 (setf (info :variable :kind name) :constant
180 (info :variable :constant-value name) value)
183 ;;;; DEFINE-COMPILER-MACRO
185 ;;; FIXME: The logic here for handling compiler macros named (SETF
186 ;;; FOO) was added after the fork from SBCL, is not well tested, and
187 ;;; may conflict with subtleties of the ANSI standard. E.g. section
188 ;;; "3.2.2.1 Compiler Macros" says that creating a lexical binding for
189 ;;; a function name shadows a compiler macro, and it's not clear that
190 ;;; that works with this version. It should be tested.
191 (defmacro-mundanely define-compiler-macro (name lambda-list &body body)
193 "Define a compiler-macro for NAME."
194 (let ((whole (gensym "WHOLE-"))
195 (environment (gensym "ENV-")))
196 (multiple-value-bind (body local-decs doc)
197 (parse-defmacro lambda-list whole body name 'define-compiler-macro
198 :environment environment)
199 (let ((def `(lambda (,whole ,environment)
201 (block ,(fun-name-block-name name)
203 `(sb!c::%define-compiler-macro ',name #',def ',lambda-list ,doc)))))
204 (defun sb!c::%define-compiler-macro (name definition lambda-list doc)
205 (declare (ignore lambda-list))
206 (sb!c::%%define-compiler-macro name definition doc))
207 (defun sb!c::%%define-compiler-macro (name definition doc)
208 (setf (sb!xc:compiler-macro-function name) definition)
209 ;; FIXME: Add support for (SETF FDOCUMENTATION) when object is a list
210 ;; and type is COMPILER-MACRO. (Until then, we have to discard any
211 ;; compiler macro documentation for (SETF FOO).)
213 (setf (fdocumentation name 'compiler-macro) doc))
216 ;;;; CASE, TYPECASE, and friends
218 (eval-when (:compile-toplevel :load-toplevel :execute)
220 ;;; CASE-BODY returns code for all the standard "case" macros. NAME is
221 ;;; the macro name, and KEYFORM is the thing to case on. MULTI-P
222 ;;; indicates whether a branch may fire off a list of keys; otherwise,
223 ;;; a key that is a list is interpreted in some way as a single key.
224 ;;; When MULTI-P, TEST is applied to the value of KEYFORM and each key
225 ;;; for a given branch; otherwise, TEST is applied to the value of
226 ;;; KEYFORM and the entire first element, instead of each part, of the
227 ;;; case branch. When ERRORP, no T or OTHERWISE branch is permitted,
228 ;;; and an ERROR form is generated. When PROCEEDP, it is an error to
229 ;;; omit ERRORP, and the ERROR form generated is executed within a
230 ;;; RESTART-CASE allowing KEYFORM to be set and retested.
231 (defun case-body (name keyform cases multi-p test errorp proceedp needcasesp)
232 (unless (or cases (not needcasesp))
233 (warn "no clauses in ~S" name))
234 (let ((keyform-value (gensym))
238 (unless (list-of-length-at-least-p case 1)
239 (error "~S -- bad clause in ~S" case name))
240 (destructuring-bind (keyoid &rest forms) case
241 (cond ((memq keyoid '(t otherwise))
243 (error 'simple-program-error
245 "No default clause is allowed in ~S: ~S"
246 :format-arguments (list name case))
247 (push `(t nil ,@forms) clauses)))
248 ((and multi-p (listp keyoid))
249 (setf keys (append keyoid keys))
250 (push `((or ,@(mapcar (lambda (key)
251 `(,test ,keyform-value ',key))
258 (push `((,test ,keyform-value ',keyoid)
262 (case-body-aux name keyform keyform-value clauses keys errorp proceedp
263 `(,(if multi-p 'member 'or) ,@keys))))
265 ;;; CASE-BODY-AUX provides the expansion once CASE-BODY has groveled
266 ;;; all the cases. Note: it is not necessary that the resulting code
267 ;;; signal case-failure conditions, but that's what KMP's prototype
268 ;;; code did. We call CASE-BODY-ERROR, because of how closures are
269 ;;; compiled. RESTART-CASE has forms with closures that the compiler
270 ;;; causes to be generated at the top of any function using the case
271 ;;; macros, regardless of whether they are needed.
273 ;;; The CASE-BODY-ERROR function is defined later, when the
274 ;;; RESTART-CASE macro has been defined.
275 (defun case-body-aux (name keyform keyform-value clauses keys
276 errorp proceedp expected-type)
278 (let ((block (gensym))
280 `(let ((,keyform-value ,keyform))
286 (cond ,@(nreverse clauses)
291 ',name ',keyform ,keyform-value
292 ',expected-type ',keys)))
294 `(let ((,keyform-value ,keyform))
295 (declare (ignorable ,keyform-value)) ; e.g. (CASE KEY (T))
299 `((t (error 'case-failure
301 :datum ,keyform-value
302 :expected-type ',expected-type
303 :possibilities ',keys))))))))
306 (defmacro-mundanely case (keyform &body cases)
308 "CASE Keyform {({(Key*) | Key} Form*)}*
309 Evaluates the Forms in the first clause with a Key EQL to the value of
310 Keyform. If a singleton key is T then the clause is a default clause."
311 (case-body 'case keyform cases t 'eql nil nil nil))
313 (defmacro-mundanely ccase (keyform &body cases)
315 "CCASE Keyform {({(Key*) | Key} Form*)}*
316 Evaluates the Forms in the first clause with a Key EQL to the value of
317 Keyform. If none of the keys matches then a correctable error is
319 (case-body 'ccase keyform cases t 'eql t t t))
321 (defmacro-mundanely ecase (keyform &body cases)
323 "ECASE Keyform {({(Key*) | Key} Form*)}*
324 Evaluates the Forms in the first clause with a Key EQL to the value of
325 Keyform. If none of the keys matches then an error is signalled."
326 (case-body 'ecase keyform cases t 'eql t nil t))
328 (defmacro-mundanely typecase (keyform &body cases)
330 "TYPECASE Keyform {(Type Form*)}*
331 Evaluates the Forms in the first clause for which TYPEP of Keyform and Type
333 (case-body 'typecase keyform cases nil 'typep nil nil nil))
335 (defmacro-mundanely ctypecase (keyform &body cases)
337 "CTYPECASE Keyform {(Type Form*)}*
338 Evaluates the Forms in the first clause for which TYPEP of Keyform and Type
339 is true. If no form is satisfied then a correctable error is signalled."
340 (case-body 'ctypecase keyform cases nil 'typep t t t))
342 (defmacro-mundanely etypecase (keyform &body cases)
344 "ETYPECASE Keyform {(Type Form*)}*
345 Evaluates the Forms in the first clause for which TYPEP of Keyform and Type
346 is true. If no form is satisfied then an error is signalled."
347 (case-body 'etypecase keyform cases nil 'typep t nil t))
349 ;;;; WITH-FOO i/o-related macros
351 (defmacro-mundanely with-open-stream ((var stream) &body forms-decls)
352 (multiple-value-bind (forms decls) (parse-body forms-decls nil)
353 (let ((abortp (gensym)))
354 `(let ((,var ,stream)
358 (multiple-value-prog1
362 (close ,var :abort ,abortp)))))))
364 (defmacro-mundanely with-open-file ((stream filespec &rest options)
366 `(with-open-stream (,stream (open ,filespec ,@options))
369 (defmacro-mundanely with-input-from-string ((var string &key index start end)
371 (multiple-value-bind (forms decls) (parse-body forms-decls nil)
372 ;; The ONCE-ONLY inhibits compiler note for unreachable code when
374 (once-only ((string string))
377 `(make-string-input-stream ,string ,(or start 0)))
380 (make-string-input-stream ,string
383 (make-string-input-stream ,string
386 `(make-string-input-stream ,string
394 `((setf ,index (string-input-stream-current ,var)))))))))
396 (defmacro-mundanely with-output-to-string ((var &optional string)
398 (multiple-value-bind (forms decls) (parse-body forms-decls nil)
400 `(let ((,var (make-fill-pointer-output-stream ,string)))
405 `(let ((,var (make-string-output-stream)))
410 (get-output-stream-string ,var)))))
412 ;;;; miscellaneous macros
414 (defmacro-mundanely nth-value (n form)
416 "Evaluate FORM and return the Nth value (zero based). This involves no
417 consing when N is a trivial constant integer."
419 (let ((dummy-list nil)
420 (keeper (gensym "KEEPER-")))
421 ;; We build DUMMY-LIST, a list of variables to bind to useless
422 ;; values, then we explicitly IGNORE those bindings and return
423 ;; KEEPER, the only thing we're really interested in right now.
425 (push (gensym "IGNORE-") dummy-list))
426 `(multiple-value-bind (,@dummy-list ,keeper) ,form
427 (declare (ignore ,@dummy-list))
430 `(case (the fixnum ,n)
431 (0 (nth-value 0 ,form))
432 (1 (nth-value 1 ,form))
433 (2 (nth-value 2 ,form))
434 (t (nth (the fixnum ,n) (multiple-value-list ,form)))))))
436 (defmacro-mundanely declaim (&rest specs)
438 "DECLAIM Declaration*
439 Do a declaration or declarations for the global environment."
440 `(eval-when (:compile-toplevel :load-toplevel :execute)
441 ,@(mapcar (lambda (spec) `(sb!xc:proclaim ',spec))
444 (defmacro-mundanely print-unreadable-object ((object stream &key type identity)
446 "Output OBJECT to STREAM with \"#<\" prefix, \">\" suffix, optionally
447 with object-type prefix and object-identity suffix, and executing the
448 code in BODY to provide possible further output."
449 `(%print-unreadable-object ,object ,stream ,type ,identity
454 (defmacro-mundanely ignore-errors (&rest forms)
456 "Execute FORMS handling ERROR conditions, returning the result of the last
457 form, or (VALUES NIL the-ERROR-that-was-caught) if an ERROR was handled."
458 `(handler-case (progn ,@forms)
459 (error (condition) (values nil condition))))