1 ;;;; various user-level definitions which need to be done particularly
4 ;;;; This software is part of the SBCL system. See the README file for
7 ;;;; This software is derived from the CMU CL system, which was
8 ;;;; written at Carnegie Mellon University and released into the
9 ;;;; public domain. The software is in the public domain and is
10 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
11 ;;;; files for more information.
15 ;;;; target constants which need to appear as early as possible
17 ;;; an internal tag for marking empty slots, which needs to be defined
18 ;;; as early as possible because it appears in macroexpansions for
19 ;;; iteration over hash tables
21 ;;; CMU CL 18b used :EMPTY for this purpose, which was somewhat nasty
22 ;;; since it's easily accessible to the user, so that e.g.
23 ;;; (DEFVAR *HT* (MAKE-HASH-TABLE))
24 ;;; (SETF (GETHASH :EMPTY *HT*) :EMPTY)
25 ;;; (MAPHASH (LAMBDA (K V) (FORMAT T "~&~S ~S~%" K V)))
26 ;;; gives no output -- oops!
28 ;;; FIXME: It'd probably be good to use the unbound marker for this.
29 ;;; However, there might be some gotchas involving assumptions by
30 ;;; e.g. AREF that they're not going to return the unbound marker,
31 ;;; and there's also the noted-below problem that the C-level code
32 ;;; contains implicit assumptions about this marker.
34 ;;; KLUDGE: Note that as of version 0.pre7 there's a dependence in the
35 ;;; gencgc.c code on this value being a symbol. (This is only one of
36 ;;; several nasty dependencies between that code and this, alas.)
39 ;;; FIXME: We end up doing two DEFCONSTANT forms because (1) LispWorks
40 ;;; needs EVAL-WHEN wrapped around DEFCONSTANT, and (2) SBCL's
41 ;;; DEFCONSTANT expansion doesn't seem to behave properly inside
42 ;;; EVAL-WHEN, so that without this, the +EMPTY-HT-SLOT+ references in
43 ;;; e.g. DOHASH macroexpansions don't end up being replaced by
44 ;;; constant values, so that the system dies at cold init because
45 ;;; '+EMPTY-HT-SLOT+ isn't bound yet. It's hard to fix this properly
46 ;;; until SBCL's EVAL-WHEN is fixed, which is waiting for the IR1
47 ;;; interpreter to go away, which is waiting for sbcl-0.7.x..
48 (eval-when (:compile-toplevel :load-toplevel :execute)
49 (defconstant +empty-ht-slot+ '%empty-ht-slot%))
50 ;;; We shouldn't need this mess now that EVAL-WHEN works.
51 #+nil (defconstant +empty-ht-slot+ '#.+empty-ht-slot+) ; egads.. See FIXME above.
52 ;;; KLUDGE: Using a private symbol still leaves us vulnerable to users
53 ;;; getting nonconforming behavior by messing around with
54 ;;; DO-ALL-SYMBOLS. That seems like a fairly obscure problem, so for
55 ;;; now we just don't worry about it. If for some reason it becomes
56 ;;; worrisome and the magic value needs replacement:
57 ;;; * The replacement value needs to be LOADable with EQL preserved,
58 ;;; so that the macroexpansion for WITH-HASH-TABLE-ITERATOR will
59 ;;; work when compiled into a file and loaded back into SBCL.
60 ;;; (Thus, just uninterning %EMPTY-HT-SLOT% doesn't work.)
61 ;;; * The replacement value needs to be acceptable to the
62 ;;; low-level gencgc.lisp hash table scavenging code.
63 ;;; * The change will break binary compatibility, since comparisons
64 ;;; against the value used at the time of compilation are wired
68 ;;;; DO-related stuff which needs to be visible on the cross-compilation host
70 (eval-when (:compile-toplevel :load-toplevel :execute)
71 (defun do-do-body (varlist endlist decls-and-code bind step name block)
72 (let* ((r-inits nil) ; accumulator for reversed list
73 (r-steps nil) ; accumulator for reversed list
76 ;; Check for illegal old-style DO.
77 (when (or (not (listp varlist)) (atom endlist))
78 (error "ill-formed ~S -- possibly illegal old style DO?" name))
79 ;; Parse VARLIST to get R-INITS and R-STEPS.
81 (flet (;; (We avoid using CL:PUSH here so that CL:PUSH can be
82 ;; defined in terms of CL:SETF, and CL:SETF can be
83 ;; defined in terms of CL:DO, and CL:DO can be defined
84 ;; in terms of the current function.)
86 (setq r-inits (cons x r-inits)))
87 ;; common error-handling
89 (error "~S is an illegal form for a ~S varlist." v name)))
90 (cond ((symbolp v) (push-on-r-inits v))
92 (unless (symbolp (first v))
93 (error "~S step variable is not a symbol: ~S"
96 (let ((lv (length v)))
97 ;; (We avoid using CL:CASE here so that CL:CASE can
98 ;; be defined in terms of CL:SETF, and CL:SETF can
99 ;; be defined in terms of CL:DO, and CL:DO can be
100 ;; defined in terms of the current function.)
102 (push-on-r-inits (first v)))
106 (push-on-r-inits (list (first v) (second v)))
107 (setq r-steps (list* (third v) (first v) r-steps)))
108 (t (illegal-varlist)))))
109 (t (illegal-varlist)))))
110 ;; Construct the new form.
111 (multiple-value-bind (code decls) (parse-body decls-and-code nil)
113 (,bind ,(nreverse r-inits)
119 (,step ,@(nreverse r-steps))
121 (unless ,(first endlist) (go ,label-1))
122 (return-from ,block (progn ,@(rest endlist))))))))))
124 ;;; This is like DO, except it has no implicit NIL block. Each VAR is
125 ;;; initialized in parallel to the value of the specified INIT form.
126 ;;; On subsequent iterations, the VARS are assigned the value of the
127 ;;; STEP form (if any) in parallel. The TEST is evaluated before each
128 ;;; evaluation of the body FORMS. When the TEST is true, the
129 ;;; EXIT-FORMS are evaluated as a PROGN, with the result being the
131 (defmacro do-anonymous (varlist endlist &rest body)
132 (do-do-body varlist endlist body 'let 'psetq 'do-anonymous (gensym)))
136 ;;; Concatenate together the names of some strings and symbols,
137 ;;; producing a symbol in the current package.
138 (eval-when (:compile-toplevel :load-toplevel :execute)
139 (defun symbolicate (&rest things)
140 (values (intern (apply #'concatenate
142 (mapcar #'string things))))))
144 ;;; like SYMBOLICATE, but producing keywords
145 (defun keywordicate (&rest things)
146 (let ((*package* *keyword-package*))
147 (apply #'symbolicate things)))
149 ;;; Access *PACKAGE* in a way which lets us recover when someone has
150 ;;; done something silly like (SETF *PACKAGE* :CL-USER). (Such an
151 ;;; assignment is undefined behavior, so it's sort of reasonable for
152 ;;; it to cause the system to go totally insane afterwards, but it's a
153 ;;; fairly easy mistake to make, so let's try to recover gracefully
155 (defun sane-package ()
156 (let ((maybe-package *package*))
157 (cond ((and (packagep maybe-package)
158 ;; For good measure, we also catch the problem of
159 ;; *PACKAGE* being bound to a deleted package.
160 ;; Technically, this is not undefined behavior in itself,
161 ;; but it will immediately lead to undefined to behavior,
162 ;; since almost any operation on a deleted package is
164 (package-name maybe-package))
167 ;; We're in the undefined behavior zone. First, munge the
168 ;; system back into a defined state.
169 (let ((really-package (find-package :cl-user)))
170 (setf *package* really-package)
172 (error 'simple-type-error
174 :expected-type '(and package (satisfies package-name))
176 "~@<~S can't be a ~A: ~2I~_~S has been reset to ~S.~:>"
177 :format-arguments (list '*package*
178 (if (packagep maybe-package)
180 (type-of maybe-package))
181 '*package* really-package)))))))
183 ;;; Access *DEFAULT-PATHNAME-DEFAULTS*, issuing a warning if its value
184 ;;; is silly. (Unlike the vaguely-analogous SANE-PACKAGE, we don't
185 ;;; actually need to reset the variable when it's silly, since even
186 ;;; crazy values of *DEFAULT-PATHNAME-DEFAULTS* don't leave the system
187 ;;; in a state where it's hard to recover interactively.)
188 (defun sane-default-pathname-defaults ()
189 (let* ((dfd *default-pathname-defaults*)
190 (dfd-dir (pathname-directory dfd)))
191 ;; It's generally not good to use a relative pathname for
192 ;; *DEFAULT-PATHNAME-DEFAULTS*, since relative pathnames
193 ;; are defined by merging into a default pathname (which is,
194 ;; by default, *DEFAULT-PATHNAME-DEFAULTS*).
195 (when (and (consp dfd-dir)
196 (eql (first dfd-dir) :relative))
198 "~@<~S is a relative pathname. (But we'll try using it anyway.)~@:>"
199 '*default-pathname-defaults*))
202 ;;; Give names to elements of a numeric sequence.
203 (defmacro defenum ((&key (prefix "") (suffix "") (start 0) (step 1))
209 (dolist (id identifiers)
211 (multiple-value-bind (root docs)
213 (values (car id) (cdr id))
215 (push `(defconstant ,(symbolicate prefix root suffix)
216 ,(+ start (* step index))
221 ,@(nreverse results))))
223 ;;; generalization of DEFCONSTANT to values which are the same not
224 ;;; under EQL but under e.g. EQUAL or EQUALP
226 ;;; DEFCONSTANT-EQX is to be used instead of DEFCONSTANT for values
227 ;;; which are appropriately compared using the function given by the
228 ;;; EQX argument instead of EQL.
230 ;;; Note: Be careful when using this macro, since it's easy to
231 ;;; unintentionally pessimize your code. A good time to use this macro
232 ;;; is when the values defined will be fed into optimization
233 ;;; transforms and never actually appear in the generated code; this
234 ;;; is especially common when defining BYTE expressions. Unintentional
235 ;;; pessimization can result when the values defined by this macro are
236 ;;; actually used in generated code: because of the way that the
237 ;;; dump/load system works, you'll typically get one copy of consed
238 ;;; structure for each object file which contains code referring to
239 ;;; the value, plus perhaps one more copy bound to the SYMBOL-VALUE of
240 ;;; the constant. If you don't want that to happen, you should
241 ;;; probably use DEFPARAMETER instead; or if you truly desperately
242 ;;; need to avoid runtime indirection through a symbol, you might be
243 ;;; able to do something with LOAD-TIME-VALUE or MAKE-LOAD-FORM.
244 (defmacro defconstant-eqx (symbol expr eqx &optional doc)
245 `(defconstant ,symbol
246 (%defconstant-eqx-value ',symbol ,expr ,eqx)
247 ,@(when doc (list doc))))
248 (defun %defconstant-eqx-value (symbol expr eqx)
249 (flet ((bummer (explanation)
250 (error "~@<bad DEFCONSTANT-EQX ~S ~2I~_~S: ~2I~_~A ~S~:>"
254 (symbol-value symbol))))
255 (cond ((not (boundp symbol))
257 ((not (constantp symbol))
258 (bummer "already bound as a non-constant"))
259 ((not (funcall eqx (symbol-value symbol) expr))
260 (bummer "already bound as a different constant value"))
262 (symbol-value symbol)))))