;;;; provided with absolutely no warranty. See the COPYING and CREDITS
;;;; files for more information.
-(in-package "SB!INT")
+(in-package "SB!IMPL")
+\f
+;;;; target constants which need to appear as early as possible
+
+;;; an internal tag for marking empty slots, which needs to be defined
+;;; as early as possible because it appears in macroexpansions for
+;;; iteration over hash tables
+;;;
+;;; CMU CL 18b used :EMPTY for this purpose, which was somewhat nasty
+;;; since it's easily accessible to the user, so that e.g.
+;;; (DEFVAR *HT* (MAKE-HASH-TABLE))
+;;; (SETF (GETHASH :EMPTY *HT*) :EMPTY)
+;;; (MAPHASH (LAMBDA (K V) (FORMAT T "~&~S ~S~%" K V)))
+;;; gives no output -- oops!
+;;;
+;;; FIXME: It'd probably be good to use the unbound marker for this.
+;;; However, there might be some gotchas involving assumptions by
+;;; e.g. AREF that they're not going to return the unbound marker,
+;;; and there's also the noted-below problem that the C-level code
+;;; contains implicit assumptions about this marker.
+;;;
+;;; KLUDGE: Note that as of version 0.pre7 there's a dependence in the
+;;; gencgc.c code on this value being a symbol. (This is only one of
+;;; several nasty dependencies between that code and this, alas.)
+;;; -- WHN 2001-08-17
+(eval-when (:compile-toplevel :load-toplevel :execute)
+ (def!constant +empty-ht-slot+ '%empty-ht-slot%))
+;;; We shouldn't need this mess now that EVAL-WHEN works.
+;;; KLUDGE: Using a private symbol still leaves us vulnerable to users
+;;; getting nonconforming behavior by messing around with
+;;; DO-ALL-SYMBOLS. That seems like a fairly obscure problem, so for
+;;; now we just don't worry about it. If for some reason it becomes
+;;; worrisome and the magic value needs replacement:
+;;; * The replacement value needs to be LOADable with EQL preserved,
+;;; so that the macroexpansion for WITH-HASH-TABLE-ITERATOR will
+;;; work when compiled into a file and loaded back into SBCL.
+;;; (Thus, just uninterning %EMPTY-HT-SLOT% doesn't work.)
+;;; * The replacement value needs to be acceptable to the
+;;; low-level gencgc.lisp hash table scavenging code.
+;;; * The change will break binary compatibility, since comparisons
+;;; against the value used at the time of compilation are wired
+;;; into FASL files.
+;;; -- WHN 20000622
\f
;;;; DO-related stuff which needs to be visible on the cross-compilation host
-(eval-when (:compile-toplevel :load-toplevel :execute)
- (defun do-do-body (varlist endlist decls-and-code bind step name block)
+(eval-when (#-sb-xc :compile-toplevel :load-toplevel :execute)
+ (defun frob-do-body (varlist endlist decls-and-code bind step name block)
(let* ((r-inits nil) ; accumulator for reversed list
(r-steps nil) ; accumulator for reversed list
(label-1 (gensym))
(label-2 (gensym)))
;; Check for illegal old-style DO.
(when (or (not (listp varlist)) (atom endlist))
- (error "Ill-formed ~S -- possibly illegal old style DO?" name))
+ (error "ill-formed ~S -- possibly illegal old style DO?" name))
;; Parse VARLIST to get R-INITS and R-STEPS.
(dolist (v varlist)
- (flet (;; (We avoid using CL:PUSH here so that CL:PUSH can be defined
- ;; in terms of CL:SETF, and CL:SETF can be defined in terms of
- ;; CL:DO, and CL:DO can be defined in terms of the current
- ;; function.)
+ (flet (;; (We avoid using CL:PUSH here so that CL:PUSH can be
+ ;; defined in terms of CL:SETF, and CL:SETF can be
+ ;; defined in terms of CL:DO, and CL:DO can be defined
+ ;; in terms of the current function.)
(push-on-r-inits (x)
(setq r-inits (cons x r-inits)))
;; common error-handling
name
(first v)))
(let ((lv (length v)))
- ;; (We avoid using CL:CASE here so that CL:CASE can be
- ;; defined in terms of CL:SETF, and CL:SETF can be defined
- ;; in terms of CL:DO, and CL:DO can be defined in terms of
- ;; the current function.)
+ ;; (We avoid using CL:CASE here so that CL:CASE can
+ ;; be defined in terms of CL:SETF, and CL:SETF can
+ ;; be defined in terms of CL:DO, and CL:DO can be
+ ;; defined in terms of the current function.)
(cond ((= lv 1)
(push-on-r-inits (first v)))
((= lv 2)
(unless ,(first endlist) (go ,label-1))
(return-from ,block (progn ,@(rest endlist))))))))))
+;;; This is like DO, except it has no implicit NIL block. Each VAR is
+;;; initialized in parallel to the value of the specified INIT form.
+;;; On subsequent iterations, the VARS are assigned the value of the
+;;; STEP form (if any) in parallel. The TEST is evaluated before each
+;;; evaluation of the body FORMS. When the TEST is true, the
+;;; EXIT-FORMS are evaluated as a PROGN, with the result being the
+;;; value of the DO.
(defmacro do-anonymous (varlist endlist &rest body)
- #!+sb-doc
- "DO-ANONYMOUS ({(Var [Init] [Step])}*) (Test Exit-Form*) Declaration* Form*
- Like DO, but has no implicit NIL block. Each Var is initialized in parallel
- to the value of the specified Init form. On subsequent iterations, the Vars
- are assigned the value of the Step form (if any) in parallel. The Test is
- evaluated before each evaluation of the body Forms. When the Test is true,
- the Exit-Forms are evaluated as a PROGN, with the result being the value
- of the DO."
- (do-do-body varlist endlist body 'let 'psetq 'do-anonymous (gensym)))
+ (frob-do-body varlist endlist body 'let 'psetq 'do-anonymous (gensym)))
+\f
+;;;; GENSYM tricks
+
+;;; Automate an idiom often found in macros:
+;;; (LET ((FOO (GENSYM "FOO"))
+;;; (MAX-INDEX (GENSYM "MAX-INDEX-")))
+;;; ...)
+;;;
+;;; "Good notation eliminates thought." -- Eric Siggia
+;;;
+;;; Incidentally, this is essentially the same operator which
+;;; _On Lisp_ calls WITH-GENSYMS.
+(defmacro with-unique-names (symbols &body body)
+ `(let ,(mapcar (lambda (symbol)
+ (let* ((symbol-name (symbol-name symbol))
+ (stem (if (every #'alpha-char-p symbol-name)
+ symbol-name
+ (concatenate 'string symbol-name "-"))))
+ `(,symbol (gensym ,stem))))
+ symbols)
+ ,@body))
+
+;;; Return a list of N gensyms. (This is a common suboperation in
+;;; macros and other code-manipulating code.)
+(declaim (ftype (function (index) list) make-gensym-list))
+(defun make-gensym-list (n)
+ (loop repeat n collect (gensym)))
\f
;;;; miscellany
+;;; Lots of code wants to get to the KEYWORD package or the
+;;; COMMON-LISP package without a lot of fuss, so we cache them in
+;;; variables. TO DO: How much does this actually buy us? It sounds
+;;; sensible, but I don't know for sure that it saves space or time..
+;;; -- WHN 19990521
+;;;
+;;; (The initialization forms here only matter on the cross-compilation
+;;; host; In the target SBCL, these variables are set in cold init.)
+(declaim (type package *cl-package* *keyword-package*))
+(defvar *cl-package* (find-package "COMMON-LISP"))
+(defvar *keyword-package* (find-package "KEYWORD"))
+
;;; Concatenate together the names of some strings and symbols,
;;; producing a symbol in the current package.
-(defun symbolicate (&rest things)
- (values (intern (apply #'concatenate
- 'string
- (mapcar #'string things)))))
+(eval-when (#-sb-xc :compile-toplevel :load-toplevel :execute)
+ (defun symbolicate (&rest things)
+ (let ((name (case (length things)
+ ;; why isn't this just the value in the T branch?
+ ;; Well, this is called early in cold-init, before
+ ;; the type system is set up; however, now that we
+ ;; check for bad lengths, the type system is needed
+ ;; for calls to CONCATENATE. So we need to make sure
+ ;; that the calls are transformed away:
+ (1 (concatenate 'string
+ (the simple-base-string (string (car things)))))
+ (2 (concatenate 'string
+ (the simple-base-string (string (car things)))
+ (the simple-base-string (string (cadr things)))))
+ (3 (concatenate 'string
+ (the simple-base-string (string (car things)))
+ (the simple-base-string (string (cadr things)))
+ (the simple-base-string (string (caddr things)))))
+ (t (apply #'concatenate 'string (mapcar #'string things))))))
+ (values (intern name)))))
;;; like SYMBOLICATE, but producing keywords
(defun keywordicate (&rest things)
(let ((*package* *keyword-package*))
(apply #'symbolicate things)))
+;;; Access *PACKAGE* in a way which lets us recover when someone has
+;;; done something silly like (SETF *PACKAGE* :CL-USER). (Such an
+;;; assignment is undefined behavior, so it's sort of reasonable for
+;;; it to cause the system to go totally insane afterwards, but it's a
+;;; fairly easy mistake to make, so let's try to recover gracefully
+;;; instead.)
+(defun sane-package ()
+ (let ((maybe-package *package*))
+ (cond ((and (packagep maybe-package)
+ ;; For good measure, we also catch the problem of
+ ;; *PACKAGE* being bound to a deleted package.
+ ;; Technically, this is not undefined behavior in itself,
+ ;; but it will immediately lead to undefined to behavior,
+ ;; since almost any operation on a deleted package is
+ ;; undefined.
+ (package-name maybe-package))
+ maybe-package)
+ (t
+ ;; We're in the undefined behavior zone. First, munge the
+ ;; system back into a defined state.
+ (let ((really-package (find-package :cl-user)))
+ (setf *package* really-package)
+ ;; Then complain.
+ (error 'simple-type-error
+ :datum maybe-package
+ :expected-type '(and package (satisfies package-name))
+ :format-control
+ "~@<~S can't be a ~A: ~2I~_~S has been reset to ~S.~:>"
+ :format-arguments (list '*package*
+ (if (packagep maybe-package)
+ "deleted package"
+ (type-of maybe-package))
+ '*package* really-package)))))))
+
+;;; Access *DEFAULT-PATHNAME-DEFAULTS*, issuing a warning if its value
+;;; is silly. (Unlike the vaguely-analogous SANE-PACKAGE, we don't
+;;; actually need to reset the variable when it's silly, since even
+;;; crazy values of *DEFAULT-PATHNAME-DEFAULTS* don't leave the system
+;;; in a state where it's hard to recover interactively.)
+(defun sane-default-pathname-defaults ()
+ (let* ((dfd *default-pathname-defaults*)
+ (dfd-dir (pathname-directory dfd)))
+ ;; It's generally not good to use a relative pathname for
+ ;; *DEFAULT-PATHNAME-DEFAULTS*, since relative pathnames
+ ;; are defined by merging into a default pathname (which is,
+ ;; by default, *DEFAULT-PATHNAME-DEFAULTS*).
+ (when (and (consp dfd-dir)
+ (eql (first dfd-dir) :relative))
+ (warn
+ "~@<~S is a relative pathname. (But we'll try using it anyway.)~@:>"
+ '*default-pathname-defaults*))
+ dfd))
+
;;; Give names to elements of a numeric sequence.
(defmacro defenum ((&key (prefix "") (suffix "") (start 0) (step 1))
&rest identifiers)
(if (consp id)
(values (car id) (cdr id))
(values id nil))
- ;; (This could be SYMBOLICATE, except that due to
- ;; bogobootstrapping issues SYMBOLICATE isn't defined yet.)
- (push `(defconstant ,(symbolicate prefix root suffix)
+ (push `(def!constant ,(symbolicate prefix root suffix)
,(+ start (* step index))
,@docs)
results)))
;;; structure for each object file which contains code referring to
;;; the value, plus perhaps one more copy bound to the SYMBOL-VALUE of
;;; the constant. If you don't want that to happen, you should
-;;; probably use DEFPARAMETER instead.
+;;; probably use DEFPARAMETER instead; or if you truly desperately
+;;; need to avoid runtime indirection through a symbol, you might be
+;;; able to do something with LOAD-TIME-VALUE or MAKE-LOAD-FORM.
(defmacro defconstant-eqx (symbol expr eqx &optional doc)
- (let ((expr-tmp (gensym "EXPR-TMP-")))
- `(progn
- ;; When we're building the cross-compiler, and in most
- ;; situations even when we're running the cross-compiler,
- ;; all we need is a nice portable definition in terms of the
- ;; ANSI Common Lisp operations.
- (eval-when (:compile-toplevel :load-toplevel :execute)
- (let ((,expr-tmp ,expr))
- (unless (and (boundp ',symbol)
- (constantp ',symbol)
- (funcall ,eqx (symbol-value ',symbol) ,expr-tmp))
- (defconstant ,symbol ,expr ,@(when doc `(,doc))))))
- ;; The #+SB-XC :COMPILE-TOPLEVEL situation is special, since we
- ;; want to define the symbol not just in the cross-compilation
- ;; host Lisp (which was handled above) but also in the
- ;; cross-compiler (which we will handle now).
- ;;
- ;; KLUDGE: It would probably be possible to do this fairly
- ;; cleanly, in a way parallel to the code above, if we had
- ;; SB!XC:FOO versions of all the primitives CL:FOO used above
- ;; (e.g. SB!XC:BOUNDP, SB!XC:SYMBOL-VALUE, and
- ;; SB!XC:DEFCONSTANT), and took care to call them. But right
- ;; now we just hack around in the guts of the cross-compiler
- ;; instead. -- WHN 2000-11-03
- #+sb-xc
- (eval-when (:compile-toplevel)
- (let ((,expr-tmp ,expr))
- (unless (and (eql (info :variable :kind ',symbol) :constant)
- (funcall ,eqx
- (info :variable :constant-value ',symbol)
- ,expr-tmp))
- (sb!c::%defconstant ',symbol ,expr-tmp ,doc)))))))
+ `(def!constant ,symbol
+ (%defconstant-eqx-value ',symbol ,expr ,eqx)
+ ,@(when doc (list doc))))
+(defun %defconstant-eqx-value (symbol expr eqx)
+ (declare (type function eqx))
+ (flet ((bummer (explanation)
+ (error "~@<bad DEFCONSTANT-EQX ~S ~2I~_~S: ~2I~_~A ~S~:>"
+ symbol
+ expr
+ explanation
+ (symbol-value symbol))))
+ (cond ((not (boundp symbol))
+ expr)
+ ((not (constantp symbol))
+ (bummer "already bound as a non-constant"))
+ ((not (funcall eqx (symbol-value symbol) expr))
+ (bummer "already bound as a different constant value"))
+ (t
+ (symbol-value symbol)))))
+\f
+;;; a helper function for various macros which expect clauses of a
+;;; given length, etc.
+;;;
+;;; Return true if X is a proper list whose length is between MIN and
+;;; MAX (inclusive).
+(defun proper-list-of-length-p (x min &optional (max min))
+ ;; FIXME: This implementation will hang on circular list
+ ;; structure. Since this is an error-checking utility, i.e. its
+ ;; job is to deal with screwed-up input, it'd be good style to fix
+ ;; it so that it can deal with circular list structure.
+ (cond ((minusp max) nil)
+ ((null x) (zerop min))
+ ((consp x)
+ (and (plusp max)
+ (proper-list-of-length-p (cdr x)
+ (if (plusp (1- min))
+ (1- min)
+ 0)
+ (1- max))))
+ (t nil)))
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