;;;; 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
;;; 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
-;;;
-;;; FIXME: We end up doing two DEFCONSTANT forms because (1) LispWorks
-;;; needs EVAL-WHEN wrapped around DEFCONSTANT, and (2) SBCL's
-;;; DEFCONSTANT expansion doesn't seem to behave properly inside
-;;; EVAL-WHEN, so that without this, the +EMPTY-HT-SLOT+ references in
-;;; e.g. DOHASH macroexpansions don't end up being replaced by
-;;; constant values, so that the system dies at cold init because
-;;; '+EMPTY-HT-SLOT+ isn't bound yet. It's hard to fix this properly
-;;; until SBCL's EVAL-WHEN is fixed, which is waiting for the IR1
-;;; interpreter to go away, which is waiting for sbcl-0.7.x..
(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.
-#+nil (defconstant +empty-ht-slot+ '#.+empty-ht-slot+) ; egads.. See FIXME above.
+
;;; 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
(defmacro do-anonymous (varlist endlist &rest body)
(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
(%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
(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)))