X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcode%2Fhash-table.lisp;h=b82a58580837c11e4a20c2da01b060b25a9beec2;hb=b5703d98da9ebfd688c87e14862ab4e26dc94d14;hp=f4cc5b83fce1081d04bbfd7379aa881b3a950722;hpb=77360ee4a1f94c41b807be7ad0e8687199fceef1;p=sbcl.git diff --git a/src/code/hash-table.lisp b/src/code/hash-table.lisp index f4cc5b8..b82a585 100644 --- a/src/code/hash-table.lisp +++ b/src/code/hash-table.lisp @@ -12,35 +12,6 @@ (in-package "SB!IMPL") -;;; an internal tag for marking empty slots -;;; -;;; 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! -;;; -;;; Note that as of version 0.6.6 there's a dependence in the gencgc.c -;;; code on this value being a symbol. (This is only one of many nasty -;;; dependencies between that code and this, alas.) -(defconstant +empty-ht-slot+ '%empty-ht-slot%) -;;; 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 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 - ;;; HASH-TABLE is implemented as a STRUCTURE-OBJECT. (sb!xc:defstruct (hash-table (:constructor %make-hash-table)) ;; The type of hash table this is. Only used for printing and as @@ -93,7 +64,7 @@ ;; hash associated with the key, saving recalculation. Could be ;; useful for EQL, and EQUAL hash tables. This table is not needed ;; for EQ hash tables, and when present the value of #x8000000 - ;; represents EQ-based hashing on the respective Key. + ;; represents EQ-based hashing on the respective key. (hash-vector nil :type (or null (simple-array (unsigned-byte 32) (*))))) (defmacro-mundanely with-hash-table-iterator ((function hash-table) &body body) @@ -120,8 +91,8 @@ (let ((key (aref kv-vector (* 2 index))) (value (aref kv-vector (1+ (* 2 index))))) (incf index) - (unless (and (eq key '#.+empty-ht-slot+) - (eq value '#.+empty-ht-slot+)) + (unless (and (eq key +empty-ht-slot+) + (eq value +empty-ht-slot+)) (return (values t key value)))))))) #',function)))) (macrolet ((,function () '(funcall ,n-function)))