X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcode%2Fhash-table.lisp;h=b82a58580837c11e4a20c2da01b060b25a9beec2;hb=4cf50b1896b25f5337e7c258b0b560da00d47993;hp=76a29780f333656097fabbd8b6dffc84904c5b90;hpb=cea4896b2482b7b2b429c1631d774b4cfbc0efba;p=sbcl.git

diff --git a/src/code/hash-table.lisp b/src/code/hash-table.lisp
index 76a2978..b82a585 100644
--- a/src/code/hash-table.lisp
+++ b/src/code/hash-table.lisp
@@ -12,54 +12,27 @@
 
 (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 part of
-  ;; the exported interface.
+  ;; The type of hash table this is. Only used for printing and as
+  ;; part of the exported interface.
   (test (required-argument) :type symbol :read-only t)
-  ;; The function used to compare two keys. Returns T if they are the same
-  ;; and NIL if not.
+  ;; The function used to compare two keys. Returns T if they are the
+  ;; same and NIL if not.
   (test-fun (required-argument) :type function :read-only t)
-  ;; The function used to compute the hashing of a key. Returns two values:
-  ;; the index hashing and T if that might change with the next GC.
+  ;; The function used to compute the hashing of a key. Returns two
+  ;; values: the index hashing and T if that might change with the
+  ;; next GC.
   (hash-fun (required-argument) :type function :read-only t)
-  ;; How much to grow the hash table by when it fills up. If an index, then
-  ;; add that amount. If a floating point number, then multiple it by that.
+  ;; how much to grow the hash table by when it fills up. If an index,
+  ;; then add that amount. If a floating point number, then multiply
+  ;; it by that.
   (rehash-size (required-argument) :type (or index (single-float (1.0)))
 	       :read-only t)
-  ;; How full the hash table has to get before we rehash.
+  ;; how full the hash table has to get before we rehash
   (rehash-threshold (required-argument) :type (single-float (0.0) 1.0)
 		    :read-only t)
-  ;; The number of entries before a rehash, just the one less than the
+  ;; The number of entries before a rehash, just one less than the
   ;; size of the next-vector, hash-vector, and half the size of the
   ;; kv-vector.
   (rehash-trigger (required-argument) :type index)
@@ -67,9 +40,10 @@
   (number-entries 0 :type index)
   ;; The Key-Value pair vector.
   (table (required-argument) :type simple-vector)
-  ;; True if this is a weak hash table, meaning that key->value mappings will
-  ;; disappear if there are no other references to the key. Note: this only
-  ;; matters if the hash function indicates that the hashing is EQ based.
+  ;; True if this is a weak hash table, meaning that key->value
+  ;; mappings will disappear if there are no other references to the
+  ;; key. Note: this only matters if the hash function indicates that
+  ;; the hashing is EQ based.
   (weak-p nil :type (member t nil))
   ;; Index into the next-vector, chaining together buckets that need
   ;; to be rehashed because their hashing is EQ based and the key has
@@ -90,7 +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)
@@ -117,8 +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)))