X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcode%2Fhash-table.lisp;h=c352a17a7f819b4df7819988b70b97130d0fbbcb;hb=2db3b6b4cb740d5b6512459c223859f747807b09;hp=f4cc5b83fce1081d04bbfd7379aa881b3a950722;hpb=77360ee4a1f94c41b807be7ad0e8687199fceef1;p=sbcl.git

diff --git a/src/code/hash-table.lisp b/src/code/hash-table.lisp
index f4cc5b8..c352a17 100644
--- a/src/code/hash-table.lisp
+++ b/src/code/hash-table.lisp
@@ -12,63 +12,33 @@
 
 (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.
-  (test (required-argument) :type symbol :read-only t)
+  (test (missing-arg) :type symbol :read-only t)
   ;; 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)
+  (test-fun (missing-arg) :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.
-  (hash-fun (required-argument) :type function :read-only t)
+  (hash-fun (missing-arg) :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 multiply
   ;; it by that.
-  (rehash-size (required-argument) :type (or index (single-float (1.0)))
+  (rehash-size (missing-arg) :type (or index (single-float (1.0)))
 	       :read-only t)
   ;; 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)
+  (rehash-threshold (missing-arg) :type (single-float (0.0) 1.0) :read-only t)
   ;; 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)
+  (rehash-trigger (missing-arg) :type index)
   ;; The current number of entries in the table.
   (number-entries 0 :type index)
   ;; The Key-Value pair vector.
-  (table (required-argument) :type simple-vector)
+  (table (missing-arg) :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
@@ -83,17 +53,16 @@
   (next-free-kv 0 :type index)
   ;; The index vector. This may be larger than the hash size to help
   ;; reduce collisions.
-  (index-vector (required-argument)
-		:type (simple-array (unsigned-byte 32) (*)))
+  (index-vector (missing-arg) :type (simple-array (unsigned-byte 32) (*)))
   ;; This table parallels the KV vector, and is used to chain together
   ;; the hash buckets, the free list, and the values needing rehash, a
   ;; slot will only ever be in one of these lists.
-  (next-vector (required-argument) :type (simple-array (unsigned-byte 32) (*)))
+  (next-vector (missing-arg) :type (simple-array (unsigned-byte 32) (*)))
   ;; This table parallels the KV table, and can be used to store the
   ;; 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 +89,8 @@
 			 (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)))