* hash.c: added documentation for Hash about how it uses eql? and

  hash methods for the keys.  [ruby-core:09995]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/matzruby@11554 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Tue Jan 23 10:48:17 2007  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* hash.c: added documentation for Hash about how it uses eql? and
+	  hash methods for the keys.  [ruby-core:09995]
+
 Wed Jan 10 00:10:23 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* array.c (rb_ary_replace): use ptr and len of orig instead of

hash.c

@@ -2370,7 +2370,39 @@ env_update(VALUE env, VALUE hash)
  *  Hashes have a <em>default value</em> that is returned when accessing
  *  keys that do not exist in the hash. By default, that value is
  *  <code>nil</code>.
- *     
+ *  
+ *  <code>Hash</code> uses <code>key.eql?</code> to test keys for equality.
+ *  If you need to use instances of your own classes as keys in a <code>Hash</code>,
+ *  it is recommended that you define both the <code>eql?</code> and <code>hash</code>
+ *  methods. The <code>hash</code> method must have the property that 
+ *  <code>a.eql?(b)</code> implies <code>a.hash == b.hash</code>.
+ *
+ *    class MyClass
+ *      attr_reader :str
+ *      def initialize(str)
+ *        @str = str
+ *      end
+ *      def eql?(o)
+ *        o.is_a?(MyClass) && str == o.str
+ *      end
+ *      def hash
+ *        @str.hash
+ *      end
+ *    end
+ *    
+ *    a = MyClass.new("some string")
+ *    b = MyClass.new("some string")
+ *    a.eql? b  #=> true
+ *    
+ *    h = {}
+ *    
+ *    h[a] = 1
+ *    h[a]      #=> 1
+ *    h[b]      #=> 1
+ *    
+ *    h[b] = 2
+ *    h[a]      #=> 2
+ *    h[b]      #=> 2
  */
 
 void

version.h

@@ -1,15 +1,15 @@
 #define RUBY_VERSION "1.9.0"
-#define RUBY_RELEASE_DATE "2007-01-10"
+#define RUBY_RELEASE_DATE "2007-01-23"
 #define RUBY_VERSION_CODE 190
-#define RUBY_RELEASE_CODE 20070110
+#define RUBY_RELEASE_CODE 20070123
 #define RUBY_PATCHLEVEL 0
 
 #define RUBY_VERSION_MAJOR 1
 #define RUBY_VERSION_MINOR 9
 #define RUBY_VERSION_TEENY 0
 #define RUBY_RELEASE_YEAR 2007
 #define RUBY_RELEASE_MONTH 1
-#define RUBY_RELEASE_DAY 10
+#define RUBY_RELEASE_DAY 23
 
 RUBY_EXTERN const char ruby_version[];
 RUBY_EXTERN const char ruby_release_date[];