marcandre	2010-05-30 22:19:09 +0900 (Sun, 30 May 2010)

  New Revision: 28096

  http://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=rev&revision=28096

  Log:
    * lib/set.rb (keep_if, select!): New methods [ruby-core:29749]

  Modified files:
    trunk/ChangeLog
    trunk/NEWS
    trunk/lib/set.rb

Index: ChangeLog
===================================================================
--- ChangeLog	(revision 28095)
+++ ChangeLog	(revision 28096)
@@ -1,3 +1,7 @@
+Sun May 30 22:18:49 2010  Marc-Andre Lafortune  <ruby-core@m...>
+
+	* lib/set.rb (keep_if, select!): New methods [ruby-core:29749]
+
 Sun May 30 21:51:59 2010  Yusuke Endoh  <mame@t...>
 
 	* test/rake/test_application.rb: update a test because of r28089.
Index: lib/set.rb
===================================================================
--- lib/set.rb	(revision 28095)
+++ lib/set.rb	(revision 28096)
@@ -266,6 +266,14 @@
     self
   end
 
+  # Deletes every element of the set for which block evaluates to
+  # false, and returns self.
+  def keep_if
+    block_given? or return enum_for(__method__)
+    to_a.each { |o| @hash.delete(o) unless yield(o) }
+    self
+  end
+
   # Replaces the elements with ones returned by collect().
   def collect!
     block_given? or return enum_for(__method__)
@@ -284,6 +292,15 @@
     size == n ? nil : self
   end
 
+  # Equivalent to Set#keep_if, but returns nil if no changes were
+  # made.
+  def select!
+    block_given? or return enum_for(__method__)
+    n = size
+    keep_if { |o| yield(o) }
+    size == n ? nil : self
+  end
+
   # Merges the elements of the given enumerable object to the set and
   # returns self.
   def merge(enum)
@@ -563,6 +580,14 @@
 	    self
 	  end
 
+	  def keep_if
+	    block_given? or return enum_for(__method__)
+	    n = @hash.size
+	    super
+	    @keys = nil if @hash.size != n
+	    self
+	  end
+
 	  def merge(enum)
 	    @keys = nil
 	    super
Index: NEWS
===================================================================
--- NEWS	(revision 28095)
+++ NEWS	(revision 28096)
@@ -373,6 +373,11 @@
     * Readline.completion_proc= accepts nil.
       nil means to use default completion proc.
 
+* set
+  * new methods:
+    * Set#keep_if
+    * Set#select!
+
 * time
   * incompatible changes:
     * Time.parse raises ArgumentError when no date information.

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