From ea40df71fcd67a1fa16205299ac25c803ab331e2 Mon Sep 17 00:00:00 2001
From: knu <knu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Tue, 3 Jun 2008 04:42:32 +0000
Subject: [PATCH] * lib/set.rb (Set#collect, Set#select): Override Enumerable  
 methods and make them return a set. [ruby-core:17055]   (Set#delete_if,
 Set#collect!, Set#reject!, Set#classify)   (Set#divide, Set#delete_if):
 Return an enumerator if no block is   given.   (Set#classify): Define an
 alias `group_by' to override that of   Enumerable.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@16771 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 ChangeLog  | 10 ++++++++++
 lib/set.rb | 32 +++++++++++++++++++++++++++++---
 2 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 7879f28fdd..5c85a33392 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+Tue Jun  3 13:41:08 2008  Akinori MUSHA  <knu@iDaemons.org>
+
+	* lib/set.rb (Set#collect, Set#select): Override Enumerable
+	  methods and make them return a set. [ruby-core:17055]
+	  (Set#delete_if, Set#collect!, Set#reject!, Set#classify)
+	  (Set#divide, Set#delete_if): Return an enumerator if no block is
+	  given.
+	  (Set#classify): Define an alias `group_by' to override that of
+	  Enumerable.
+
 Tue Jun  3 13:35:40 2008  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* process.c (run_exec_pgroup): C99 ism.
diff --git a/lib/set.rb b/lib/set.rb
index b925f8e586..f73aceabbc 100644
--- a/lib/set.rb
+++ b/lib/set.rb
@@ -250,21 +250,41 @@ class Set
   # Deletes every element of the set for which block evaluates to
   # true, and returns self.
   def delete_if
+    block_given? or return enum_for(__method__)
     @hash.delete_if { |o,| yield(o) }
     self
   end
 
-  # Do collect() destructively.
-  def collect!
+  # Calls the given block once for each element and returns a new set
+  # containing the values returned by the block.
+  def collect
+    block_given? or return enum_for(__method__)
     set = self.class.new
     each { |o| set << yield(o) }
-    replace(set)
+  end
+  alias map collect
+
+  # Replaces the values with ones returned by collect().
+  def collect!
+    block_given? or return enum_for(__method__)
+    replace(collect)
   end
   alias map! collect!
 
+  # Calls the given block once for each element and returns a new set
+  # containing those elements for which the block returns a true
+  # value.
+  def select
+    block_given? or return enum_for(__method__)
+    set = self.class.new
+    each { |o| set << o if yield(o) }
+    set
+  end
+
   # Equivalent to Set#delete_if, but returns nil if no changes were
   # made.
   def reject!
+    block_given? or return enum_for(__method__)
     n = size
     delete_if { |o| yield(o) }
     size == n ? nil : self
@@ -356,6 +376,8 @@ class Set
   #             #     2001=>#<Set: {"c.rb", "d.rb", "e.rb"}>,
   #             #     2002=>#<Set: {"f.rb"}>}
   def classify # :yields: o
+    block_given? or return enum_for(__method__)
+
     h = {}
 
     each { |i|
@@ -365,6 +387,7 @@ class Set
 
     h
   end
+  alias group_by classify
 
   # Divides the set into a set of subsets according to the commonality
   # defined by the given block.
@@ -383,6 +406,8 @@ class Set
   #             #            #<Set: {3, 4}>,
   #             #            #<Set: {6}>}>
   def divide(&func)
+    func or return enum_for(__method__)
+
     if func.arity == 2
       require 'tsort'
 
@@ -501,6 +526,7 @@ class SortedSet < Set
 	  end
 
 	  def delete_if
+            block_given? or return enum_for(__method__)
 	    n = @hash.size
 	    @hash.delete_if { |o,| yield(o) }
 	    @keys = nil if @hash.size != n