From 4f018492d347839a0ae146c051821c11f4f54912 Mon Sep 17 00:00:00 2001
From: knu <knu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Mon, 16 Nov 2015 07:29:37 +0000
Subject: [PATCH] * lib/set.rb (Hash#flatten!, #add?, #delete?, #collect!,
 #reject!,   #select!, #^, #classify): Micro-optimize some methods for  
 performance and readability.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52591 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 ChangeLog  |  6 ++++++
 lib/set.rb | 31 ++++++++-----------------------
 2 files changed, 14 insertions(+), 23 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 2807acdad0..81e4774d5c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Mon Nov 16 16:28:30 2015  Akinori MUSHA  <knu@iDaemons.org>
+
+	* lib/set.rb (Hash#flatten!, #add?, #delete?, #collect!, #reject!,
+	  #select!, #^, #classify): Micro-optimize some methods for
+	  performance and readability.
+
 Mon Nov 16 16:17:58 2015  SHIBATA Hiroshi  <hsbt@ruby-lang.org>
 
 	* ChangeLog: fixed accidentally commit.
diff --git a/lib/set.rb b/lib/set.rb
index 17775b07ea..9908aa6458 100644
--- a/lib/set.rb
+++ b/lib/set.rb
@@ -200,11 +200,7 @@ class Set
   # Equivalent to Set#flatten, but replaces the receiver with the
   # result in place.  Returns nil if no modifications were made.
   def flatten!
-    if detect { |e| e.is_a?(Set) }
-      replace(flatten())
-    else
-      nil
-    end
+    replace(flatten()) if any? { |e| e.is_a?(Set) }
   end
 
   # Returns true if the set contains the given object.
@@ -320,11 +316,7 @@ class Set
   # Adds the given object to the set and returns self.  If the
   # object is already in the set, returns nil.
   def add?(o)
-    if include?(o)
-      nil
-    else
-      add(o)
-    end
+    add(o) unless include?(o)
   end
 
   # Deletes the given object from the set and returns self.  Use +subtract+ to
@@ -337,11 +329,7 @@ class Set
   # Deletes the given object from the set and returns self.  If the
   # object is not in the set, returns nil.
   def delete?(o)
-    if include?(o)
-      delete(o)
-    else
-      nil
-    end
+    delete(o) if include?(o)
   end
 
   # Deletes every element of the set for which block evaluates to
@@ -367,9 +355,7 @@ class Set
   # Replaces the elements with ones returned by collect().
   def collect!
     block_given? or return enum_for(__method__)
-    set = self.class.new
-    each { |o| set << yield(o) }
-    replace(set)
+    replace(self.class.new(self) { |o| yield(o) })
   end
   alias map! collect!
 
@@ -379,7 +365,7 @@ class Set
     block or return enum_for(__method__)
     n = size
     delete_if(&block)
-    size == n ? nil : self
+    self if size != n
   end
 
   # Equivalent to Set#keep_if, but returns nil if no changes were
@@ -388,7 +374,7 @@ class Set
     block or return enum_for(__method__)
     n = size
     keep_if(&block)
-    size == n ? nil : self
+    self if size != n
   end
 
   # Merges the elements of the given enumerable object to the set and
@@ -439,7 +425,7 @@ class Set
   # ((set | enum) - (set & enum)).
   def ^(enum)
     n = Set.new(enum)
-    each { |o| if n.include?(o) then n.delete(o) else n.add(o) end }
+    each { |o| n.add(o) unless n.delete?(o) }
     n
   end
 
@@ -485,8 +471,7 @@ class Set
     h = {}
 
     each { |i|
-      x = yield(i)
-      (h[x] ||= self.class.new).add(i)
+      (h[yield(i)] ||= self.class.new).add(i)
     }
 
     h