From 0eadc632c1c377d52965e67a8ef09a80fa54f341 Mon Sep 17 00:00:00 2001
From: akr <akr@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Wed, 26 Nov 2014 10:46:50 +0000
Subject: * lib/tsort.rb: Returns an enumerator if no block is given.  
 [ruby-core:66270] [Feature #10508] Proposed by Andrey Savchenko.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48584 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 ChangeLog          |  5 +++++
 lib/tsort.rb       | 14 ++++++++------
 test/test_tsort.rb | 13 +++++++++++++
 3 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index bbe64dc271..8de1f472c6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Nov 26 19:44:13 2014  Tanaka Akira  <akr@fsij.org>
+
+	* lib/tsort.rb: Returns an enumerator if no block is given.
+	  [ruby-core:66270] [Feature #10508] Proposed by Andrey Savchenko.
+
 Wed Nov 26 17:25:45 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* parse.y (f_label, f_kw, formal_argument_gen): ignore invalid
diff --git a/lib/tsort.rb b/lib/tsort.rb
index cb8f67ef60..c40f9c41b2 100644
--- a/lib/tsort.rb
+++ b/lib/tsort.rb
@@ -171,9 +171,7 @@ module TSort
   #   p TSort.tsort(each_node, each_child) # raises TSort::Cyclic
   #
   def TSort.tsort(each_node, each_child)
-    result = []
-    TSort.tsort_each(each_node, each_child) {|element| result << element}
-    result
+    TSort.tsort_each(each_node, each_child).to_a
   end
 
   # The iterator version of the #tsort method.
@@ -221,6 +219,8 @@ module TSort
   #   #   1
   #
   def TSort.tsort_each(each_node, each_child) # :yields: node
+    return to_enum(__method__, each_node, each_child) unless block_given?
+
     TSort.each_strongly_connected_component(each_node, each_child) {|component|
       if component.size == 1
         yield component.first
@@ -276,9 +276,7 @@ module TSort
   #   #=> [[4], [2, 3], [1]]
   #
   def TSort.strongly_connected_components(each_node, each_child)
-    result = []
-    TSort.each_strongly_connected_component(each_node, each_child) {|component| result << component}
-    result
+    TSort.each_strongly_connected_component(each_node, each_child).to_a
   end
 
   # The iterator version of the #strongly_connected_components method.
@@ -340,6 +338,8 @@ module TSort
   #   #   [1]
   #
   def TSort.each_strongly_connected_component(each_node, each_child) # :yields: nodes
+    return to_enum(__method__, each_node, each_child) unless block_given?
+
     id_map = {}
     stack = []
     each_node.call {|node|
@@ -404,6 +404,8 @@ module TSort
   #   #   [1]
   #
   def TSort.each_strongly_connected_component_from(node, each_child, id_map={}, stack=[]) # :yields: nodes
+    return to_enum(__method__, node, each_child, id_map, stack) unless block_given?
+
     minimum_id = node_id = id_map[node] = id_map.size
     stack_length = stack.length
     stack << node
diff --git a/test/test_tsort.rb b/test/test_tsort.rb
index bd60f696a8..4a13a6e635 100644
--- a/test/test_tsort.rb
+++ b/test/test_tsort.rb
@@ -57,6 +57,9 @@ class TSortTest < Test::Unit::TestCase # :nodoc:
     r = []
     TSort.tsort_each(each_node, each_child) {|n| r << n }
     assert_equal([4, 2, 3, 1], r)
+
+    r = TSort.tsort_each(each_node, each_child).map {|n| n.to_s }
+    assert_equal(['4', '2', '3', '1'], r)
   end
 
   def test_s_strongly_connected_components
@@ -85,6 +88,11 @@ class TSortTest < Test::Unit::TestCase # :nodoc:
       r << scc
     }
     assert_equal([[4], [2, 3], [1]], r)
+
+    r = TSort.each_strongly_connected_component(each_node, each_child).map {|scc|
+      scc.map(&:to_s)
+    }
+    assert_equal([['4'], ['2', '3'], ['1']], r)
   end
 
   def test_s_each_strongly_connected_component_from
@@ -95,6 +103,11 @@ class TSortTest < Test::Unit::TestCase # :nodoc:
       r << scc
     }
     assert_equal([[4], [2, 3], [1]], r)
+
+    r = TSort.each_strongly_connected_component_from(1, each_child).map {|scc|
+      scc.map(&:to_s)
+    }
+    assert_equal([['4'], ['2', '3'], ['1']], r)
   end
 end
 
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