{Enumerable,Array,Range}#first, {Array,Range}#last with blockfeature/enumerable-first-with-block

* array.c (rb_ary_first, ary_last): extend Array#{first,last} to accept
  a block. If a block is passed, these methods collects only elements
  for which the block returns a truthy value.
* enum.c: extend Enumerable#first to accept a block.
* range.c: extend Range#{first,last} to accept a block.
* gc.c: avoid using rb_ary_last(), because it may call a block.
* test/ruby/test_array.rb: add test
* test/ruby/test_enum.rb: ditto
* test/ruby/test_range.rb: ditto

1 files changed, 8 insertions, 0 deletions

diff --git a/test/ruby/test_range.rb b/test/ruby/test_range.rb
index 2fc2a2b1d3..733d45b6f4 100644
--- a/test/ruby/test_range.rb
+++ b/test/ruby/test_range.rb
@@ -271,6 +271,10 @@ class TestRange < Test::Unit::TestCase
     assert_equal("a", ("a".."c").first)
     assert_equal("c", ("a".."c").last)
     assert_equal(0, (2..0).last)
+    assert_equal(1, (0..11).first { |i| i.odd? })
+    assert_equal(11, (0..11).last { |i| i.odd? })
+    assert_equal([1, 3], (0..11).first(2) { |i| i.odd? })
+    assert_equal([9, 11], (0..11).last(2) { |i| i.odd? })
 
     assert_equal([0, 1, 2], (0...10).first(3))
     assert_equal([7, 8, 9], (0...10).last(3))
@@ -279,6 +283,10 @@ class TestRange < Test::Unit::TestCase
     assert_equal("a", ("a"..."c").first)
     assert_equal("c", ("a"..."c").last)
     assert_equal(0, (2...0).last)
+    assert_equal(1, (0...11).first { |i| i.odd? })
+    assert_equal(9, (0...11).last { |i| i.odd? })
+    assert_equal([1, 3], (0...11).first(2) { |i| i.odd? })
+    assert_equal([7, 9], (0...11).last(2) { |i| i.odd? })
   end
 
   def test_to_s