enumerator.c: Introduce Enumerator::ArithmeticSequence

This commit introduces new core class Enumerator::ArithmeticSequence.
Enumerator::ArithmeticSequence is a subclass of Enumerator, and
represents a number generator of an arithmetic sequence.

After this commit, Numeric#step and Range#step without blocks
returned an ArithmeticSequence object instead of an Enumerator.

This class introduces the following incompatibilities:

- You can create a zero-step ArithmeticSequence,
  and its size is not ArgumentError, but Infinity.
- You can create a negative-step ArithmeticSequence from a range.

[ruby-core:82816] [Feature #13904]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64205 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 10 insertions, 2 deletions

diff --git a/test/ruby/test_numeric.rb b/test/ruby/test_numeric.rb
index 2026f3b155..e48c3448e8 100644
--- a/test/ruby/test_numeric.rb
+++ b/test/ruby/test_numeric.rb
@@ -260,11 +260,11 @@ class TestNumeric < Test::Unit::TestCase
     assert_raise(ArgumentError) { 1.step(10, 1, 0) { } }
     assert_raise(ArgumentError) { 1.step(10, 1, 0).size }
     assert_raise(ArgumentError) { 1.step(10, 0) { } }
-    assert_raise(ArgumentError) { 1.step(10, 0).size }
     assert_raise(ArgumentError) { 1.step(10, "1") { } }
     assert_raise(ArgumentError) { 1.step(10, "1").size }
     assert_raise(TypeError) { 1.step(10, nil) { } }
-    assert_raise(TypeError) { 1.step(10, nil).size }
+    assert_nothing_raised { 1.step(10, 0).size }
+    assert_nothing_raised { 1.step(10, nil).size }
     assert_nothing_raised { 1.step(by: 0, to: nil) }
     assert_nothing_raised { 1.step(by: 0, to: nil).size }
     assert_nothing_raised { 1.step(by: 0) }
@@ -272,6 +272,14 @@ class TestNumeric < Test::Unit::TestCase
     assert_nothing_raised { 1.step(by: nil) }
     assert_nothing_raised { 1.step(by: nil).size }
 
+    assert_kind_of(Enumerator::ArithmeticSequence, 1.step(10))
+    assert_kind_of(Enumerator::ArithmeticSequence, 1.step(10, 2))
+    assert_kind_of(Enumerator::ArithmeticSequence, 1.step(10, by: 2))
+    assert_kind_of(Enumerator::ArithmeticSequence, 1.step(by: 2))
+    assert_kind_of(Enumerator::ArithmeticSequence, 1.step(by: 2, to: nil))
+    assert_kind_of(Enumerator::ArithmeticSequence, 1.step(by: 2, to: 10))
+    assert_kind_of(Enumerator::ArithmeticSequence, 1.step(by: -1))
+
     bug9811 = '[ruby-dev:48177] [Bug #9811]'
     assert_raise(ArgumentError, bug9811) { 1.step(10, foo: nil) {} }
     assert_raise(ArgumentError, bug9811) { 1.step(10, foo: nil).size }