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
f15069338d