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Feature #15813
closedProposal: Add exception support in `Range#first`
Status:
Closed
Assignee:
-
Target version:
-
Description
Current status¶
Calling Range#last
in endless range((1..)
) raises an exception.
# OK
p (1..Float::INFINITY).end # => Infinity
p (1..).end # => nil
p (1..Float::INFINITY).last # => Infinity
# NG: Raise error: in `last': cannot get the last element of endless range (RangeError)
p (1..).last
p (1..).last(1)
But, calling Range#first
in beginless range((..1)
) does not raise an exception.
# OK
p (-Float::INFINITY..1).begin # => -Infinity
p (..1).begin # => nil
p (-Float::INFINITY..1).first # => -Infinity
# OK: Does not raise
p (..1).first # => nil
# NG: Raise error: in `each': can't iterate from NilClass (TypeError)
p (..1).first(1)
I think the current situation is not consistent, so it is necessary to move the behavior to one side or the other.
Also, in the case of Range#last
, an exception is explicitly raised.
see: https://github.com/ruby/ruby/blob/6a3165e19dfa21babfb2ef1f1c20c9930410b0ec/range.c#L1100-L1102
Proposal¶
Added support to raise an exception for Range#first
too.
Before¶
# OK
p (-Float::INFINITY..10).begin # => -Infinity
p (..10).begin # => nil
p (-Float::INFINITY..10).first # => -Infinity
p (..10).first # => nil
p Range.new(nil, 10).first # => nil
# NG: Raise error: in `each': can't iterate from NilClass (TypeError)
p (..10).first(1)
After¶
# OK
p (-Float::INFINITY..10).begin # => -Infinity
p (..10).begin # => nil
p (-Float::INFINITY..10).first # => -Infinity
# NG: Raise error: in `first': cannot get the first element of beginless range (RangeError)
p (..10).first
p Range.new(nil, 10).first
p (..10).first(1)
# in Ruby 2.6.1
p Range.new(nil, 10).first
# Error: in `initialize': bad value for range (ArgumentError)
Thank you.
pull request : https://github.com/ruby/ruby/pull/2163
Updated by mame (Yusuke Endoh) over 5 years ago
Merged at 4e88e8692844a2a317bc19481f0f2601b6f00955. Thank you.
Updated by mame (Yusuke Endoh) over 5 years ago
- Status changed from Open to Closed
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