Ruby 1.9 and NumericalString comparisons in case statements

#127

One of the unit tests that is failing with the transition to Ruby 1.9 is the NumericalString test for case statements. One of the original promises that NumericalString made is the ability to match case statements like this:

x = NumericalString.new("0123")
case x
when 123 then puts "The NumericalString is like a Fixnum"
end

case x
when "0123" then puts "This works for Strings too"
end

However this breaks with Ruby 1.9. The problem is that comparisons are now done with a call to Object#hash, and there is no way for us to know whether to return the hash of a String or Fixnum. With Ruby 1.8 the === operator was called, and we could (and did) satisfy it.

At the moment I do not see a workaround. The "answer" may be to document that you can not use Fixnum case statements with NumericalString. More research is necessary.

See: spec/voip/test_numerical_string.rb:8

Reported by Ben Klang · January 16th, 2011 @ 02:17 PM

Activity

Ben Klang
- State changed from open to fixcommitted
- Milestone set to 1.0.1
- Milestone order changed from 3034 to 0
for Ruby 1.9 users: The behavior of Ruby 1.9 and case statements has changed in a way that renders NumericalString objects incompatible with case statements. The suggested workaround is to cast the NumericalString to a string and then compare.
Example:
```
obj = NumericalString.new("0987")
case obj.to_s
when "0987" then true
else false
end
```
Or, if you need to ignore the leading zero:
```
case obj.to_i
when 987 then true
else false
end
```
February 22nd, 2011 @ 03:54 PM
Ben Klang
- Tag set to backward_incompatible, ruby19
February 22nd, 2011 @ 03:55 PM
Ben Klang
- State changed from fixcommitted to resolved
March 4th, 2011 @ 11:07 AM

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