From: "trans.  (T. Onoma)" <transami@...>
Date: 2004-10-25T01:48:42+09:00
Subject: Re: [rcr] String#first / String#last

On Sunday 24 October 2004 12:12 pm, ts wrote:
| >>>>> "t" == trans (T Onoma) <transami@runbox.com> writes:
|
| t> On Sunday 24 October 2004 09:52 am, Simon Strandgaard wrote:
|
| t> |     unless n.kind_of?(Integer)
| t> |       raise TypeError, "#{length.class}#to_int should return Integer"
| t> |     end
|
| t> I don't think this is really needed, since such a bug would be worked
| out else t> where. (That #to_int might be used usefully for something other
| then t> returning an integer is extremely unlikely and thus not worth the
| check).
|
| svg% ruby -e 'class A; def to_int() "a" end end; [1,2].first(A.new)'
| -e:1:in `first': A#to_int should return Integer (TypeError)
|         from -e:1
| svg%

I see --to behave like Array's methods.

Seems like a lot overhead though when one considers this kind of thing is 
going on throughout the system.

I added to my lib, but I did this instead:

    begin
      n = n.to_int.abs
    rescue NoMethodError
      raise TypeError, "cannot convert #{length.class} to positive Integer"
    end

which allowed me to get rid of the negative check too. In the very very very 
unlikely case that a non-integer slips through (a String for instance) one 
still just gets:

  ArgumentError: comparison of Fixnum with String failed

T.