From: Robert Dober <robert.dober@...>
Date: 2006-03-29T17:09:06+09:00
Subject: Re: Range#to_a, each - why inconsistent?

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On 3/29/06, vsv <gm.vlkv@gmail.com> wrote:
>
> Could someone explain me, please, why Range with one element is
> iterated inconsistently when this element is empty string:
>
> $ irb --simple-prompt
> >> ('a'..'a').to_a
> =3D> ["a"]
> >> (1..1).to_a
> =3D> [1]
> ## but:
> >> ("".."").to_a
> =3D> []
> >>  ("".."").each{|s| puts 'Inside'}
> =3D> ""..""
> Why to_a returns empty [] and each block never executed?
> Is it bug or feature?
> Any reasonable explanation?
>
> thanks
> Sergey
>
>
>
Sergey
this looks like a bug to me

as far as I recall the definition of a range,
"" is part of the range ("".."")
I verified with irb and
("".."") =3D=3D=3D ""
returns true
"" <=3D> ""  returns 0 as expected,
"".succ =3D> "" which is not quite conclusive for me, but see below
anyway it seems inconsistent that
("".."").to_a.include?("") returns false

while
("".."") =3D=3D=3D "" returns true

No I have mimicked the bahvior with

class NilClass
    def succ; nil; end
    def <=3D>(other); 0; end
end

Guess what
(nil..nil).to_a returns ??

[nil] as expected

the behavior you described clearly seems to be a bug.
Regards
Robert

--
Deux choses sont infinies : l'univers et la b=EAtise humaine ; en ce qui
concerne l'univers, je n'en ai pas acquis la certitude absolue.

- Albert Einstein

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