From: Aaron Patterson <tenderlove@...>
Date: 2011-10-26T03:35:36+09:00
Subject: [ruby-core:40367] Re: [ruby-trunk - Feature #5479] import StringIO into core, add String#to_io


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On Wed, Oct 26, 2011 at 02:22:21AM +0900, Haase, Konstantin wrote:
> My main request was to add String#to_io, as Aaron described, so this prot=
ocol can actually be used. This is the only reason why I proposed moving St=
ringIO to core. We could also add String#to_io as a monkey-patch to String =
in stringio in the stdlib.

I really like this idea, but I'm kind of afraid of the consequences.
StringIO isn't a subclass of IO, and some things in ruby call `to_io`
then check the return type:

irb(main):001:0> require 'stringio'
=3D> true
irb(main):002:0> File.exist? 'hello!'
=3D> false
irb(main):003:0> class String; def to_io; StringIO.new self; end end
=3D> nil
irb(main):004:0> File.exist? 'hello!'
TypeError: can't convert String to IO (String#to_io gives StringIO)
        from (irb):4:in `exist?'
        from (irb):4
        from /Users/aaron/.local/bin/irb:12:in `<main>'
irb(main):005:0>=20

I'm not sure which is best: convert StringIO to subclass IO, or find
these places that call `to_io` and fix them.  Not to mention, how do we
"fix" the above example?  What does `exists?` mean in terms of a
StringIO?

--=20
Aaron Patterson
http://tenderlovemaking.com/

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