From: "Haase, Konstantin" <Konstantin.Haase@...>
Date: 2011-10-26T03:56:02+09:00
Subject: [ruby-core:40368] Re: [ruby-trunk - Feature #5479] import StringIO into core, add String#to_io

Maybe another idea would be to introduce a Streamable protocol/class/module, and add a to_stream method both to IO and StringIO. It could also ease implementing your own IO-like behavior.

Konstantin

On Oct 25, 2011, at 11:35 , Aaron Patterson wrote:

> 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 protocol can actually be used. This is the only reason why I proposed moving StringIO 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'
> => true
> irb(main):002:0> File.exist? 'hello!'
> => false
> irb(main):003:0> class String; def to_io; StringIO.new self; end end
> => 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> 
> 
> 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?
> 
> -- 
> Aaron Patterson
> http://tenderlovemaking.com/