From: Kurt Stephens <ks@...>
Date: 2009-11-21T16:32:06+09:00
Subject: [ruby-core:26856] Re: Internals: #to_s .vs. #to_str?

Does "123#{xyz}456" use xyz.to_s or xyz.to_str?

NARUSE, Yui wrote:
> Kurt Stephens wrote:
>> Is there a description of the semantic differences between #to_s and
>> #to_str?  Are there any particular constraints on the results of these
>> methods?  Is it considered "legal" to return frozen Strings in some
>> cases for either of the two?   Is one used internal for implicit casts?
>>
>> I have some ideas that may reduce GC work and improve large String
>> concatenation.
>>
>> I do remember a discussion about the differences between #to_a and
>> #to_ary, but I don't quite remember why they are semantically different.
> 
> to_int, to_str, to_ary, to_hash are fot implicit conversion.
> path.to_str is called in path of following code, if path is not String:
>   open(path){|f| ... }
> 
> to_i, to_s, to_a are explicit conversion.
> 
> David Flanagan's Programing Language Ruby describes
> those type conversion of Ruby at 3.8.7.
>