From: Trans <transfire@...>
Date: 2006-12-20T11:20:05+09:00
Subject: Re: Simple copy of attributes


Gavin Kistner wrote:
> From: Trans [mailto:transfire@gmail.com]
> > Facets has Kernel#set_from:
> >
> >   bidule.set_from(biniou, :foo, :bar, :baz)
>
> Out of curiosity, why put that in Kernel instead of Object?
>
> Actually, what heuristic do people use in general for adding methods to
> Kernel versus putting them in Object? Assuming that my oh-so-pretty flow
> diagram[1] is correct, the end functionality should be equivalent. Is it
> just a matter of semantics as to where they ought to go?
>
> [1] http://phrogz.net/RubyLibs/RubyMethodLookupFlow.png

It is something even experienced ruby programmer's can fail to realize:
Object class has NO methods. ri is somewhat misleading in this regard,
and the functionality equivalency you mention often means it goes
unnoticed. it certainly surprised me when i first discovered it. While
only matz can say exactly why, i think Object is left empty for end
programmers to add their extension methods to --that way they are
easily distinguished from built-in Kernel methods. Hence a lower-level
lib like Facets uses Kernel, while a higher-level app like Basecamp
would use Object --at least that's my take on it.

btw that reminds me -- YAML/Syck is sticking some methods in Object,
that perhaps would be more appropriate in Kernel (?)

  irb(main):002:0> p Object.instance_methods(false)
  []
  => nil
  irb(main):003:0> require 'yaml'
  => true
  irb(main):004:0> p Object.instance_methods(false)
  ["taguri", "taguri=", "to_yaml_properties", "to_yaml",
"to_yaml_style"]

t.