From: David Masover <ninja@...>
Date: 2008-08-16T14:18:37+09:00
Subject: More autoload...

No one had anything to say about this... Hmm.

In case you didn't realize: I'm testing all of this in Ruby 1.9.


I thought of a sneakier approach: The rdoc specifies that autoload will call 
Kernel::require:

http://ruby-doc.org/core-1.9/classes/Kernel.html#M006100

And it does, indeed, seem to behave this way -- so long as I don't redefine 
Kernel::require. A simple test:

$ irb1.9
irb(main):001:0> module Kernel
irb(main):002:1> alias_method :require_without_me, :require
irb(main):003:1> def require(*args, &block)
irb(main):004:2> puts 'Require called:'
irb(main):005:2> p args
irb(main):006:2> p block
irb(main):007:2> require_without_me *args, &block
irb(main):008:2> end
irb(main):009:1> end
=> nil
irb(main):010:0> autoload :Foo, 'foo'
=> nil
irb(main):011:0> Foo
loaded foo.rb
=> Foo
irb(main):012:0> require 'foo/bar'
Require called:
["foo/bar"]
nil
loaded bar.rb
=> true
irb(main):013:0>



For what it's worth, both foo.rb and foo/bar.rb have 'puts' statements in 
them, declaring that they were loaded.

Maybe it's irb at fault? Hmm... I created this file:

module Kernel
  alias_method :require_without_me, :require
  def require(*args, &block)
    if args.first == 'test/file/not/loading'
      puts 'Not loading the test file'
    else
      require_without_me(*args, &block)
    end
  end
end

puts 'The following works:'
require 'test/file/not/loading'

puts 'The following does not:'
autoload :Foo, 'test/file/not/loading'
Foo



I'd expect it to end with a constant not found, or module not found.
Instead, I get:

$ ruby1.9 test.rb
The following works:
Not loading the test file
The following does not:
test.rb:17:in `<main>': no such file to load -- test/file/not/loading 
(LoadError)



Doesn't look like I typoed.


So, in other words, autoload is either using its own interpretation of 
require, or it's hardcoding (in C) a call to the original require, rather 
than going through the Ruby code. (I wonder how this would have cooperated 
with Rubygems, had that not been included?)

So far, the crushing limitation of autoload is that I can't easily autoload 
namespace'd things, without littering the namespace itself with autoload 
methods -- or eager-loading all parent namespaces.

Well, that, and I can't seem to customize its behavior _at_all_ other than by 
rewriting it from scratch, making it somewhat useless.