From: Patrick Doyle <wpdster@...>
Date: 2008-10-08T04:29:18+09:00
Subject: load vs require

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I started looking through the source code for rake and noticed something
curious.

I see that when I execute the "rake" command at the command prompt, I run a
fairly trivial ruby script:

require 'rubygems'

version = ">= 0"

if ARGV.first =~ /^_(.*)_$/ and Gem::Version.correct? $1 then
  version = $1
  ARGV.shift
end

gem 'rake', version
load 'rake'

The #gem method prepended "..../gems/rake-0.8.3/bin" and
".../gems/rake-0.8.3/lib" to my $LOAD_PATH (the "bin" directory first).
Thus, when the script invokes the #load method, it grabs
"..../gems/rake-0.8.3/bin/rake" and starts to execute it.  It looks like
this:

begin
  require 'rake'
rescue LoadError
  require 'rubygems'
  require 'rake'
end
Rake.application.run

Somehow, the "#require" method knows that it should load the "rake.rb" file
from the "lib" directory (the second element in $LOAD_PATH) instead of the
already loaded "rake" from the "bin" directory, (the fist element in
$LOAD_PATH).

Why is that?

--wpd

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