From: CHubas <CHubas7@...>
Date: 2006-10-21T03:40:19+09:00
Subject: Re: where to put require


Jan Svitok wrote:

> Sometimes (=rarely), when you want to require later or not at all,
> it's useful to put require inside a method.

Just to make it a little clearer, by experimenting you can see:

-------------
def check
  a = ['foo', 'bar', 'baz'] * 2
  begin
    a.each_slice(3) {|slice| p slice}
  rescue Exception
    puts "No such method\n"
  end
  require 'enumerator'
  a.each_slice(3){|slice| p slice}
end

#Test starts here

begin
  x.each_slice(3) {|slice| p slice}
rescue Exception
  puts "No such method\n"
end

puts $".include?('enumerator.so')

check

puts $".include?('enumerator.so')

x = ['foo', 'bar', 'baz'] * 2
x.each_slice(2) {|slice| p slice}
---------------
Produces ->
No such method
false
No such method
["foo", "bar", "baz"]
["foo", "bar", "baz"]
true
["FOO", "BAR"]
["BAZ", "FOO"]
["BAR", "BAZ"]

As you can see, 'require' is itself a method (btw, mixed with the
require method of rubygems/custom_require.rb if specified), that calls
a library and adds it to $". Such library is called the first time is
required. So, as Jan said, you may call it anywhere on your program
depending on where do YOU require it.