From: Eric Hodel <drbrain@...7.net>
Date: 2012-06-14T07:48:50+09:00
Subject: Re: require_relative? why didn't we "relative do"

On Jun 12, 2012, at 20:34, Intransition wrote:
> I wonder if it would been better if we had gone another route with the whole `#require_relative` thing. Instead of a special require method, we could have a method that adds the current file's directory to the top of the $LOAD_PATH temporarily while a block executes.
> 
> For example, lets say we have a library `fruit_basket' with:
> 
>     lib/
>       fruit_basket.rb
>       fruit_basket/
>         grape.rb
>         orange.rb
> 
> Then in `fruit_basket.rb`:
> 
>     relative do
>       require 'grape'
>       require 'orange'
>     end

Say we also have the library "color":

  lib/
    orange.rb

And "flavor":

  lib/
    grape.rb
    banana.rb

Which files are loaded with:

gem 'color'
gem 'flavor'
require 'fruit_basket'

Say we have grafted fruits in fruit_basket such as lib/fruit_basket/lemon-orange.rb:

  # lemon seedling with orange grafted on
  require 'lemon'
  require 'orange'

  # …

Note that this file depends on being loaded from inside fruit_basket.rb's relative block, but that is not explicitly stated:

lib/fruit_basket.rb:
  relative do
    require 'lemon-orange'
    # ...
  end

gem 'color'
gem 'flavor'
require 'fruit_basket'

Which files were loaded?

require_relative doesn't have the problem of the reader of the source needing external information to determine "which directory does this require operate in?" since it is explicit.  I don't see how you make it explicit for require inside a relative block.

Say you have two threads:

gem 'color'
gem 'flavor'

Thread.start do
  require 'orange'
end

Thread.start do
  require 'fruit_basket'
end

Are one or two "orange.rb" files loaded?  Which ones?