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task Move watchr and detroit assembly to task directory. [admin]



The idea of Bezel is to overcome the limitations of using different versions of the same package in the same Ruby process.



It works like this. Let's say I wrote a library called TomsLib. Now I want to use TomsLib in my new fancy app, FancyApp. In my FancyApp namespace I have to create a reference to TomsLib.

 module FancyApp
   TomsLib = lib('tomslib', '1.5')

Now I have access to TomsLib, but it is localized to my application. If Jane comes along and wants to use a different version of TomsLib but also utilizes my FancyApp, she could do so:

 module JanesProgram
   TomsLib  = lib('tomslib', '1.0')
   FancyApp = lib('fancyapp')  # use newest available

How does this work? When you call lib(), Bezel looks for the package in the current Gem paths (and in the future, Roll ledger) then it reads the primary package file (eg. tomslib.rb) from the package and evals it into an anonymous module.

This has a some important effects on how you write your Ruby programs:

  1. Any reference to core/standard libraries must be referenced via '::' prefix (eg. ::Enumerable).

  2. Core extensions are not version isolated. So when possible, avoid them or depend on highly stable standardized bases such as Ruby Facets and ActiveSupport.

  3. Since Bezel is a completely different alternative to Ruby's normal load system, your program will require Bezel be installed by your users. No big deal. In other words, list it into your projects dependencies.

  4. A project's main require file must be the same as the library's name.

Despite these necessary practices for its use, Bezel is highly advantageous to the developers and end-users alike in that it puts an absolute end to the dreaded Dependency Hell.


It may not be possible to test Bezel via Travis CI because of the way the tests change the GEM_HOME. Currently they fail because of this, even though they pass on local development machine. We'll leave this for now in hopes we will get it working at some point: Build Status


Copyright (c) 2009 Thomas Sawyer

Bezel is distributed under the same terms as Ruby 1.9+, namely the BSD 2-clause license.

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