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example_environment.rb

This example demonstrates how to use EnvironmentFactory and the resultant Environment.

00001 #!/usr/bin/env ruby
00002 # vim: set sw=4 sts=4 et tw=80 :
00003 
00004 =begin description
00005 This example demonstrates how to use EnvironmentFactory and the resultant
00006 Environment.
00007 =end
00008 
00009 require 'Paludis'
00010 require 'example_command_line'
00011 
00012 include Paludis
00013 
00014 exit_status = 0
00015 
00016 # We use EnvironmentFactory to construct an environment from the user's
00017 # --environment commandline choice. With an empty string, this uses the
00018 # distribution-defined default environment. With a non-empty string, it
00019 # is split into two parts upon the first colon (if there is no colon,
00020 # the second part is considered empty). The first part is the name of
00021 # the environment class to use (e.g. 'paludis', 'portage') and the
00022 # second part is passed as parameters to be handled by that
00023 # environment's constructor.
00024 env = EnvironmentFactory.instance.create(ExampleCommandLine.instance.environment)
00025 
00026 # A lot of the Environment members aren't very useful to clients. The mask
00027 # related methods are used by PackageID, and shouldn't usually be called
00028 # directly from clients. The system information and mirror functions are mostly
00029 # for use by Repository subclasses. The [] operator is covered in other
00030 # examples. That leaves the package database and sets. The package database has
00031 # its own examples, so we'll start with sets:
00032 
00033 world = env.set('world')
00034 if (world)
00035     # see examples_dep_tree.rb for how to make use of this set
00036     puts "World set exists"
00037 else
00038     puts "No world set defined"
00039 end
00040