Algorithm::Dependency 1.102

Algorithm::Dependency is a base class for implementing various dependency trees.

SYNOPSIS

use Algorithm::Dependency;
use Algorithm::Dependency::Source::File;

# Load the data from a simple text file
my $data_source = Algorithm::Dependency::Source::File->new( foo.txt );

# Create the dependency object, and indicate the items that are already
# selected/installed/etc in the database
my $dep = Algorithm::Dependency->new(
source => $data_source,
selected => [ This, That ]
) or die Failed to set up dependency algorithm;

# For the item Foo, find out the other things we also have to select.
# This WONT include the item we selected, Foo.
my $also = $dep->depends( Foo );
print $also
? "By selecting Foo, you are also selecting the following items: "
. join( , , @$also )
: "Nothing else to select for Foo";

# Find out the order we need to act on the items in.
# This WILL include the item we selected, Foo.
my $schedule = $dep->schedule( Foo );

Algorithm::Dependency is a framework for creating simple read-only dependency heirachies, where you have a set of items that rely on other items in the set, and require actions on them as well.

Despite the most visible of these being software installation systems like the CPAN installer, or debian apt-get, they are usefull in other situations. This module intentionally uses implementation-neutral words, to avoid confusion.