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Meta-0.08
River stage zero No dependents
/ Meta::Pdmt::Graph

NAME

Meta::Pdmt::Graph - data structure that represents a Pdmt graph.

COPYRIGHT

Copyright (C) 2001, 2002 Mark Veltzer; All rights reserved.

LICENSE

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.

DETAILS

        MANIFEST: Graph.pm
        PROJECT: meta
        VERSION: 0.24

SYNOPSIS

        package foo;
        use Meta::Pdmt::Graph qw();

DESCRIPTION

This is the dependency graph object for the Pdmt project. The graph is a graph which represents objects (files, db records or whatever) that need to be maintained up to date one relative to the other.

Each node in the graph needs to implement two methods: uptodate and build.

uptodate is a method which returns whether this object is up to date. build is the method which builds the nodes from other nodes.

both of these method of the node receive the graph that it is a member of.

FUNCTIONS

        BEGIN()
        add_vertex($$)
        build_all($)
        build_nodes($$)
        build_node($$)
        TEST($)

FUNCTION DOCUMENTATION

BEGIN()

Bootstrap method to have accessors to the parent pdmt.

add_vertex($$)

Overriding the default graph vertex additio so we could call handlers to manipulate the graph.

build_all($)

This method will build the entire graph (make sure that all nodes are up to date). The method returns the result of the build.

build_nodes($$)

This method will build a set of nodes passed to it. The method returns the result of the build.

build_node($$)

This is the most important method - the build method. The method returns the result of the build. The method receives a list of nodes to be built.

The method is recursive. The method recursivly builds all ingredients for the node to be built. When returning (i.e. all ingrediants are built) the method checks if the node needs to be updated using the requires_update method. If it does need updating then it activates the nodes "build" method.

If the method receives a graph with cycles then it will go into an endless loop. This needs to be fixed in the future.

This object inherits from a graph object which must give these services for this object to do it's work effectivly: 1. O(1) tag all nodes as unvisited. 2. O(1) check if the graph has cycles (at the expense of more time at each insert of node). The underlying graph may just reject insertion of nodes which create cycles. 3. O(1) retrieval of edges going in or out of a node. 4. Ability to store any object in the node. 5. Ability to have different types of archs and specify which types of archs do you want to get (and specifying a sort of mask to get several types of archs). 6. The graph needs to be directed. 7. The graph must not enforce connectivity (forest). 8. The graph must remove all edges in or out of a node if the node is removed. 9. O(1) answer if an edge (n,m) exists. 10. O(1) tag a specific node as visited. 11. O(1) get roots of all trees. 12. The graph is supposed to provide fast translation between module names to nodes (or is it not the job of the graph ?).

The idea is for this object to always know what needs rebuilding. Each object can say whether it responds to triggers or not and do whatever it needs to update this information.

The object (graph) needs to supply (quickly) the forest of things to be done.

TEST($)

Test suite for this module. The test currently does nothing.

SUPER CLASSES

Meta::Graph::Directed(3)

BUGS

None.

AUTHOR

        Name: Mark Veltzer
        Email: mailto:veltzer@cpan.org
        WWW: http://www.veltzer.org
        CPAN id: VELTZER

HISTORY

        0.00 MV perl quality change
        0.01 MV perl code quality
        0.02 MV more perl quality
        0.03 MV more perl quality
        0.04 MV perl documentation
        0.05 MV more perl quality
        0.06 MV more perl code quality
        0.07 MV revision change
        0.08 MV languages.pl test online
        0.09 MV misc fixes
        0.10 MV spelling and papers
        0.11 MV PDMT/SWIG support
        0.12 MV Pdmt stuff
        0.13 MV perl packaging
        0.14 MV md5 project
        0.15 MV database
        0.16 MV perl module versions in files
        0.17 MV movies and small fixes
        0.18 MV thumbnail user interface
        0.19 MV more thumbnail issues
        0.20 MV website construction
        0.21 MV web site automation
        0.22 MV SEE ALSO section fix
        0.23 MV teachers project
        0.24 MV md5 issues

SEE ALSO

Meta::Class::MethodMaker(3), Meta::Graph::Directed(3), Meta::Utils::Output(3), strict(3)

TODO

-enable to build methods to stop on errors.