NAME

Math::PartialOrder::Std - standard iterative class for partial orders (datatype hierarchies).

SYNOPSIS

  use Math::PartialOrder::Std;

  # ... any Math::PartialOrder::Base method

REQUIRES

Math::PartialOrder, Carp, Exporter

DESCRIPTION

Math::PartialOrder::Std is a Math::PartialOrder::Base implementation for rooted finite partial orders (datatype hierarchies) which uses hash-references to store and manipulate hierarchy information. The hashrefs used have keys which are eq to their values.

Math::PartialOrder::Std inherits from Math::PartialOrder::Base, and implements all required methods described in Math::PartialOrder::Base.

METHODS

Construction & Initialization

• new( {root=>$r} )

  Creates and returns a new Math::PartialOrder::Std object rooted at $r, which defaults to 'BOTTOM'.

Additional Hierarchy Methods

• _ancestors($type)

  Returns the ancestors of $type as a hash reference.

• _descendants($type)

  Returns the descendants of $type as a hash reference.

• _minimize(\%hash)

  Destructively minimizes the values of the hash-reference \%hash. Returns \%hash.

• _maximize(\%hash)

  Destructively maximizes the values of the hash-reference \%hash. Returns \%hash.

Hierarchy Maintainence: Low-level Accessors/Manipulators

• _types()

  Returns the hashref whose values represent all of the types in the hierarchy.

• _root(), _root($r)

  Get/set the root of the hierarchy.

• _parents(), _parents($type)

  With no arguments, returns a reference to a hash keyed by type whose values are hashrefs representing the parents of the keying type.

  With one argument, returns the hashref representing the parents of $type.

• _children(), _children($type)

  With no arguments, returns a reference to a hash keyed by type whose values are hashrefs representing the children of the keying type.

  With one argument, returns the hashref representing the children of $type.

• _attributes(), _attributes($type), _attributes($type, $hashref)

  With no arguments, returns a reference to a hash of attribute-hashes keyed by type. With one argument, returns a reference to the attributes for $type. With 2 arguments, sets the attributes for $type to $hashref.

ACKNOWLEDGEMENTS

perl by Larry Wall.

Usage of hash-references as sets draws heavily on Jarkko Hietaniemi's Set::Scalar module.

AUTHOR

Bryan Jurish <jurish@ling.uni-potsdam.de>

COPYRIGHT

Copyright (c) 2001, Bryan Jurish. All rights reserved.

This package is free software. You may redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO

perl(1). Math::PartialOrder(3pm). Math::PartialOrder::Base(3pm). Math::PartialOrder::Caching(3pm). Math::PartialOrder::LRUCaching(3pm). Math::PartialOrder::CMasked(3pm). Math::PartialOrder::CEnum(3pm). Math::PartialOrder::Loader(3pm). Set::Scalar(3pm).