Aligned role, support for undirected access and filtering

[michnov]

A new role Core::Node::Aligned for Core::Node, providing alignment accessors. It offers the original functions so far available in Core::Node as well as the additional functions from Tool::Align::Utils that access aligned nodes regardless the orientation of the links (undirected access). However, the two sources are not just stuck together in the target role. Functionality of some methods has been slightly modified. Namely:

get_aligned_nodes

• support for undirected access and filtering by language, selector and relation type
• never returns a couple of undefined values. If there are no counterparts, a pair of references to empty arrays are returned, for nodes and relation types, respectively
• if the method is called as it used to be called, i.e., with no parameters, it scans only the links in the specified direction, for the time being. It corresponds to the functionality of the previous version. However, since it is planned to be changed to undirected access, soon, the user is encouraged by a warning to use get_directed_aligned_nodes instead.

  get_directed_aligned_nodes, get_undirected_aligned_nodes

• the version of get_aligned_nodes with directed and undirected access, respectively
• get_directed_aligned_nodes does the same job as the original get_aligned_nodes (except that it does not return undefs), so all uses of get_aligned_nodes in Treex have been changed to get_directed_aligned_nodes

  is_aligned_to

• support for undirected access and filtering by language, selector and relation type
• if the method is called as it used to be called, i.e., with no parameters, it scans only the links in the specified direction, for the time being. It corresponds to the functionality of the previous version. However, since it is planned to be changed to undirected access, soon, the user is warn with the same warning as for the get_aligned_nodes method.

  is_directed_aligned_to, is_undirected_aligned_to

• the version of is_aligned_to with directed and undirected access, respectively
• is_directed_aligned_to does the same job as the original is_aligned_to, so all uses of is_aligned_to in Treex have been changed to is_directed_aligned_to

There is one additional method delete_aligned_nodes_by_filtercombining get_aligned_nodes and delete_aligned_node. In this case, undirected access is default, if not set differently by the filter.

[ closes #47 ]

[tuetschek]

It looks really good to me :+1: . Just a question – what are the methods that are left in Treex::Tool::Align::Utils?

[michnov]

Treex::Tool::Align::Utils remains heterogenous with:

• methods add_aligned_node and aligned_transitively that might be also included in Treex::Core::Node::Aligned but I was lazy to move them, refactor their calls and write documentation and tests for them :)
  • I would rather leave fixing it for later. I can make another issue for it if @martinpopel does not mind if it stays unresolved for a while
• methods aligned_robust and access_* used for rule-based alignment of coreferential expressions
• a debug method print_nodes that has nothing to do with alignment at all
  • I will delete it now

[martinpopel]

Good work, thanks. The remaining content of Treex::Tool::Align::Utils can be solved later.