Semantic calculation for graph parsing

[gsvgit]

Meerkat supports semantic code specification, but it works only if the result of parsing is an SPPF with a single tree. SPPF is a compressed representation of parse forest. In case of graph parsing, we get an arbitrary SPPF which can contains an infinite set of trees. One of the possible solutions is lazy tree extraction. For each tree semantic code can be calculated by using existing methods. The result is a lazy collection of semantic values for each tree from SPPF.

• Implement BFS-based lazy trees extraction.
• Implement the interface for a user, which provides an ability to calculate semantic code for arbitrary parsing result.
• Implement tests.