This modules implements the abstract syntax and the build function for the signatures

This module implements the expand algorithm of Makoto Kanazawa's article "Parsing and generation as Datalog query evaluation" to deal with almost linear grammars.

This module implements basic operations on lambda terms. It uses de Bruijn indices.

Modules with this module type should provide Union-Find algorithms and the indexed storage data structure. Note that we take the opportunity of implementing from scratch such algorithms to allow the find function returns not only the index of the representative and the values it indexes, but also the storage data structure, so that the find algorithm can modify it, in particular with path compression.