:- module digraph.
:- interface.
:- import_module assoc_list.
:- import_module enum.
:- import_module list.
:- import_module map.
:- import_module pair.
:- import_module set.
:- import_module sparse_bitset.
:- type digraph(T).
:- type digraph_key(T).
:- type digraph_key_set(T) == sparse_bitset.sparse_bitset(digraph.digraph_key(T)).
:- instance (enum.enum(digraph.digraph_key(T))).
