A "not-very-Haskelly" API for calculating traversals of graphs that may be too large to fit into memory. The algorithms included are inspired by the visitor concept of the Boost Graph Library. Here is a very simple example of how we might execute a depth-first-search. In this case the visitor simply collects the edges and vertices in the order that the corresponding functions get called. After the necessary imports, create an adjacency list where the vertices are labeled with integers.