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boto

0.0.1
0.0.1

A library to unify data sources through attribute modeling in a seamless graph. Inspired by Pathom.

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boto src boto_graph.erl
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src/boto_graph.erl 

%% @private

-module(boto_graph).



-export([start/0, add_vertex/2, add_edge/4, path/3]).



start() ->

    digraph:new([cyclic]).



add_vertex(Graph, Vertex) ->

    digraph:add_vertex(Graph, Vertex).



add_edge(Graph, Vertex1, Vertex2, Label) ->

    digraph:add_edge(Graph, Vertex1, Vertex2, Label).



path(Graph, Vertex1, Vertex2) ->

    Path = digraph:get_short_path(Graph, Vertex1, Vertex2),

    build_path(Path, [], Graph).



get_edge(Graph, Vertex1, Vertex2) ->

    Edges = digraph:edges(Graph, Vertex1),

    Edges1 = [digraph:edge(Graph, E) || E <- Edges],

    Edges2 = [E || E <- Edges1, element(3, E) == Vertex2],

    Edges3 = [element(4, E) || E <- Edges2],

    hd(Edges3).



build_path(false, _Path, _Graph) ->

    [];

build_path([Vertex1, Vertex2], Path, Graph) ->

    Edge = get_edge(Graph, Vertex1, Vertex2),

    lists:reverse([Edge | Path]);

build_path([Vertex1, Vertex2 | Rest], Path, Graph) ->

    E = get_edge(Graph, Vertex1, Vertex2),

    build_path([Vertex2 | Rest], [E | Path], Graph).