(*
 * graph.sml - Graph Concepts 
 *)

(* Copyright 2003, Trustees of Indiana University
 * Please see the license in the file ../LICENSE
 *)

(* $Id: graph.sml,v 1.2 2003/05/02 20:03:38 jewillco Exp $ *)


signature GraphSig = 
sig
    type graph_t
    eqtype vertex_t
end

signature EdgeGraphSig =
sig
    include GraphSig
    type edge_t
    val source : graph_t -> edge_t -> vertex_t
    val target : graph_t -> edge_t -> vertex_t
end

signature IncidenceGraphSig = 
sig
    include EdgeGraphSig
    val out_edges : graph_t -> vertex_t -> edge_t list
end

signature BidirectionalGraphSig = 
sig
    include IncidenceGraphSig
    val in_edges : graph_t -> vertex_t -> edge_t list
end

signature AdjacencyGraphSig = 
sig
    include GraphSig
    val adjacent_vertices : graph_t -> vertex_t -> vertex_t list
end

signature VertexListGraphSig = 
sig
    include GraphSig
    val vertices : graph_t -> vertex_t list
    val num_vertices : graph_t -> int
end

signature EdgeListGraphSig = 
sig
    include EdgeGraphSig
    val edges : graph_t -> edge_t list
end