abs_graph.sa


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---------------------------> Sather 1.1 source file <--------------------------
-- Author: Benedict A. Gomes <gomes@samosa.ICSI.Berkeley.EDU>
-- Copyright (C) 1995, International Computer Science Institute
-- COPYRIGHT NOTICE: This code is provided WITHOUT ANY WARRANTY
-- and is subject to the terms of the SATHER LIBRARY GENERAL PUBLIC
-- LICENSE contained in the file: Sather/Doc/License of the
-- Sather distribution. The license is also available from ICSI,
-- 1947 Center St., Suite 600, Berkeley CA 94704, USA.


abstract class $GRAPH{NTP<$HASH,ETP< $EDGE{NTP}} < $ELT{NTP}, $STR

abstract class $GRAPH{NTP<$HASH,ETP< $EDGE{NTP}} < $ELT{NTP}, $STR is -- A generic graph, consisting of a bunch of nodes and edges. -- There is no committment as to the meaning of the edges -- Every node has some edges which associate it with a set of -- neighbors -- This generic graph does not have the modification operations -- Design note: -- The reason for not having the modification operations is that -- it is hard to work on a general graph without knowing whether it -- has directed or undirected edges -- Acknowledgement: -- Discussions with the Karla folk, particularly Wolf, helped -- elucidate some of the confusion between directed and undirected -- graphs is_empty: BOOL; -- Return true if there are no nodes in the graph copy: $GRAPH{NTP,ETP}; -- Return a copy of the graph n_nodes: INT; -- Return the number of nodes in the graph n_edges: INT; -- Return the number of edges in the graph has_node(n: NTP): BOOL; -- Return true if this graph has the node "n" has_edge(e: ETP): BOOL; -- Return true if this graph has the edge "e" n_adjacent(n: NTP): INT; -- Return the number of nodes that are adjacent to "n". -- See the note at "adjacent!" node!: NTP; -- Yield all the nodes in the graph edge!: ETP; -- Yield all the edges in the graph adjacent!(once n: NTP): NTP; -- This corresponds more closely to the notion of neighbors in an -- undirected graph. In the case of a directed graph, the neighbors -- will be the set of outgoing nodes. -- In other words, by going through all nodes and their adjacent -- nodes we can construct all the edges in the graph without -- duplication. end; -- class $GRAPH{NTP,ETP}