abs_digraph.sa

 
---------------------------> Sather 1.1 source file <--------------------------
-- 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 $RO_DIGRAPH{NTP} < $GRAPH{NTP,DIEDGE{NTP}} 
abstract class $RO_DIGRAPH{NTP} < $GRAPH{NTP,DIEDGE{NTP}} is
   -- NTP is the type of the node i.e. the type of the unique node
   -- index.  This is a read-only digraph abstraction. No modifying
   -- operations are permitted. Most views of digraphs are of this
   -- type
   
   
   -- Inherits:
   -- size: INT; str: STR; has(n: NTP): BOOL; elt!: NTP;
   -- n_nodes:INT,n_edges:INT,n_adjacent(n: NTP): INT
   -- node!: NTP, edge!:DIEDGE{NTP}, adjacent!(n:NTP):NTP
   -- has_node(n: NTP):BOOL, has_edge(n:NTP):BOOL
   
   copy: $RO_DIGRAPH{NTP};
   -- Create a copy of this digraph. The copy is also read-only
   
   n_incoming(n: NTP): INT;
   -- Return the number of incoming edges into the node "n"
   
   n_outgoing(n: NTP): INT;
   -- Return the number of outgoing edges from the node "n"

   --              ------ Cursor --------------------------
   incoming!(once n: NTP): NTP;
   -- Yield the incoming edges into the node "n". No ordering
   -- is guaranteed
   
   outgoing!(once n: NTP): NTP;
   -- Yield the outgoing edges from the node "n"
   
   -- Equality testing
   equals(g: $RO_DIGRAPH{NTP}): BOOL;
   -- Return true if the self and "g" have the same structure and the
   -- same nodes. The nodes must be the *same* (i.e. =), and in
   -- both graphs the must be the same edges between nodes
   
end;


abstract class $DIGRAPH{NTP} < $RO_DIGRAPH{NTP}  
abstract class $DIGRAPH{NTP} < $RO_DIGRAPH{NTP}  is
   -- A directed graph that permits the addition of new nodes and edges.

   add_node: NTP;
   -- Add a new node to the graph. Returns the node index

   add_node(n: NTP): NTP;
   -- Add the node "n" to the graph. Return a node index.  The node
   -- index that is returned may be the same as the original node
   -- index, if that is appropriate for this graph, or maybe a new
   -- object.  The user of this function should make no assumption
   -- about the relationship between the node that is added and the
   -- index that is returned.
   
   connect(e: DIEDGE{NTP});	
   -- Add the edge "e" which connects the nodes "e.first" to
   -- "e.second"

   delete_node(n: NTP);
   -- Delete the node index "n"

   disconnect(e: DIEDGE{NTP});	
   -- Delete the edge specified by "e". Does nothing if
   -- "e" does no exist

end;