Add Sten Vercammen's pattern matching library (ported to Python 3, numpy dependency replaced by standard library)

pattern_matching/graphToDot.py

@@ -0,0 +1,44 @@
+# coding: utf-8
+
+"""
+Author:		Sten Vercamman
+			Univeristy of Antwerp
+
+Example code for paper: Efficient model transformations for novices
+url: http://msdl.cs.mcgill.ca/people/hv/teaching/MSBDesign/projects/Sten.Vercammen
+
+The main goal of this code is to give an overview, and an understandable
+implementation, of known techniques for pattern matching and solving the
+sub-graph homomorphism problem. The presented techniques do not include
+performance adaptations/optimizations. It is not optimized to be efficient
+but rather for the ease of understanding the workings of the algorithms.
+The paper does list some possible extensions/optimizations.
+
+It is intended as a guideline, even for novices, and provides an in-depth look
+at the workings behind various techniques for efficient pattern matching.
+"""
+
+import graph as mg
+
+def printGraph(fileName, graph, matched_v={}, matched_e={}):
+	if not isinstance(graph, mg.Graph):
+		raise TypeError('Can only print Graph Graphs')
+
+	with open(fileName, 'w') as f:
+		f.write('digraph randomGraph {\n\n')
+		for str_type, plan_vertices in graph.vertices.items():
+			for plan_vertex in plan_vertices:
+				vertex_str	= str(id(plan_vertex)) + ' [label="'+str(str_type)+'"'
+				if plan_vertex in list(matched_v.values()):
+					vertex_str	+= ', style=dashed, style=filled]\n'
+				else:
+					vertex_str	+= ']\n'
+				f.write(vertex_str)
+				for out_edge in plan_vertex.outgoing_edges:
+					edge_str	= str(id(plan_vertex)) + ' -> ' + str(id(out_edge.tgt)) + ' [label="'+str(out_edge.type)+'"'
+					if out_edge in list(matched_e.values()):
+						edge_str	+= ', style=dashed, penwidth = 4]\n'
+					else:
+						edge_str	+= ']\n'
+					f.write(edge_str)
+		f.write('\n}')