# Create a dot file representing the class hierarchy of a model.
fun generate_class_hierarchy(toolcontext: ToolContext, mmodule: MModule)
do
	var buf = new FlatBuffer
	buf.append("digraph \{\n")
	buf.append("node [shape=box];\n")
	buf.append("rankdir=BT;\n")
	var hierarchy = mmodule.flatten_mclass_hierarchy
	for mclass in hierarchy do
		buf.append("\"{mclass}\" [label=\"{mclass}\"];\n")
		for s in hierarchy[mclass].direct_greaters do
			buf.append("\"{mclass}\" -> \"{s}\";\n")
		end
	end
	buf.append("\}\n")
	var f = new FileWriter.open(toolcontext.output_dir.join_path("class_hierarchy.dot"))
	f.write(buf.to_s)
	f.close
end