passedTypes = new HashSet();   toplevel.accept(this, null, true);
    public StructureIncludeFile(SIRStructure[] structs, FlatNode toplevel, String dir)     {	try {	    FileWriter fw = new FileWriter(dir + "/structs.h");	    passedTypes = new HashSet();	    //determine which struct types are actually passed over channels	    toplevel.accept(this, null, true);	    createStructureDefs(structs, fw);	    if (!KjcOptions.standalone)		createPushPopFunctions(structs, fw);	    fw.close();	}	catch (Exception e) {	    e.printStackTrace();	    System.err.println("Error creating structure include file");	}    }