Registry {
  (@
  GeneratedCodeCategory get_generatedCategory(String name)
    throws ParseException
  {
      CodeCategory result = get_category(name);
      if( ! (result instanceof GeneratedCodeCategory))
        throw new ParseException("Not a GeneratedCodeCategory: "+name);
      return (GeneratedCodeCategory)result;
  }
  @)
  void generateCode(GeneratedCodeCategory category,CmdArgs args) (@
    SourceList sources = new SourceList();
    generateEntityCode(category,args,sources);
    if( ! sources.isEmpty())
      // initialize a macro table
      category.expandMakeTemplate(/*macros, */args,sources);
  @)
  private void generateEntityCode(
                                  GeneratedCodeCategory category,
                                  CmdArgs args,
                                  SourceList sources)
    bypassing ParentEntity to Entity
  {
    (@
      private Registry registry;
    @)
    before Registry (@
      registry = host;
    @)
    before Entity (@
      final String entityName = host.get_name().get_value();
      if(category.get_keys().intersects(host.get_keys())){
        System.out.println("  Generating source for: "+entityName);
        ExpansionContext context = new ExpansionContext();
        host.collectContext(context,category.get_keys());
        MacroTable macros = new MacroTable();
        registry.addMacros(macros,host);
        String thisClassName = category.className(host);
        macros.define("ThisClass",thisClassName);
        macros.define("ThisClassHeader",
                      category.headerFile(host).toString());
        macros.define("ThisClassHeaderKey",
                      thisClassName.toUpperCase()+"_H");
        category.expandEntityTemplates(context,macros,args,sources);
      }
    @)
  }
  void addMacros(MacroTable macros,Entity entity)
    to CodeCategory
  {
    before CodeCategory (@
      String name = host.get_macroBaseName();
      macros.define(name,host.className(entity));
      macros.define(name+"Header",host.headerFile(entity).toString());
    @)
  }
}
Entity {
  void collectContext(ExpansionContext context, AccessKeyList keys)
    to TypeUse
  {
    before Entity(@
      if(context.get_entity() == null)
        context.set_entity(host);
    @)
    around Method (@
      // The buck stops at unqualified Methods :-)
      if(host.get_keys().intersects(keys)){
        context.add(host);
        subtraversal.apply();
      }
    @)
    before TypeUse (@
      context.add(host);
    @)
  }
}
ExpansionContext{
  (@ Hashtable useMap; @)
  init (@
    useMap = new Hashtable();
    methods = new MethodList();
    useage = new TypeUseList();
    entity = null;
  @)
  void add(Method method) (@
    get_methods().add(method);
  @)
  void add(TypeUse newUse) (@
    final String key = newUse.get_typeName().get_value();
    TypeUse use = (TypeUse)useMap.get(key);
    if(use == null){
      use =
        new TypeUse(
          newUse.get_typeName(),
          false,
          newUse.get_type());
      useMap.put(key,use);
      useage.add(use);
    }
    if(newUse.get_needHeader())
      use.set_needHeader(true);
  @)
}
GeneratedCodeCategory{
  void expandEntityTemplates(ExpansionContext context,
                             MacroTable macros,
                             CmdArgs args,
                             SourceList sources)
    to {HeaderTemplate,ImplTemplate}
  {
    (@
      GeneratedCodeCategory category;
    @)
    before GeneratedCodeCategory (@
      category = host;
    @)
    before HeaderTemplate (@
      File outDir = args.getHeaderOutDir();
      if(outDir != null){
        File headerFile = category.headerFile(context.get_entity());
        String headerFileName = headerFile.getName();
        macros.define("File",headerFileName);
        File outFileSpec = new File(outDir,headerFileName);
        try {
          PrintWriter outFile =
            new PrintWriter(new FileWriter(outFileSpec));
          host.expand(outFile,context,macros,args);
          outFile.close();
        }
        catch(IOException e){
          Main.die(e);
        }
      }      
    @)
    before ImplTemplate (@
      File outDir = args.getImplOutDir();
      if(outDir != null){
        File implFile = category.implFile(context.get_entity());
        String implFileName = implFile.getName();
        sources.add(implFileName);
        macros.define("File",implFileName);
        File outFileSpec = new File(outDir,implFileName);
        try{
          PrintWriter outFile =
            new PrintWriter(new FileWriter(outFileSpec));
          host.expand(outFile,context,macros,args);
          outFile.close();
        }
        catch(IOException e){
        }
      }
    @)
  }
  void expandMakeTemplate(CmdArgs args, SourceList sources)
    to MakeTemplate
  {
    before MakeTemplate (@
      if(args.getImplOutDir() != null){
        System.out.println("Expanding Make Template");
      }
    @)
  }
}