Module_or_macro

Module or Macro ?

While it is fairly obvious to choose between writing a macro or developing a module with some practice it may not be at the beginning.

What is a macro ?

A macro is a jython (python on Java virtual machine) program that navigates through, creates or modifies model elements. It can be associated with a menu entry or toolbar button or it can be written and executed directly from the macro window. It can also have its own GUI.

Comparison between macro and module

Feature	Module	Macro
Model navigation, modification, creation	Yes	Yes
Definition of stereotype, tag type, note type.	Yes	No
Definition of property page	Yes	No
Menu customization	Yes	Limited : at best it can have it’s own menu entry under ‘Macro’ entry or a button in the tool bar
Menu customization responsibility	Module developer	Macro user
Definition of parameter	Yes	No
Definition of palette tool	Yes	No
Model event handler	Yes	No
Delivery format	A jmdac archive with jar files, icons, internationalized messages	A python file

Back to the initial question, a macro will be preferred to a module when:

• no extension is required (stereotype, etc);

• its use is limited (model transformation or correction at module version update);

• sources are not expected to be managed apart (a macro is a python source file)

Developing a module is more time and resource consuming because it involves to tweak XML files, to write Java code, to compile, to package module, etc.

Macros are also impressively fast to process large models. So processing time is definitively not a criterion to choose between macro and module.

The rule of thumb is : Never develop a new module when a macro can do it.

For more information about macros, see Scripts and Macros.

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