Why is it called "EMF Generator _Model_"?

Question

In the Eclipse Modeling Framework (EMF), there are ecore files to define a model. From this model code (and other things) can be generated. This generation step is described by an "EMF Generator Model". Now my question is, why this file is called "model" instead of "configuration" or something like that. In my opinion, it does not model anything, but it describes a generation step...

Answer 1

While the other answers are perfectly correct, there is one additional difference between a "model" and a "configuration". All EMF models (including this generator model) can be modified, transformed and so on by every already available EMF tool (because they all use the same meta model).

This is a huge difference compared to the situation that the configuration can only be read by another tool, if it knows the exact format of the configuration serialization.

So you can create an UML diagram of the generator model, you can use it in a model based graphical editor, you can transform it using model-to-model transformation plugins, you can put it into EMFstore, ... without any of these tools having been prepared specifically for that model.

Answer 2

The current implementation of EMF was created with a bootstrapping-approach. At first, the model that describes the data that is stored in ecore and genmodel were written by hand. As soon as EMF was stable enough, these were modeled and generated with EMF itself. This means, the ecore and genmodel are in every way a EMF model.

This is similar to how many compilers for new programming languages are developed. The initial implementation has to be written in a second language, but as soon as the compiler is complete, you can use the new language to write a new implementation, add features, and then use the binaries of the previous version of the compiler to create the next.

From the creator of EMF, Ed Merks:

After all, EMF's generator model generates both the Ecore model and itself, so we're not actually in a position to delete our generated code. We need it to bootstrap the environment. It's prickly problem. http://ed-merks.blogspot.de/2008/10/hand-written-and-generated-code-never.html

Answer 3

Actually the genmodel as well as the ecore files are also EMF models technically speaking. So this is not a surprise that it is called this way.

In fact you have to understand that EMF allows to describe any kind of structured information. So it can be used to describe your own semantics as well as describe code generation configurations or even describe itself (ecore).