Code generation layers (API) for modules

A powerful component of Drupal is the Module system which is the strength of Drupal as an open source web development ecosystem. Because of the clever design of the "hook" system, it is easy for developers to provide functionality and features that work smoothly with the core and other modules if the developers follow the published APIs.

As Drupal getting bigger, for every major version of Drupal core, the task of updating modules becomes exponentially bigger and more complex because of the drastic changes in core APIs and the interconnections among core and contributed modules. Both developers and end users demand simpler and quicker solutions, otherwise the lag between newly released core and full productions will become so big that users (and module developers) won't have the energy and patience to catch up with the core at all.

A solution I propose here is based on the ideas of declarative programming and code generation.

Drupal already has two powerful systems to generate SQL and XTHML. They are proved to be effective and productive in building complicated interactive systems.

If we follow the same patterns in database and theme systems to design code generation layers for modules that not only validate but automatically generate code according to the new APIs, it would save a lot of time in module migration and maintenance. The implementation can be done in the fashion of theme engines or XSLT.

The code generation layers could work in three stages:

• Convert existing modules into template + meta data
• Code review and debug on template and meta data
• Assemble module code in install profile, features, pluggin manager, etc.

The last stage can be configured (again with meta data) for development, testing, and production separately and live in separate version control system.

This approach might solve many problems raised in http://groups.drupal.org/node/24709.

I am not familiar enough with Drupal system to actually implement this but I think many people in the community can. If it is too late before the D7 code freeze, then we could do it in Drupal 8.