YB. I am very worried about this proposal. It looks again like we would be
creating another language to replace one we already have, namely python,
mainly so that we could have introspection and programmable changes
into an existing control flow structure (e.g. the standard DBN code).

I feel that the negatives outweigh the advantages.

Please correct me:

Disadvantages:

* much more difficult to read
* much more difficult to debug

Advantages:

* easier to serialize (can't we serialize an ordinary Python class created by a normal user?)
* possible but not easier to programmatically modify existing learning algorithms 
  (why not the usual constructor parameters and hooks, 
   when possible, and just create another code for a new DBN variant when it can't fit?)
* am I missing something?

I am not convinced that any of the stated advantages can't be achieved in more traditional ways.