Language infrastructure (reloaded)

Hello members,

I know, it was already partly discussed in the thread
http://forums.netbeans.org/viewtopic.php?t=65697&highlight=language+infrastructure

I wanted to start porting my simple language stucture based on the book "Rich
Client Programming: Plugging into the NetBeans Platform
<http://www.amazon.com/Rich-Client-Programming-Plugging-NetBeans/dp/0132354802>"
to a modern approach and try to document it as a or several tutorials.

Reading through the thread again to refresh my memory, I will probably base
my work on Quorum language (Thank yous Stefik) as well as what I can find
at https://github.com/GeertjanWielenga/Python4NetBeans.

I hope those projects use the "most" state of the art implementation for a
new language support. @Stefik and Geertjan, do you agree with this
statement?

Now there are still some questions that I would like to be answered to be
able to write a "clean" tutorial. Googling around and using information
stored in my spongy memory ;), there is/were different language APIs in NB
history.

First there is the old "roots" way described in Rich Client Programming
book that I used in the first place. Then there was Schliemann which seems
to be discontinued. Then came GSF which is partly documented/used in the NB
tutorials. But now it seems it is also becoming deprecated. Now there is
CSL.

Is CSL the new language infrastructure? It seems to have GSF parts in it,
since the csl.api readme.txt fle still makes references to GSF.

Now I am lost. Can someone here out explain me:
1) the history of the language infrastructures?
2) tell me what is infrastructure to use now (state of the art) and its
name (I have a hint but would prefer that someone confirms my idea)?

Help would be greatly appreciated.

Cheers,

Jean-Marc