User Portlet User Portlet

Discussions
It this functionality available only in the commercial version, or I can play in online or community distro? Where can I find intro manuals or tutorials into meta extensions of WL (besides this post)?
Is WL suitable as learning workbench for computer languages design? I don't mean full-functional compiler, but interactive workbench able to visualize internal compiler/interpreter structures, parse BNF-defined grammars, process attribute grammar,...