Update: The new Scriptus project by Ian Sollars has very similar goals to the Weaver engine. When Plan A gets resumed, it will probably be based on/in collaboration with his work.
Plan A is to build a prototype based on the JRE/Rhino/Narwhal platform.
Narwal will be the package manager and core library for weaverengine.
A sandboxed environment will be created for each user script that is executed.
A custom datastore API will be exposed, with granular security.
An ouput API will also be exposed, with granular security and injection prevention.
Libraries and frameworks
Visit the resources pages for details on why
So far, here are the top options (or only picks):
User code execution runtime: Rhino
User code syntax: JavaScript or CoffeeScript
Web framework: ? / Play / RingoJS / NitroJS / Narwhal
(Can be anything that runs on the JRE, although Rhino-based would probably be better)
Persistence engine: ?
Source code editing: ACE
Output syntax: Markdown variant
Visual code editor: Flow-layout, using a modified Jison/OMeta/PEG.js grammer to maintain whitespace and comments, and to allow bi-directional conversion.