lang2 release

Documentation is at lang2 and source at lang2.arc

• Added an option to run the Lang program in a simple subprocess.

  The single threaded event server is an elegant and high performance approach, but requires that the Lang code does its I/O using the event server facilities; so it is a poor choice for Lang libraries that do normal blocking I/O.

  The subprocess style has the advantage that Lang calls are completely independent so they can do I/O or even load incompatible libraries without a problem... though it has the disadvantage of having to load Lang and needed libraries on every call.

  I’m guessing a forking Lang server would be a good choice for libraries that do “normal” blocking I/O, though I haven’t implemented one yet.

• I was able to both simplify and generalize the template syntax; always a nice combination to be able to do.
• I’m now using “scheme” to escape out to PLT Scheme, instead of “ac-scheme”, “mz”, or “$”. I was quite seduced when I noticed that Arc’s period syntax could be used to reference a Scheme function: scheme.display expands into (scheme display), and so (scheme.display foo) calls the Scheme function display with the Arc expression foo. The updated hack is at scheme0