Make optional spkg for gfsage

[kcrisman]

The EU "Molto" project has created a prototype of getting natural language to interface with Sage - see the  starting webpage. This can be used as

•  an interface
•  an evaluation percent directive within Sage.

----------------------------------------------------------------------
| Sage Version 4.8, Release Date: 2012-01-20                         |
| Type notebook() for the GUI, and license() for information.        |
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sage: 2+2
4
sage: %english

  --> Switching to Gf <-- 

No autocompletion available
''
english: compute the sum of 2 and 2.
4
english: 

  --> Exiting back to Sage <-- 

sage: 

This is accomplished by some pretty minor changes in setup.py and adding a couple interface files in various places. We would *not* make this a standard package, ever, because the  dependencies include Haskell and the grammatical framework  GF.

So why not?

[jason]

Nice. Can I suggest a tremendously helpful improvement? Can you print out the Sage code that is executed? That would help people learn the syntax and let them double-check the natural language parsing.

[kcrisman]

Well, their goal is somewhat different from ours. But maybe that could be an option in the main program, which we would enable by default in a Sage optional spkg.