Improve code length and structure when returning binary operations e.g. sum of integers

Ignore-this: adf4d2c0f0a2d23b00b67f6c7c61d644

darcs-hash:20130211144623-c3db2-19d78731c90af336e4261880894010e3b5234a4c
Pattern match on Appt only, and discard the type of the response (since it doesn't occur to me how to encode this type in the type system). Discard also the var that represents the function call to the appt (since we will have them loaded instead of called, FOR NOW)

Ignore-this: b797e5561828737c4dd9e9e6cf681f5c

darcs-hash:20130211152720-c3db2-4370500166b43ab9fd37574d316a8c7053cb3c2b
Merge branch 'master' of https://github.com/kmels/haskell-dart