Refactor

[epost]

• [ ] Document; add doc comments, etc.
  • [ ] Document Collage
• [ ] lookup2
• [ ] Use Foldable, etc. instead of List
• [ ] eliminate Prelude.-prefixed function applications, e.g. Prelude.map (also consider Set.map)
• [ ] align and indent stuff properly
• [ ] Look at existentials, constraint kinds, ...
• [ ] ADT instead of Stringly typed errors
• [ ] Factor out common code
• [ ] eliminate fromJusts if possible
• [ ] ...

[wisnesky]

• use folds instead of recursion
• the common idiom for (x in X) { updateInPlace(A,x), updateInPlace(B,x),...} gets 'shredded' into a collection of maps over X in Haskell in many places. These places should probably use the state monad.