[Noisebridge-discuss] Bay Categories & Types -- 2010-02-11 PST Meeting Notes

[Jason Dusek]

  The meeting was held in the Alonzo Church classroom. Tea cakes
  (chocolate & banana bread) and almonds were served. Next time,
  I'll bring some decent tea.


  Attending: Vlad, Mikael, myself, Nicholas, Ian & Rebecca.


  The meeting opened with some material from the text: a simple
  problem on functors and a discussion of the "map-lifting
  property".


  I brought up comonadic IO for discussion but little progress
  was made.


  Nicholas wished to talk about type specifications and how we
  use them for correctness in functional programming. We
  discussed the specific examples of trees.


  Vlad sketched out a tree datatype and mentioned that it should
  be a poset, too. Mikael objected to this and objected to
  calling these rooted datatypes trees. Turns out in graph
  theory, trees are a different thing:

    http://en.wikipedia.org/wiki/Tree_%28graph_theory%29

  The tree data structure of CS fame is an "arborescence" to
  graph theorists:

    http://en.wikipedia.org/wiki/Arborescence_%28graph_theory%29

  There was also some discussion of pointers and identity.


  Really, though, Nicholas's ideas about specification involved
  a notion of functors and so we came back to those. Vlad and
  Mikael presented on the list monad and fixed points were
  briefly introduced.


  Somewhere in all this, Ian mentioned he had to go. We all
  opted to leave at that point. Vlad and I will continue on in
  Chapter 3, "Functors", and do a few problems.

--
Jason Dusek