# Sorting, Seen Functionally _and_ Type Holes

• Apr 23, 2014 · 7:00 PM

7pm: The Hole Type and Nothing But the Type, by Stephen Compall

This talk will demonstrate GHC's new Type Holes feature, focusing on how it can help beginners learn to think about types in Haskell, and guide them in writing correct code.

8pm: Sorting algorithms through the eyes of a functional programmer, by Daniel James

Everyone knows sorting algorithms like bubble sort, insertion sort, selection sort, and quicksort. Maybe some already have an intuition that insertion and selection sort are closely related. This talk will dig into the details of folds and calculating with types. This sort of categorical, algebraic approach lets us think about algorithms and their specifications in a whole new light. In so doing, we will distill these sorts down to their essence, appreciating the duality that appears and specifying the mechanisms by which these different algorithms relate to one another.

(For those who aren't, we promise the talk will be more accessible than the paper!)

• ##### Anne M.

Thank you all! Two questions. 1.Is there a Git repo for the practices on Holes? 2.Also, is there an online copy of the more introductory paper, "A Duality of Sorts"? (All I found was http://link.springer.com/chapter/10.1007%2F978-3-642-40355-2_11 )

April 23, 2014

• ##### Stephen C.

Re 1: You can find a Bazaar branch at http://ur1.ca/h5m6j­ . r7 (the branch head) reflects the final state after the presentation; r6 is how it started.

1 · April 24, 2014

• ##### Anne M.

I am really looking forward to Holes. Maybe I should go with MightyByte's idea of abandoning HP, but right now I'm using it, which has 7.6.3. There's a rumor by yitz, 11 days ago, that 7.8.2 GHC is coming to the Haskell Platform installer (HP), in a month or two.
http://www.reddit.com...­

April 24, 2014

• ##### Daniel J.

3 · April 24, 2014

• ##### Anne M.

hi! if I come early, like 6.30p (I think that's ok because Pivotal has a nice lobby, right? Pivotal is so great to us!) would one of you experts be willing to help me figure out how to contribute to Stylish-Haskell? I have a ticket I'm trying to grok how to do it. thank you!! https://github.com/jaspervdj/stylish-haskell/issues/39

April 23, 2014

• ##### Gershom B.

I'm sure someone will be around early who's up for looking at the problem. I've looked at haskell-src-exts before though for this sort of thing, and it actually may be tricky :-)

1 · April 23, 2014

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