3 Oct
2012
3 Oct
'12
2:17 p.m.
Hi,
On Wed, Oct 3, 2012 at 7:52 PM, Henning Thielemann
I wondered whether there is a brilliant typing technique that makes Data.Map.! a total function. That is, is it possible to give (!) a type, such that m!k expects a proof that the key k is actually present in the dictionary m? How can I provide the proof that k is in m? Same question for 'lab' (import Data.Graph.Inductive(lab)). That is, can there be a totalLab, with (totalLab gr = fromJust . lab gr) that expects a proof that the node Id is actually contained in a graph?
Perhaps by using a HList in the type of the Map? -- Johan