On Wed, Jun 3, 2009 at 8:59 AM, Nico Rolle
hi there
heres a code snipped, don't care about the parameters. the thing is i make a lookup on my map "m" and then branch on that return value
probePhase is sc [] m = [] probePhase is sc (x:xs) m | val == Nothing = probePhase is sc xs m | otherwise = jr ++ probePhase is sc xs m where jr = joinTuples sc x (fromMaybe [] val) key = getPartialTuple is x val = Map.lookup key m
the line "jr = joinTuples sc x (fromMaybe [] val)" is kind of ugly because i know that it is not Nothing.
Although pattern matching is probably nicer, there's also fromJust which will throw an exception if you pass it Nothing. I prefer: case Map.lookup key m of Nothing -> next Just val -> (joinTuples sc x val) ++ next where next = probePhase ... key = ...