24 Aug
2008
24 Aug
'08
9:36 a.m.
I haven't tried to run the code, but my first bet is that, due to the
rank-2 polymorphism of ST, you should use parenthesis instead of $ in
the case of runST.
On Sun, Aug 24, 2008 at 3:25 PM, Andrew Coppin
colour_grid :: (Particle -> IO ()) -> Grid ph -> IO () colour_grid fn g = sequence_ $ runST $ do ps <- grid_coords g
mapM (\pix -> do particle <- read_grid g pix return $ fn particle ) ps
When I attempt to run this, GHCi just gives me a very cryptic type checker error. I can't figure out what's wrong here. As far as I can tell, this should run...
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