On 7/16/07, Claus Reinke <[EMAIL PROTECTED]> wrote:
enjoy (i hope:-),
Very much. Work hasn't been so much fun since.... Well, for a long time. :-)
One small question, which might reveal if I've understood things aright.
(do (v,e) <- dmin' l
(do guard e
me <- empty m
re <- nullT r
write m p (v,me && re))
`mplus` return ((v,e)))
`mplus` (do v <- readTVar' m
re <- nullT r
write m p (v,re))
`mplus` (do (v,e) <- dmin' r
when e $ writeTVar' p Empty
return ((v,e)))
`mplus` error "emit nasal daemons"
If I refactor this a little into dminLeft dminMiddle and dminRight, I
believe I should be able to replace this with:
...
msum [dminLeft l m r, dminMiddle m r, dminRight r, error "emit
nasal daemons"]
where
dminLeft l m r = do
(v,e) <- dmin' l
(do guard e
me <- empty m
re <- nullT r
write m p (v,me && re)) `mplus` return (v,e)
dminMiddle m r = do
v <- readTVar' m
re <- nullT r
write m p (v,re)
dminRight r = do
(v,e) <- dmin' r
when e $ writeTVar' p Empty
return (v,e)
....
Is this correct? And if so, is GHC likely to do constant folding on
msum over the list skeleton?
T.
--
Dr Thomas Conway
[EMAIL PROTECTED]
Silence is the perfectest herald of joy:
I were but little happy, if I could say how much.
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