On Sat, Dec 05, 2009 at 02:13:10PM -0800, Gregory Crosswhite wrote:
The problem comes from the fact that = takes a *function* as its
second argument, and so if the first argument is an error then we
can't evaluate the second argument in order to see if it has an
error as well.
Hmm, that's
On Sun, Dec 06, 2009 at 03:50:55PM -0500, Brent Yorgey wrote:
So what we have here, it seems, is a type with at least two reasonable
Applicative instances, one of which does *not* correspond to a Monad
instance. My argument is that it is very strange (I might even go so
far as to call it a
On Thu, Dec 03, 2009 at 01:50:06PM -0800, Gregory Crosswhite wrote:
Or, even more concisely:
==
sumWithError_3 = liftM2 (+)
==
Unfortunately though, neither of these definitions have the
Recall that the definition of liftM2 is
==
liftM2 :: (Monad m) = (a1 - a2 - r) - m a1 - m a2 - m r
liftM2 f m1 m2 = do { x1 - m1; x2 - m2; return (f x1 x2) }
==
which, if I understand
In particular, the motivation for this package was that I have written
a build system, and I wanted to collect as many errors in the build as
possible and show them all to the user at once.
YMMV, but at least for me a deluge of errors is less helpful than a
short list I can fix quickly, then
Gregory Crosswhite schrieb:
If there is one thing that we really don't have enough of in Haskell, it is
*ways to handle errors*! Thus, I am pleased to announce the release of the
error-message package to help in filling this, erm, gap.
This philosophy behind this package is that it is
On Dec 4, 2009, at 7:55 AM, Henning Thielemann wrote:
Gregory Crosswhite schrieb:
If there is one thing that we really don't have enough of in Haskell, it is
*ways to handle errors*! Thus, I am pleased to announce the release of the
error-message package to help in filling this, erm, gap.
If there is one thing that we really don't have enough of in Haskell, it is
*ways to handle errors*! Thus, I am pleased to announce the release of the
error-message package to help in filling this, erm, gap.
This philosophy behind this package is that it is often better to find out all
of the
