On 05/01/06, John Meacham [EMAIL PROTECTED] wrote:
independent of anything else, giving up error messages on pattern match
failures in do notation is not acceptable. so, if the split were to
happen, having two methods in MonadZero, one which takes a string
argument, would be needed.
| What do people think of the following proposal? Remove fail from the
| Monad class. Reinstate MonadZero as a separate class as in Haskell
| 1.4.
This was debated extensively during the Haskell 98 process. I'm not
saying that we made the right decision then, but here's a link to (a
part of)
for MonadZero)
Simon
| -Original Message-
| From: [EMAIL PROTECTED]
| [mailto:[EMAIL PROTECTED] On Behalf Of Simon Peyton-Jones
| Sent: 05 January 2006 09:06
| To: Cale Gibbard; Haskell Mailing List
| Subject: RE: [Haskell] A collection of related proposals
| regarding monads
|
|
| | What do
Hi folks
Wolfgang Jeltsch wrote:
Am Mittwoch, 4. Januar 2006 21:54 schrieb Cale Gibbard:
I personally feel that the inclusion of 'fail' in the Monad class is
an ugly solution to the problem of pattern matching, and gives the
incorrect impression that monads should have some builtin notion
I personally feel that the inclusion of 'fail' in the Monad class is
an ugly solution to the problem of pattern matching, and gives the
incorrect impression that monads should have some builtin notion of
failure. Indeed, it's becoming common to type the result of some
function in an arbitrary
G'day Cale.
Quoting Cale Gibbard [EMAIL PROTECTED]:
I personally feel that the inclusion of 'fail' in the Monad class is
an ugly solution to the problem of pattern matching, and gives the
incorrect impression that monads should have some builtin notion of
failure.
So do I.
We ought to be
Am Mittwoch, 4. Januar 2006 21:54 schrieb Cale Gibbard:
I personally feel that the inclusion of 'fail' in the Monad class is
an ugly solution to the problem of pattern matching, and gives the
incorrect impression that monads should have some builtin notion of
failure.
I totally agree!
[...]
On 04/01/06, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote:
G'day Cale.
Quoting Cale Gibbard [EMAIL PROTECTED]:
I personally feel that the inclusion of 'fail' in the Monad class is
an ugly solution to the problem of pattern matching, and gives the
incorrect impression that monads should have
Am Mittwoch, 4. Januar 2006 22:30 schrieb [EMAIL PROTECTED]:
[...]
Though possible mchoose might be more appropriate.
These leading m's are not nice in my opinion.
Even more appropriate might be to rationalise some of these naming
conventions.
Yes, we should remove those m's and use
G'day all.
I wrote:
My feeling is that do { p - xs; return e } should behave identically
(modulo the precise error message if the pattern match fails) to
map (\p - e) xs. Your proposal would make it into a map/filter
hybrid.
Which, of course, it is now. I blame lack of caffeine.
Cale Gibbard writes:
I personally feel that the inclusion of 'fail' in the Monad class is
an ugly solution to the problem of pattern matching, and gives the
incorrect impression that monads should have some builtin notion of
failure. Indeed, it's becoming common to type the result of some
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