7;cast' divBy to List, Identity, other
monads? How?
On 6/6/07, Tillmann Rendel <[EMAIL PROTECTED]> wrote:
Dmitri O.Kondratiev wrote:
> Monad class contains declaration
>
> *fail* :: String -> m a
>
> and provides default implementation for 'fail' as
Monad class contains declaration
*fail* :: String -> m a
and provides default implementation for 'fail' as:
fail s = error s
On the other hand Prelude defines:
*
error* :: String -> a
which stops execution and displays an error message.
Questions:
1) What value and type 'error' actually retu
(dig <:> (dig <:> succeed []))) ~~> [("123", "")]
(dig <:> (dig <:> (dig <:> (dig <:> pList dig ~~> []
the last one returns [] because:
(dig >*> dig >*> dig >*> dig) "123" ~~> []
As a result we get:
[(&
((p >*> pList p) `build` (uncurry (:)))
comp1 = dig >*> dig
comp2 = dig >*> (succeed [])
pl1 = comp2 `build` (uncurry (:))
test = pList dig
On 3/28/07, Daniel Fischer <[EMAIL PROTECTED]> wrote:
Am Dienstag, 27. März 2007 12:15 schrieb Dmitri O.Kondratiev:
> Th
List p
will be done *before* 'build' will be applied?
Correct?
Thanks,
Dima
On 3/26/07, Daniel Fischer <[EMAIL PROTECTED]> wrote:
> -Ursprüngliche Nachricht-
> Von: "Dmitri O.Kondratiev" <[EMAIL PROTECTED]>
> Gesendet: 26.03.07 16:44:12
> An: h
Please see my questions inside comments {-- --} :
Thanks!
---
module Parser where
import Data.Char
type Parse a b = [a] -> [(b, [a])]
{--
Newbie: a parser for a list of objects?
I am working with the section 17.5 "Case study: parsing expressions" of the
book "Haskell The Craft of Functional
Now, in the 17.5 section of a book one may see the following declarations:
succeed :: b -> Parse a b
*Before looking at 'succeed' function definition* one may think that
'succeed' is a function of *one* argument of type 'b' that returns object
of
type 'Parse a b'.
That's what it is. Howev
I am learning Haskell working through Simon Thompson book "Haskell The Craft
of Functional Programming" (second edition). Solving problems in the book
with more or less success I arrived almost to the end of the book at the
section 17.5 "Case study: parsing expressions".
Most probably the question
On 2/16/07, Jules Bean <[EMAIL PROTECTED]> wrote:
Actually, lists are partly defined in the Prelude, with auxiliary
functions in Data.List. In particular, <= for List is defined in the
Prelude. Or rather, I should say, the Ord instance for lists is defined
in the prelude (and only if the type in
Going through "Haskell. The Craft of Functional Programming" book , in
section 16.8 I found a Set module example.
Module declarations starts with:
import List hiding (union)
"Set" module here is built with list and uses among other things list
comparison functions such as (==) and (<=).
For exa
ent to f1. (I used different type variables to reduce confusion)
This constraint gives f1 the following type
f1 :: (c -> Maybe d) -> (t -> Maybe c) -> t -> Maybe (Maybe d)
substituting different type variable names gives
f1 :: (b -> Maybe c) -> (a -> Maybe b) -> a -&g
I am trying to solve a problem from "The Craft of Functional Programming" book:
14.38 ... define the function:
data Maybe a = Nothing | Just a
composeMaybe :: (a -> Maybe b) -> (b -> Maybe c) -> (a -> Maybe c)
using functions:
squashMaybe :: Maybe (Maybe a) -> Maybe a
squashMaybe (Just (Just x)
On 7/25/06, Jared Updike <[EMAIL PROTECTED]> wrote:
> I am trying to derive MyOrd class from Eq (Prelude):
>
> class Eq a => MyOrd a where
> (%<=), (%>), (%>=) :: a -> a -> Bool
> x %<= y = (x < y || x == y)
> x %> y = y < x
> x %>= y = (y < x || x == y)
>
> Q: Wh
I am trying to derive MyOrd class from Eq (Prelude):
class Eq a => MyOrd a where
(%<=), (%>), (%>=) :: a -> a -> Bool
x %<= y = (x < y || x == y)
x %> y = y < x
x %>= y = (y < x || x == y)
I get these errors:
ClassTest.hs:28:21:
Could not deduce (Ord a) from the
Hi Neil,
Thanks for your reply.
Starting from YHC porting pages the only source for Win32 port I
found is WinHaskell.
[http://www-users.cs.york.ac.uk/~ndm/projects/winhaskell.php]
I have not yet found which port it is: Hugs, YHc, ...?
Also there is a thing called WinHugs at
http://www-users.cs.y
I am sorry for confusion that abreviation PPC may cause in the text of
my message. In this context I used 'PPC' to refer to Pocket PC and
nothing else.
Sorry again.
On 3/31/06, Dmitri O.Kondratiev <[EMAIL PROTECTED]> wrote:
> Any ideas on how much work needs to be done for u
Any ideas on how much work needs to be done for using Haskell on PPC
Windows Mobile platform?
It would be interesting to use PPC as:
1) Haskell learning tool, so small code snipets could be entered and
run directly on hand-held (REPL). How hard is it to port Hugs to PPC
for this? Do any other (then
101 - 117 of 117 matches
Mail list logo
