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Today's Topics:
1. http-conduit: Changelogs/notes on API changes (Sevcsik Andr?s)
2. Re: ghc-mod and cabal "could not find module Prelude"
(Alan Buxton)
3. Functor fmap: how to (Imants Cekusins)
4. Re: http-conduit: Changelogs/notes on API changes
(Henk-Jan van Tuyl)
----------------------------------------------------------------------
Message: 1
Date: Wed, 24 Jun 2015 14:53:42 +0000
From: Sevcsik Andr?s <[email protected]>
To: "[email protected]" <[email protected]>
Subject: [Haskell-beginners] http-conduit: Changelogs/notes on API
changes
Message-ID:
<cac+tgn6gp7j4t+ej0fp-qxwyyfmarp2ryav2j_aa3vozrpw...@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"
Hi,
I'm trying to update the couchdb-conduit package to use the latest
(stackage) version of it's dependencies.
Is there any changelog, release notes, or even a blogpost which summarise
how the API was changed between different major versions?
And in general, is there a common practice for hackage packages on how are
API-breaking changes are communicated?
Cheers
--
Minden j?t,
Sevcsik Andr?s
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Message: 2
Date: Wed, 24 Jun 2015 15:56:23 +0100
From: "Alan Buxton" <[email protected]>
To: "'The Haskell-Beginners Mailing List - Discussion of primarily
beginner-level topics related to Haskell'" <[email protected]>
Subject: Re: [Haskell-beginners] ghc-mod and cabal "could not find
module Prelude"
Message-ID: <[email protected]>
Content-Type: text/plain; charset="utf-8"
Hi all
Thanks for the help you gave me on and off list. I wanted to let you know the
solution in the end. The issue rested on the old version of cabal that I had
(1.16). I had to install a newer version of cabal, but not 1.22, so using:
cabal install cabal-install --constraint "Cabal <1.22"
The gotcha here is that I had to then adjust my path so that the local
~/.cabal/bin directory comes first in the $PATH to ensure my local cabal was
being used.
All the best
Alan
From: Alan Buxton [mailto:[email protected]]
Sent: 23 June 2015 18:47
To: 'The Haskell-Beginners Mailing List - Discussion of primarily
beginner-level topics related to Haskell'
Subject: RE: [Haskell-beginners] ghc-mod and cabal "could not find module
Prelude"
Thanks for the suggestions:
Imants:
There is
library
build-depends: base ==4.6.*
(The cabal file was generated by cabal init and so I would hope it's legit :))
I installed Haskell on my Ubuntu just by doing sudo apt-get install
haskell-platform.
Interestingly, if I do use ghc-mod on a real file with some errors in I get
unnecessarily verbose error messages similar to described here:
http://mail.haskell.org/pipermail/beginners/2015-February/014573.html I wonder
if the issues are related somehow?
Norbert:
I?m not sure what exactly you are suggesting but if I even take the version
constraint out of the cabal file so I have build-depends: base (without any
version specified) then I get the same issue.
From: Beginners [mailto:[email protected]] On Behalf Of Norbert
Melzer
Sent: 23 June 2015 17:49
To: The Haskell-Beginners Mailing List - Discussion of primarily beginner-level
topics related to Haskell
Subject: Re: [Haskell-beginners] ghc-mod and cabal "could not find module
Prelude"
Just add base as dependency in the version constraints matching that base that
is delivered with your version of GHC.
Alan Buxton <[email protected] <mailto:[email protected]> > schrieb am
Di., 23.06.2015, 16:48:
Hi
I?ve recently set up a new Haskell working environment on Ubuntu 14.04. I
installed the Ubuntu packaged version of Haskell platform.
My problem is that I can?t now get ghc-mod check to work if there is a cabal
file in the current directory.
I am using:
* ghc-mod 5.2.1.2 compiled by GHC 7.6.3
* cabal 1.16.0.2
See below an extract of trying to run ghc-mod check in a directory that was
empty until I just ran cabal init in it:
~/tmp-ghc-mod$ ls
Setup.hs tmp-ghc-mod.cabal
~/tmp-ghc-mod$ ghc-mod check Setup.hs
Setup.hs:1:1:Could not find module `Prelude'It is a member of the hidden
package `base'.Perhaps you need to add `base' to the build-depends in your
.cabal file.It is a member of the hidden package `haskell98-2.0.0.2'.Perhaps
you need to add `haskell98' to the build-depends in your .cabal file.It is a
member of the hidden package `haskell2010-1.1.1.0'.Perhaps you need to add
`haskell2010' to the build-depends in your .cabal file.Use -v to see a list of
the files searched for.
~/tmp-ghc-mod$ mv tmp-ghc-mod.cabal tmp-ghc-mod.cabal.NOT
~/tmp-ghc-mod$ ls
dist Setup.hs tmp-ghc-mod.cabal.NOT
~/tmp-ghc-mod$ ghc-mod check Setup.hs
Setup.hs:2:1:Warning: Top-level binding with no type signature: main :: IO ()
~/tmp-ghc-mod$
So? ghc-mod behaves as expected when there is no cabal file, but doesn?t behave
as expected if there is a cabal file.
My google fu isn?t helping me out on this: the only issues I have seen are to
do with a change in format of the cabal file in newer versions of cabal.
Any ideas?
Thanks
Alan
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Message: 3
Date: Wed, 24 Jun 2015 21:52:37 +0200
From: Imants Cekusins <[email protected]>
To: The Haskell-Beginners Mailing List - Discussion of primarily
beginner-level topics related to Haskell <[email protected]>
Subject: [Haskell-beginners] Functor fmap: how to
Message-ID:
<cap1qinzyxpq-cj-70b46knwmo5gnqofqtp8w_ttzyzksj1g...@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
There are a few Functor & fmap tutorials. Here is basic use of fmap.
If it leaves you confused, please ignore it.
module FunctorFmap where
{-
why maybe & list?
Functor instances exist for Maybe & List
http://hackage.haskell.org/package/base-4.8.0.0/docs/Data-Functor.html#t:Functor
expand "instances"
-}
-- (a -> b)
add3:: Int -> Int
add3 = (+ 3)
-- maybe
runMaybe::IO ()
runMaybe = do
print $ maybeFmap $ Just 1
print $ maybeInfixed $ Just 1
print $ maybeFmap Nothing
print $ maybeInfixed Nothing
-- maybeFmap & maybeInfixed do the same thing. different syntax
maybeFmap::Maybe Int -> Maybe Int
maybeFmap = fmap add3
maybeInfixed::Maybe Int -> Maybe Int
maybeInfixed mi = add3 <$> mi
-- list
runList::IO ()
runList = do
print $ listFmap [1,2]
print $ listInfixed [1,2]
-- listFmap & listInfixed do the same thing. different syntax
listFmap::[Int] -> [Int]
listFmap = fmap add3
listInfixed::[Int] -> [Int]
listInfixed l = add3 <$> l
------------------------------
Message: 4
Date: Wed, 24 Jun 2015 22:43:23 +0200
From: "Henk-Jan van Tuyl" <[email protected]>
To: "[email protected]" <[email protected]>, Sevcsik Andr?s
<[email protected]>
Subject: Re: [Haskell-beginners] http-conduit: Changelogs/notes on API
changes
Message-ID: <op.x0q46ly1pz0j5l@alquantor>
Content-Type: text/plain; charset=iso-8859-15; format=flowed;
delsp=yes
On Wed, 24 Jun 2015 16:53:42 +0200, Sevcsik Andr?s <[email protected]>
wrote:
> Hi,
>
> I'm trying to update the couchdb-conduit package to use the latest
> (stackage) version of it's dependencies.
>
> Is there any changelog, release notes, or even a blogpost which summarise
> how the API was changed between different major versions?
You can get all change info from the GitHub network graph; hovering over
the dots give short description of the changes, click on the dots shows
all details:
https://github.com/akaspin/couchdb-conduit/network
(it is however not clear to me, which version is stored on Hackage)
> And in general, is there a common practice for hackage packages on how
> are
> API-breaking changes are communicated?
The version of the package gives some indication, see the Package
Versioning Policy,
https://wiki.haskell.org/Package_versioning_policy#Version_numbers
Regards,
Henk-Jan van Tuyl
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