On Thu, Feb 23, 2017 at 1:10 AM, <beginners-request@haskell.org> wrote:

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Today's Topics:

1. Re: Type error when using splitOn function. (Francesco Ariis)
2. Re: Type error when using splitOn function. (S. H. Aegis)
3. How to link two Types (PICCA Frederic-Emmanuel)
4. Re: How to link two Types (David McBride)
5. Re: How to link two Types (PICCA Frederic-Emmanuel)
6. Re: How to link two Types (David McBride)

----------------------------------------------------------------------

Message: 1
Date: Wed, 22 Feb 2017 14:31:16 +0100
From: Francesco Ariis <fa-ml@ariis.it>
To: beginners@haskell.org
Subject: Re: [Haskell-beginners] Type error when using splitOn
function.
Message-ID: <20170222133116.GA14860@casa.casa>
Content-Type: text/plain; charset=us-ascii

On Wed, Feb 22, 2017 at 09:02:22PM +0900, S. H. Aegis wrote:
> Thank you so much.
>
> --makeRxDxList :: Functor f => f Text -> f [Text]
> Above signature comes from ghci using command :t
> My intention is
> makeRxDxList :: Text -> [[Text]]
> but, I got error, and try several times and below codes pass a complier.
> makeRxDxList rowRxDx = fmap (\x -> splitOn (pack ",") x) rowRxDx -- This
> code pass a compile.
> and then, I run ghci, type :t, and got below signature.
> makeRxDxList :: Functor f => f Text -> f [Text]
>
> Your kind answer says, I cannot help using fmap. right? ^^;
> Thanks again.

Then this:

makeRxDxList :: Text -> [[Text]]
makeRxDxList rowRxDx = fmap f (lines rowRxDx)
-- you imported Prelude hiding map, so we will use fmap
where
f :: Text -> [Text]
f x = splitOn (pack ",") x

should do (at least it typechecks).

GHC errors may not have the prettiest formatting ever, but they are
very useful, the most important bits being line & column of the offending
expression plus the "expected this but got that" part; get acquainted
with them!

------------------------------

Message: 2
Date: Wed, 22 Feb 2017 22:41:10 +0900
From: "S. H. Aegis" <shaegis@gmail.com>
To: The Haskell-Beginners Mailing List - Discussion of primarily
beginner-level topics related to Haskell <beginners@haskell.org>
Subject: Re: [Haskell-beginners] Type error when using splitOn
function.
Message-ID:
<CAJp-NqxZ5gAqQT8-Swd+PE-ys_PVSAJo1c74+B-UuFabJr_F4w@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

It works !!! (^O^)
Thank you so much.

Have a nice day~!

2017-02-22 22:31 GMT+09:00 Francesco Ariis <fa-ml@ariis.it>:

> On Wed, Feb 22, 2017 at 09:02:22PM +0900, S. H. Aegis wrote:
> > Thank you so much.
> >
> > --makeRxDxList :: Functor f => f Text -> f [Text]
> > Above signature comes from ghci using command :t
> > My intention is
> > makeRxDxList :: Text -> [[Text]]
> > but, I got error, and try several times and below codes pass a complier.
> > makeRxDxList rowRxDx = fmap (\x -> splitOn (pack ",") x) rowRxDx -- This
> > code pass a compile.
> > and then, I run ghci, type :t, and got below signature.
> > makeRxDxList :: Functor f => f Text -> f [Text]
> >
> > Your kind answer says, I cannot help using fmap. right? ^^;
> > Thanks again.
>
> Then this:
>
> makeRxDxList :: Text -> [[Text]]
> makeRxDxList rowRxDx = fmap f (lines rowRxDx)
> -- you imported Prelude hiding map, so we will use fmap
> where
> f :: Text -> [Text]
> f x = splitOn (pack ",") x
>
> should do (at least it typechecks).
>
> GHC errors may not have the prettiest formatting ever, but they are
> very useful, the most important bits being line & column of the offending
> expression plus the "expected this but got that" part; get acquainted
> with them!
>
> _______________________________________________
> Beginners mailing list
> Beginners@haskell.org
> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>

--
Sok Ha, CHANG
Dr. Chang's Clinic. #203. 503-23. AmSa-Dong, GangDong-Gu, Seoul.
Tel: +82-2-442-7585
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Message: 3
Date: Wed, 22 Feb 2017 15:27:39 +0000
From: PICCA Frederic-Emmanuel
<frederic-emmanuel.picca@synchrotron-soleil.fr>
To: "Beginners@haskell.org" <Beginners@haskell.org>
Subject: [Haskell-beginners] How to link two Types
Message-ID:
<A2A20EC3B8560D408356CAC2FC148E53BB34799C@SUN-DAG3.synchrotron-soleil.fr>

Content-Type: text/plain; charset="us-ascii"

Hello, I wrote this code

data DataFrameH5 a
= DataFrameH5
(Nxs a) -- Nexus file
(DataSource H5) -- gamma
(DataSource H5) -- delta
(DataSource H5) -- wavelength
PoniGenerator -- ponie generator

class Frame t a where
len :: t -> IO (Maybe Int)
row :: t -> Int -> MaybeT IO (DifTomoFrame a DIM1)

instance Frame (DataFrameH5 DataFrameH5Path) DataFrameH5Path where
len (DataFrameH5 _ _ (DataSourceH5 _ d) _ _) = lenH5Dataspace d

row d@(DataFrameH5 nxs' g d' w ponigen) idx = do
n <- lift $ len d
let eof = fromJust n - 1 == idx
let mu = 0.0
let komega = 0.0
let kappa = 0.0
let kphi = 0.0
gamma <- g `atIndex'` (ix1 0)
delta <- d' `atIndex'` (ix1 idx)
wavelength <- w `atIndex'` (ix1 0)
let source = Source (head wavelength *~ nano meter)
let positions = concat [mu, komega, kappa, kphi, gamma, delta]
-- print positions
let geometry = Geometry K6c source positions Nothing
let detector = ZeroD
m <- lift $ geometryDetectorRotationGet geometry detector
poniext <- lift $ ponigen (MyMatrix HklB m) idx
return $ DifTomoFrame { difTomoFrameNxs = nxs'
, difTomoFrameIdx = idx
, difTomoFrameEOF = eof
, difTomoFrameGeometry = geometry
, difTomoFramePoniExt = poniext
}

has you can see my t type contains also the a reference to the a one
So when I create the instance, I need to write two times the DataFrameH5Path

I would like to know how to write the same class with only

class Frame t where
len :: t -> IO (Maybe Int)
row :: t -> Int -> MaybeT IO (DifTomoFrame <extract type a from type t> DIM1)

thanks for your help

Frederic

------------------------------

Message: 4
Date: Wed, 22 Feb 2017 10:59:38 -0500
From: David McBride <toad3k@gmail.com>
To: The Haskell-Beginners Mailing List - Discussion of primarily
beginner-level topics related to Haskell <beginners@haskell.org>
Subject: Re: [Haskell-beginners] How to link two Types
Message-ID:
<CAN+Tr42Bu7nENuGLkBuU9q4Jrdzd-3qoA+G-b+AWh-N-MQzDsw@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8

Maybe TypeFamilies would work for you? I can only give you a
barebones outline of what it might look like.

{-# LANGUAGE MultiParamTypeClasses, FlexibleInstances, TypeFamilies #-}
import Control.Monad.Trans.Maybe

data DataFrameH5 a = DataFrameH5
data DataFrameH5Path = DataFrameH5Path

class Frame t where
type Key t
len :: t -> IO (Maybe Int)
row :: t -> Int -> MaybeT IO (Key t)

instance Frame (DataFrameH5 a) where
type Key (DataFrameH5 a) = a
len DataFrameH5 = return . Just $ undefined
row DataFrameH5 idx = MaybeT $ do
return undefined

On Wed, Feb 22, 2017 at 10:27 AM, PICCA Frederic-Emmanuel
<frederic-emmanuel.picca@synchrotron-soleil.fr> wrote:
> Hello, I wrote this code
>
> data DataFrameH5 a
> = DataFrameH5
> (Nxs a) -- Nexus file
> (DataSource H5) -- gamma
> (DataSource H5) -- delta
> (DataSource H5) -- wavelength
> PoniGenerator -- ponie generator
>
> class Frame t a where
> len :: t -> IO (Maybe Int)
> row :: t -> Int -> MaybeT IO (DifTomoFrame a DIM1)
>
> instance Frame (DataFrameH5 DataFrameH5Path) DataFrameH5Path where
> len (DataFrameH5 _ _ (DataSourceH5 _ d) _ _) = lenH5Dataspace d
>
> row d@(DataFrameH5 nxs' g d' w ponigen) idx = do
> n <- lift $ len d
> let eof = fromJust n - 1 == idx
> let mu = 0.0
> let komega = 0.0
> let kappa = 0.0
> let kphi = 0.0
> gamma <- g `atIndex'` (ix1 0)
> delta <- d' `atIndex'` (ix1 idx)
> wavelength <- w `atIndex'` (ix1 0)
> let source = Source (head wavelength *~ nano meter)
> let positions = concat [mu, komega, kappa, kphi, gamma, delta]
> -- print positions
> let geometry = Geometry K6c source positions Nothing
> let detector = ZeroD
> m <- lift $ geometryDetectorRotationGet geometry detector
> poniext <- lift $ ponigen (MyMatrix HklB m) idx
> return $ DifTomoFrame { difTomoFrameNxs = nxs'
> , difTomoFrameIdx = idx
> , difTomoFrameEOF = eof
> , difTomoFrameGeometry = geometry
> , difTomoFramePoniExt = poniext
> }
>
> has you can see my t type contains also the a reference to the a one
> So when I create the instance, I need to write two times the DataFrameH5Path
>
> I would like to know how to write the same class with only
>
> class Frame t where
> len :: t -> IO (Maybe Int)
> row :: t -> Int -> MaybeT IO (DifTomoFrame <extract type a from type t> DIM1)
>
> thanks for your help
>
> Frederic
> _______________________________________________
> Beginners mailing list
> Beginners@haskell.org
> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

------------------------------

Message: 5
Date: Wed, 22 Feb 2017 16:19:41 +0000
From: PICCA Frederic-Emmanuel
<frederic-emmanuel.picca@synchrotron-soleil.fr>
To: "The Haskell-Beginners Mailing List - Discussion of primarily
beginner-level topics related to Haskell" <beginners@haskell.org>
Subject: Re: [Haskell-beginners] How to link two Types
Message-ID:
<A2A20EC3B8560D408356CAC2FC148E53BB3489ED@SUN-DAG3.synchrotron-soleil.fr>

Content-Type: text/plain; charset="us-ascii"

Hello thanks, I will investigate, but I like this solution.
I can ad more type to a type family right ?

Is it possible with this type family to be able to link in the other way ?

a -> t

Cheers

Fred

------------------------------

Message: 6
Date: Wed, 22 Feb 2017 11:29:16 -0500
From: David McBride <toad3k@gmail.com>
To: The Haskell-Beginners Mailing List - Discussion of primarily
beginner-level topics related to Haskell <beginners@haskell.org>
Subject: Re: [Haskell-beginners] How to link two Types
Message-ID:
<CAN+Tr43H_Z9ckhW+f6GqeBXf_O=LX=AvQYgzCh7gx7Qyxeb4dg@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8

It is hard to tell from your code what you intend, but it works
however you want it to, so long as it type checks.

class Frame a where
type Whatever a
len :: Whatever a -> IO (Maybe Int)
row :: Whatever a -> MaybeT IO (DifTomoFrame a DIM1)

instance Frame DataFrameH5Path where
type Whatever DataFrameH5Path = DataFrameH5
len = undefined -- :: DataFrameH5 -> IO (Maybe Int)
row = undefined -- :: DataFrameH5 -> Int -> MaybeT (DifTomoFrame
DataFrameH5Path DIM1)

On Wed, Feb 22, 2017 at 11:19 AM, PICCA Frederic-Emmanuel
<frederic-emmanuel.picca@synchrotron-soleil.fr> wrote:
> Hello thanks, I will investigate, but I like this solution.
> I can ad more type to a type family right ?
>
>
> Is it possible with this type family to be able to link in the other way ?
>
> a -> t
>
> Cheers
>
> Fred
> _______________________________________________
> Beginners mailing list
> Beginners@haskell.org
> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

------------------------------

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