Proposal: give a field name to Data.Ord.Down - Libraries - Haskell.org

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Proposal: give a field name to Data.Ord.Down

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Fumiaki Kinoshita

2 May 2019 2 May '19

10:56 p.m.

It's awkward to write a lambda to unwrap this kind of wrappers. I propose newtype Down a = Down { getDown :: a } with the Show/Read instances as if they didn't have named fields. The same goes for Control.Arrow.ArrowMonad, although I'm not sure about its usefulness...

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davean

2 May 2 May

11:13 p.m.

I have needed this many times. On Thu, May 2, 2019 at 10:56 PM Fumiaki Kinoshita wrote:

It's awkward to write a lambda to unwrap this kind of wrappers. I propose

newtype Down a = Down { getDown :: a }

with the Show/Read instances as if they didn't have named fields.

The same goes for Control.Arrow.ArrowMonad, although I'm not sure about its usefulness... _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

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Theodore Lief Gannon

3 May 3 May

2:39 p.m.

I just added `Down` to the RIO prelude, and the absence of a deconstructor was my #1 concern about doing so. It invites another package to provide an alternative, and we avoid including things with actively competing implementations. I'd much rather see this handled in `base`. (I'd rather have it named `unDown`, so as not to steal the name `getDown` from the heroes who will pair it with `getFunky`. But that's a lesser concern.) On Thu, May 2, 2019 at 8:13 PM davean wrote:

I have needed this many times.

On Thu, May 2, 2019 at 10:56 PM Fumiaki Kinoshita wrote:

...
It's awkward to write a lambda to unwrap this kind of wrappers. I propose

newtype Down a = Down { getDown :: a }

with the Show/Read instances as if they didn't have named fields.

The same goes for Control.Arrow.ArrowMonad, although I'm not sure about its usefulness... _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

_______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

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Edward Kmett

4 May 4 May

3:28 a.m.

+1 from me, with no preference between getDown and runDown -Edward

On May 3, 2019, at 1:13 PM, davean wrote:

I have needed this many times.

...
On Thu, May 2, 2019 at 10:56 PM Fumiaki Kinoshita wrote: It's awkward to write a lambda to unwrap this kind of wrappers. I propose

newtype Down a = Down { getDown :: a }

with the Show/Read instances as if they didn't have named fields.

The same goes for Control.Arrow.ArrowMonad, although I'm not sure about its usefulness... _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

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Zemyla

4:16 a.m.

+1 from me, but the field name should be "up". On Sat, May 4, 2019, 02:29 Edward Kmett wrote:

+1 from me, with no preference between getDown and runDown

-Edward

On May 3, 2019, at 1:13 PM, davean wrote:

I have needed this many times.

On Thu, May 2, 2019 at 10:56 PM Fumiaki Kinoshita wrote:

...
It's awkward to write a lambda to unwrap this kind of wrappers. I propose

newtype Down a = Down { getDown :: a }

with the Show/Read instances as if they didn't have named fields.

The same goes for Control.Arrow.ArrowMonad, although I'm not sure about its usefulness... _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

_______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

_______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

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Elliot Cameron

10:08 a.m.

I can getDown with this. +1 On Sat, May 4, 2019, 4:17 AM Zemyla wrote:

+1 from me, but the field name should be "up".

On Sat, May 4, 2019, 02:29 Edward Kmett wrote:

...
+1 from me, with no preference between getDown and runDown

-Edward

On May 3, 2019, at 1:13 PM, davean wrote:

I have needed this many times.

On Thu, May 2, 2019 at 10:56 PM Fumiaki Kinoshita wrote:

...
It's awkward to write a lambda to unwrap this kind of wrappers. I propose

newtype Down a = Down { getDown :: a }

with the Show/Read instances as if they didn't have named fields.

The same goes for Control.Arrow.ArrowMonad, although I'm not sure about its usefulness... _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

_______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

_______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

_______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

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Carter Schonwald

2:11 p.m.

+1 On Sat, May 4, 2019 at 10:08 AM Elliot Cameron wrote:

I can getDown with this. +1

On Sat, May 4, 2019, 4:17 AM Zemyla wrote:

...
+1 from me, but the field name should be "up".

On Sat, May 4, 2019, 02:29 Edward Kmett wrote:

...
+1 from me, with no preference between getDown and runDown

-Edward

On May 3, 2019, at 1:13 PM, davean wrote:

I have needed this many times.

On Thu, May 2, 2019 at 10:56 PM Fumiaki Kinoshita wrote:

...
It's awkward to write a lambda to unwrap this kind of wrappers. I propose

newtype Down a = Down { getDown :: a }

with the Show/Read instances as if they didn't have named fields.

The same goes for Control.Arrow.ArrowMonad, although I'm not sure about its usefulness... _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

_______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

_______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

_______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

_______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

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chessai .

4:20 p.m.

+1 On Thu, May 2, 2019, 10:56 PM Fumiaki Kinoshita wrote:

It's awkward to write a lambda to unwrap this kind of wrappers. I propose

newtype Down a = Down { getDown :: a }

with the Show/Read instances as if they didn't have named fields.

The same goes for Control.Arrow.ArrowMonad, although I'm not sure about its usefulness... _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

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George Wilson

9:49 p.m.

+1 On Sun., 5 May 2019, 06:21 chessai ., wrote:

+1

On Thu, May 2, 2019, 10:56 PM Fumiaki Kinoshita wrote:

...
It's awkward to write a lambda to unwrap this kind of wrappers. I propose

newtype Down a = Down { getDown :: a }

with the Show/Read instances as if they didn't have named fields.

The same goes for Control.Arrow.ArrowMonad, although I'm not sure about its usefulness... _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

_______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

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Andrew Martin

5 May 5 May

2:11 p.m.

+1. I do prefer getDown as the field name, but anything is better than nothing. Sent from my iPhone

On May 4, 2019, at 9:49 PM, George Wilson wrote:

+1

...
On Sun., 5 May 2019, 06:21 chessai ., wrote: +1

...
On Thu, May 2, 2019, 10:56 PM Fumiaki Kinoshita wrote: It's awkward to write a lambda to unwrap this kind of wrappers. I propose

newtype Down a = Down { getDown :: a }

with the Show/Read instances as if they didn't have named fields.

The same goes for Control.Arrow.ArrowMonad, although I'm not sure about its usefulness... _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

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participants (10)

Andrew Martin
Carter Schonwald
chessai .
davean
Edward Kmett
Elliot Cameron
Fumiaki Kinoshita
George Wilson
Theodore Lief Gannon
Zemyla