Proposal: Add (<$>) to Prelude as part of the AMP in GHC 7.10-RC3

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Proposal: Add (<$>) to Prelude as part of the AMP in GHC 7.10-RC3

Edward Kmett-2
We have a couple of weeks until the third release candidate for GHC 7.10 goes out the door.

Along the way with the last couple of release candidates folks have found some problems with the way we implemented the AMP. [1][2]

Most notably, we failed to include (<$>) in the Prelude, so the standard idiom of

foo <$> bar <*> baz <*> quux

doesn't work out of the box!

I'd like to include (<$>) in the Prelude in RC3.

I'd also like to invite discussion about whether folks believe we should include (<$) out of the box. 

(<$) has been a member of Functor for a long time, which is only visible if you import it from Data.Functor or bring in Control.Applicative. There is an idiom that you use (<*) and (<$) to point to the parts of the structure that you want to keep the answers from when building longer such Applicative chains.

Discussion Period: 2 weeks

Thank you,
-Edward Kmett


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Re: Proposal: Add (<$>) to Prelude as part of the AMP in GHC 7.10-RC3

Michael Snoyman
+1 on <$>
+1 on <$

On Tue Feb 24 2015 at 5:39:56 PM Edward Kmett <[hidden email]> wrote:
We have a couple of weeks until the third release candidate for GHC 7.10 goes out the door.

Along the way with the last couple of release candidates folks have found some problems with the way we implemented the AMP. [1][2]

Most notably, we failed to include (<$>) in the Prelude, so the standard idiom of

foo <$> bar <*> baz <*> quux

doesn't work out of the box!

I'd like to include (<$>) in the Prelude in RC3.

I'd also like to invite discussion about whether folks believe we should include (<$) out of the box. 

(<$) has been a member of Functor for a long time, which is only visible if you import it from Data.Functor or bring in Control.Applicative. There is an idiom that you use (<*) and (<$) to point to the parts of the structure that you want to keep the answers from when building longer such Applicative chains.

Discussion Period: 2 weeks

Thank you,
-Edward Kmett

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Re: Proposal: Add (<$>) to Prelude as part of the AMP in GHC 7.10-RC3

Alec

On Tue Feb 24 2015 at 10:42:41 AM Michael Snoyman <[hidden email]> wrote:
+1 on <$>
+1 on <$

On Tue Feb 24 2015 at 5:39:56 PM Edward Kmett <[hidden email]> wrote:
We have a couple of weeks until the third release candidate for GHC 7.10 goes out the door.

Along the way with the last couple of release candidates folks have found some problems with the way we implemented the AMP. [1][2]

Most notably, we failed to include (<$>) in the Prelude, so the standard idiom of

foo <$> bar <*> baz <*> quux

doesn't work out of the box!

I'd like to include (<$>) in the Prelude in RC3.

I'd also like to invite discussion about whether folks believe we should include (<$) out of the box. 

(<$) has been a member of Functor for a long time, which is only visible if you import it from Data.Functor or bring in Control.Applicative. There is an idiom that you use (<*) and (<$) to point to the parts of the structure that you want to keep the answers from when building longer such Applicative chains.

Discussion Period: 2 weeks

Thank you,
-Edward Kmett

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Re: Proposal: Add (<$>) to Prelude as part of the AMP in GHC 7.10-RC3

David Feuer
In reply to this post by Edward Kmett-2

+1 on <$>. No opinion on <$. Does that mean I can an an extra +1 for <$>?

On Feb 24, 2015 10:39 AM, "Edward Kmett" <[hidden email]> wrote:
We have a couple of weeks until the third release candidate for GHC 7.10 goes out the door.

Along the way with the last couple of release candidates folks have found some problems with the way we implemented the AMP. [1][2]

Most notably, we failed to include (<$>) in the Prelude, so the standard idiom of

foo <$> bar <*> baz <*> quux

doesn't work out of the box!

I'd like to include (<$>) in the Prelude in RC3.

I'd also like to invite discussion about whether folks believe we should include (<$) out of the box. 

(<$) has been a member of Functor for a long time, which is only visible if you import it from Data.Functor or bring in Control.Applicative. There is an idiom that you use (<*) and (<$) to point to the parts of the structure that you want to keep the answers from when building longer such Applicative chains.

Discussion Period: 2 weeks

Thank you,
-Edward Kmett


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Re: Proposal: Add (<$>) to Prelude as part of the AMP in GHC 7.10-RC3

Christopher Reichert
In reply to this post by Edward Kmett-2

+1 on <$>. Indifferent on <$.

-Christopher

On Tue, Feb 24 2015, Edward Kmett <[hidden email]> wrote:

> We have a couple of weeks until the third release candidate for GHC 7.10
> goes out the door.
>
> Along the way with the last couple of release candidates folks have found
> some problems with the way we implemented the AMP. [1][2]
>
> Most notably, we failed to include (<$>) in the Prelude, so the standard
> idiom of
>
> foo <$> bar <*> baz <*> quux
>
> doesn't work out of the box!
>
> I'd like to include (<$>) in the Prelude in RC3.
>
> I'd also like to invite discussion about whether folks believe we should
> include (<$) out of the box.
>
> (<$) has been a member of Functor for a long time, which is only visible if
> you import it from Data.Functor or bring in Control.Applicative. There is
> an idiom that you use (<*) and (<$) to point to the parts of the structure
> that you want to keep the answers from when building longer such
> Applicative chains.
>
> Discussion Period: 2 weeks
>
> Thank you,
> -Edward Kmett
>
> [1] http://www.reddit.com/r/haskell/comments/2wzixa/shouldnt_be_in_prelude/
> [2] https://plus.google.com/115504368969270249241/posts/URzeDWd7qMp
> _______________________________________________
> Libraries mailing list
> [hidden email]
> http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries
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Re: Proposal: Add (<$>) to Prelude as part of the AMP in GHC 7.10-RC3

Joachim Breitner-2
In reply to this post by Edward Kmett-2
Hi,


Am Dienstag, den 24.02.2015, 10:39 -0500 schrieb Edward Kmett:

> I'd like to include (<$>) in the Prelude in RC3.

+1
>
> I'd also like to invite discussion about whether folks believe we
> should include (<$) out of the box.
>
not sure that it’s worth having it in the Prelude. So my default for
changes that I’m not convinced about (especially if they affect the
Prelude):

-1

Greetings,
Joachim


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Re: Proposal: Add (<$>) to Prelude as part of the AMP in GHC 7.10-RC3

Herbert Valerio Riedel
In reply to this post by Edward Kmett-2
On 2015-02-24 at 16:39:51 +0100, Edward Kmett wrote:

[...]

> I'd like to include (<$>) in the Prelude in RC3.
>
> I'd also like to invite discussion about whether folks believe we should
> include (<$) out of the box.

+1 for <$>
+0.99999... for <$

PS: ...and there's also a ticket for this at
    https://ghc.haskell.org/trac/ghc/ticket/10113

The linked Phabricator code-revision D680 currently just re-exports
(<$>), I'll soon create a 2nd one which also exports (<$)

Cheers,
  hvr
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Re: Proposal: Add (<$>) to Prelude as part of the AMP in GHC 7.10-RC3

Greg Fitzgerald
In reply to this post by Alec
-1 on both.  Leaving them out might encourage people to use "pure foo"
or the idiom QuasiQuoter.  It's not obvious [to me at least] which of
the 3 styles is best, so I'd prefer to keep the additional syntax out
of the Prelude.

-Greg

On Tue, Feb 24, 2015 at 7:43 AM, Alec <[hidden email]> wrote:

> +1 on both
>
> On Tue Feb 24 2015 at 10:42:41 AM Michael Snoyman <[hidden email]>
> wrote:
>>
>> +1 on <$>
>> +1 on <$
>>
>> On Tue Feb 24 2015 at 5:39:56 PM Edward Kmett <[hidden email]> wrote:
>>>
>>> We have a couple of weeks until the third release candidate for GHC 7.10
>>> goes out the door.
>>>
>>> Along the way with the last couple of release candidates folks have found
>>> some problems with the way we implemented the AMP. [1][2]
>>>
>>> Most notably, we failed to include (<$>) in the Prelude, so the standard
>>> idiom of
>>>
>>> foo <$> bar <*> baz <*> quux
>>>
>>> doesn't work out of the box!
>>>
>>> I'd like to include (<$>) in the Prelude in RC3.
>>>
>>> I'd also like to invite discussion about whether folks believe we should
>>> include (<$) out of the box.
>>>
>>> (<$) has been a member of Functor for a long time, which is only visible
>>> if you import it from Data.Functor or bring in Control.Applicative. There is
>>> an idiom that you use (<*) and (<$) to point to the parts of the structure
>>> that you want to keep the answers from when building longer such Applicative
>>> chains.
>>>
>>> Discussion Period: 2 weeks
>>>
>>> Thank you,
>>> -Edward Kmett
>>>
>>> [1]
>>> http://www.reddit.com/r/haskell/comments/2wzixa/shouldnt_be_in_prelude/
>>> [2] https://plus.google.com/115504368969270249241/posts/URzeDWd7qMp
>>> _______________________________________________
>>> Libraries mailing list
>>> [hidden email]
>>> http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries
>>
>> _______________________________________________
>> Libraries mailing list
>> [hidden email]
>> http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries
>
>
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Re: Proposal: Add (<$>) to Prelude as part of the AMP in GHC 7.10-RC3

Richard Eisenberg-2
In reply to this post by Christopher Reichert
This is a tough call for me.

This change will be very annoying, I think. When updating for 7.10, I was quite surprised that I still needed to import Control.Applicative for <$>, and put in the CPP to do so. Now I'll have to remove that from quite a few modules. Given that we plan only a week for RC3, there are a lot of modules in the ecosystem that will have to be updated within that week!

Of course, an author who doesn't update (by removing the now-redundant import of <$>) just gets a warning, but it's still annoying.

In my opinion, little changes like this, made right before the deadline, make Haskell feel more like a little research language than something meant to support industrial work.

All that said, I desperately miss having <$> in the Prelude in 7.10. Hence the tough call.

0 from me, then.

Richard

On Feb 24, 2015, at 10:47 AM, Christopher Reichert <[hidden email]> wrote:

>
> +1 on <$>. Indifferent on <$.
>
> -Christopher
>
> On Tue, Feb 24 2015, Edward Kmett <[hidden email]> wrote:
>> We have a couple of weeks until the third release candidate for GHC 7.10
>> goes out the door.
>>
>> Along the way with the last couple of release candidates folks have found
>> some problems with the way we implemented the AMP. [1][2]
>>
>> Most notably, we failed to include (<$>) in the Prelude, so the standard
>> idiom of
>>
>> foo <$> bar <*> baz <*> quux
>>
>> doesn't work out of the box!
>>
>> I'd like to include (<$>) in the Prelude in RC3.
>>
>> I'd also like to invite discussion about whether folks believe we should
>> include (<$) out of the box.
>>
>> (<$) has been a member of Functor for a long time, which is only visible if
>> you import it from Data.Functor or bring in Control.Applicative. There is
>> an idiom that you use (<*) and (<$) to point to the parts of the structure
>> that you want to keep the answers from when building longer such
>> Applicative chains.
>>
>> Discussion Period: 2 weeks
>>
>> Thank you,
>> -Edward Kmett
>>
>> [1] http://www.reddit.com/r/haskell/comments/2wzixa/shouldnt_be_in_prelude/
>> [2] https://plus.google.com/115504368969270249241/posts/URzeDWd7qMp
>> _______________________________________________
>> Libraries mailing list
>> [hidden email]
>> http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries
>
> --
> Christopher Reichert
> irc: creichert
> gpg: C81D 18C8 862A 3618 1376  FFA5 6BFC A992 9955 929B
> _______________________________________________
> Libraries mailing list
> [hidden email]
> http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

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Re: Proposal: Add (<$>) to Prelude as part of the AMP in GHC 7.10-RC3

Aloïs Cochard
It is clearly sad that we reached that stage before realizing the problem, but OTOH it would be worst to not fix it now that we still have a (very) last chance.

+1 on both from me.

Unlike Greg I don't think encouraging people to use the QuasiQuoter is a good idea, it's for me obvious that the <$> syntax is widely used, I see it in mostly every open source code I read.

On 24 February 2015 at 17:03, Richard Eisenberg <[hidden email]> wrote:
This is a tough call for me.

This change will be very annoying, I think. When updating for 7.10, I was quite surprised that I still needed to import Control.Applicative for <$>, and put in the CPP to do so. Now I'll have to remove that from quite a few modules. Given that we plan only a week for RC3, there are a lot of modules in the ecosystem that will have to be updated within that week!

Of course, an author who doesn't update (by removing the now-redundant import of <$>) just gets a warning, but it's still annoying.

In my opinion, little changes like this, made right before the deadline, make Haskell feel more like a little research language than something meant to support industrial work.

All that said, I desperately miss having <$> in the Prelude in 7.10. Hence the tough call.

0 from me, then.

Richard

On Feb 24, 2015, at 10:47 AM, Christopher Reichert <[hidden email]> wrote:

>
> +1 on <$>. Indifferent on <$.
>
> -Christopher
>
> On Tue, Feb 24 2015, Edward Kmett <[hidden email]> wrote:
>> We have a couple of weeks until the third release candidate for GHC 7.10
>> goes out the door.
>>
>> Along the way with the last couple of release candidates folks have found
>> some problems with the way we implemented the AMP. [1][2]
>>
>> Most notably, we failed to include (<$>) in the Prelude, so the standard
>> idiom of
>>
>> foo <$> bar <*> baz <*> quux
>>
>> doesn't work out of the box!
>>
>> I'd like to include (<$>) in the Prelude in RC3.
>>
>> I'd also like to invite discussion about whether folks believe we should
>> include (<$) out of the box.
>>
>> (<$) has been a member of Functor for a long time, which is only visible if
>> you import it from Data.Functor or bring in Control.Applicative. There is
>> an idiom that you use (<*) and (<$) to point to the parts of the structure
>> that you want to keep the answers from when building longer such
>> Applicative chains.
>>
>> Discussion Period: 2 weeks
>>
>> Thank you,
>> -Edward Kmett
>>
>> [1] http://www.reddit.com/r/haskell/comments/2wzixa/shouldnt_be_in_prelude/
>> [2] https://plus.google.com/115504368969270249241/posts/URzeDWd7qMp
>> _______________________________________________
>> Libraries mailing list
>> [hidden email]
>> http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries
>
> --
> Christopher Reichert
> irc: creichert
> gpg: C81D 18C8 862A 3618 1376  FFA5 6BFC A992 9955 929B
> _______________________________________________
> Libraries mailing list
> [hidden email]
> http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

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Re: Proposal: Add (<$>) to Prelude as part of the AMP in GHC 7.10-RC3

Nathan van Doorn

Very +1 from me.

On 24 Feb 2015 16:08, "Alois Cochard" <[hidden email]> wrote:
It is clearly sad that we reached that stage before realizing the problem, but OTOH it would be worst to not fix it now that we still have a (very) last chance.

+1 on both from me.

Unlike Greg I don't think encouraging people to use the QuasiQuoter is a good idea, it's for me obvious that the <$> syntax is widely used, I see it in mostly every open source code I read.

On 24 February 2015 at 17:03, Richard Eisenberg <[hidden email]> wrote:
This is a tough call for me.

This change will be very annoying, I think. When updating for 7.10, I was quite surprised that I still needed to import Control.Applicative for <$>, and put in the CPP to do so. Now I'll have to remove that from quite a few modules. Given that we plan only a week for RC3, there are a lot of modules in the ecosystem that will have to be updated within that week!

Of course, an author who doesn't update (by removing the now-redundant import of <$>) just gets a warning, but it's still annoying.

In my opinion, little changes like this, made right before the deadline, make Haskell feel more like a little research language than something meant to support industrial work.

All that said, I desperately miss having <$> in the Prelude in 7.10. Hence the tough call.

0 from me, then.

Richard

On Feb 24, 2015, at 10:47 AM, Christopher Reichert <[hidden email]> wrote:

>
> +1 on <$>. Indifferent on <$.
>
> -Christopher
>
> On Tue, Feb 24 2015, Edward Kmett <[hidden email]> wrote:
>> We have a couple of weeks until the third release candidate for GHC 7.10
>> goes out the door.
>>
>> Along the way with the last couple of release candidates folks have found
>> some problems with the way we implemented the AMP. [1][2]
>>
>> Most notably, we failed to include (<$>) in the Prelude, so the standard
>> idiom of
>>
>> foo <$> bar <*> baz <*> quux
>>
>> doesn't work out of the box!
>>
>> I'd like to include (<$>) in the Prelude in RC3.
>>
>> I'd also like to invite discussion about whether folks believe we should
>> include (<$) out of the box.
>>
>> (<$) has been a member of Functor for a long time, which is only visible if
>> you import it from Data.Functor or bring in Control.Applicative. There is
>> an idiom that you use (<*) and (<$) to point to the parts of the structure
>> that you want to keep the answers from when building longer such
>> Applicative chains.
>>
>> Discussion Period: 2 weeks
>>
>> Thank you,
>> -Edward Kmett
>>
>> [1] http://www.reddit.com/r/haskell/comments/2wzixa/shouldnt_be_in_prelude/
>> [2] https://plus.google.com/115504368969270249241/posts/URzeDWd7qMp
>> _______________________________________________
>> Libraries mailing list
>> [hidden email]
>> http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries
>
> --
> Christopher Reichert
> irc: creichert
> gpg: C81D 18C8 862A 3618 1376  FFA5 6BFC A992 9955 929B
> _______________________________________________
> Libraries mailing list
> [hidden email]
> http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

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Re: Proposal: Add (<$>) to Prelude as part of the AMP in GHC 7.10-RC3

Joseph Abrahamson
In reply to this post by Aloïs Cochard
This one draws me out of silence. Strong +1 on (<$>). 0 on (<$).


Sent from Mailbox


On Tue, Feb 24, 2015 at 11:08 AM, Alois Cochard <[hidden email]> wrote:

It is clearly sad that we reached that stage before realizing the problem, but OTOH it would be worst to not fix it now that we still have a (very) last chance.

+1 on both from me.

Unlike Greg I don't think encouraging people to use the QuasiQuoter is a good idea, it's for me obvious that the <$> syntax is widely used, I see it in mostly every open source code I read.

On 24 February 2015 at 17:03, Richard Eisenberg <[hidden email]> wrote:
This is a tough call for me.

This change will be very annoying, I think. When updating for 7.10, I was quite surprised that I still needed to import Control.Applicative for <$>, and put in the CPP to do so. Now I'll have to remove that from quite a few modules. Given that we plan only a week for RC3, there are a lot of modules in the ecosystem that will have to be updated within that week!

Of course, an author who doesn't update (by removing the now-redundant import of <$>) just gets a warning, but it's still annoying.

In my opinion, little changes like this, made right before the deadline, make Haskell feel more like a little research language than something meant to support industrial work.

All that said, I desperately miss having <$> in the Prelude in 7.10. Hence the tough call.

0 from me, then.

Richard

On Feb 24, 2015, at 10:47 AM, Christopher Reichert <[hidden email]> wrote:

>
> +1 on <$>. Indifferent on <$.
>
> -Christopher
>
> On Tue, Feb 24 2015, Edward Kmett <[hidden email]> wrote:
>> We have a couple of weeks until the third release candidate for GHC 7.10
>> goes out the door.
>>
>> Along the way with the last couple of release candidates folks have found
>> some problems with the way we implemented the AMP. [1][2]
>>
>> Most notably, we failed to include (<$>) in the Prelude, so the standard
>> idiom of
>>
>> foo <$> bar <*> baz <*> quux
>>
>> doesn't work out of the box!
>>
>> I'd like to include (<$>) in the Prelude in RC3.
>>
>> I'd also like to invite discussion about whether folks believe we should
>> include (<$) out of the box.
>>
>> (<$) has been a member of Functor for a long time, which is only visible if
>> you import it from Data.Functor or bring in Control.Applicative. There is
>> an idiom that you use (<*) and (<$) to point to the parts of the structure
>> that you want to keep the answers from when building longer such
>> Applicative chains.
>>
>> Discussion Period: 2 weeks
>>
>> Thank you,
>> -Edward Kmett
>>
>> [1] http://www.reddit.com/r/haskell/comments/2wzixa/shouldnt_be_in_prelude/
>> [2] https://plus.google.com/115504368969270249241/posts/URzeDWd7qMp
>> _______________________________________________
>> Libraries mailing list
>> [hidden email]
>> http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries
>
> --
> Christopher Reichert
> irc: creichert
> gpg: C81D 18C8 862A 3618 1376  FFA5 6BFC A992 9955 929B
> _______________________________________________
> Libraries mailing list
> [hidden email]
> http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

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Re: Proposal: Add (<$>) to Prelude as part of the AMP in GHC 7.10-RC3

Twan van Laarhoven
In reply to this post by Edward Kmett-2
(+1) to both.

On 2015-02-24 16:39, Edward Kmett wrote:

> We have a couple of weeks until the third release candidate for GHC 7.10 goes
> out the door.
>
> Along the way with the last couple of release candidates folks have found some
> problems with the way we implemented the AMP. [1][2]
>
> Most notably, we failed to include (<$>) in the Prelude, so the standard idiom of
>
> foo <$> bar <*> baz <*> quux
>
> doesn't work out of the box!
>
> I'd like to include (<$>) in the Prelude in RC3.
>
> I'd also like to invite discussion about whether folks believe we should include
> (<$) out of the box.
>
> (<$) has been a member of Functor for a long time, which is only visible if you
> import it from Data.Functor or bring in Control.Applicative. There is an idiom
> that you use (<*) and (<$) to point to the parts of the structure that you want
> to keep the answers from when building longer such Applicative chains.
>
> Discussion Period: 2 weeks
>
> Thank you,
> -Edward Kmett
>
> [1] http://www.reddit.com/r/haskell/comments/2wzixa/shouldnt_be_in_prelude/
> [2] https://plus.google.com/115504368969270249241/posts/URzeDWd7qMp
>
>
> _______________________________________________
> Libraries mailing list
> [hidden email]
> http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries
>
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Re: Proposal: Add (<$>) to Prelude as part of the AMP in GHC 7.10-RC3

Roman Cheplyaka-2
In reply to this post by Edward Kmett-2
+1 to both. It would be very sad to go through all these hurdles and not
to have a consistent story in the end.

On 24/02/15 17:39, Edward Kmett wrote:

> We have a couple of weeks until the third release candidate for GHC 7.10
> goes out the door.
>
> Along the way with the last couple of release candidates folks have
> found some problems with the way we implemented the AMP. [1][2]
>
> Most notably, we failed to include (<$>) in the Prelude, so the standard
> idiom of
>
> foo <$> bar <*> baz <*> quux
>
> doesn't work out of the box!
>
> I'd like to include (<$>) in the Prelude in RC3.
>
> I'd also like to invite discussion about whether folks believe we should
> include (<$) out of the box.
>
> (<$) has been a member of Functor for a long time, which is only visible
> if you import it from Data.Functor or bring in Control.Applicative.
> There is an idiom that you use (<*) and (<$) to point to the parts of
> the structure that you want to keep the answers from when building
> longer such Applicative chains.
>
> Discussion Period: 2 weeks
>
> Thank you,
> -Edward Kmett
>
> [1] http://www.reddit.com/r/haskell/comments/2wzixa/shouldnt_be_in_prelude/
> [2] https://plus.google.com/115504368969270249241/posts/URzeDWd7qMp
>
>
> _______________________________________________
> Libraries mailing list
> [hidden email]
> http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries
>

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Re: Proposal: Add (<$>) to Prelude as part of the AMP in GHC 7.10-RC3

Bardur Arantsson-2
In reply to this post by Edward Kmett-2
On 24-02-2015 16:39, Edward Kmett wrote:

> We have a couple of weeks until the third release candidate for GHC 7.10
> goes out the door.
>
> Along the way with the last couple of release candidates folks have found
> some problems with the way we implemented the AMP. [1][2]
>
> Most notably, we failed to include (<$>) in the Prelude, so the standard
> idiom of
>
> foo <$> bar <*> baz <*> quux
>
> doesn't work out of the box!
>
> I'd like to include (<$>) in the Prelude in RC3.
>

+1 on (<$>)
0 on (<$)

... but I must say that I've never actually seen the later in any code
I've inspected. (But then I'm usually not looking at that much
high-level applicative code, code, so...)

> [hidden email]
> http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries
>


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Re: Proposal: Add (<$>) to Prelude as part of the AMP in GHC 7.10-RC3

Gregory Collins-3
In reply to this post by Edward Kmett-2
On Tue, Feb 24, 2015 at 7:39 AM, Edward Kmett <[hidden email]> wrote:
I'd like to include (<$>) in the Prelude in RC3.

I'd also like to invite discussion about whether folks believe we should include (<$) out of the box. 

+2

--
Gregory Collins <[hidden email]>

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Re: Proposal: Add (<$>) to Prelude as part of the AMP in GHC 7.10-RC3

Oliver Charles-3
If <*> is in Prelude (I'm unclear) then I'm +1 on getting <$> there too - <*> is practically useless without <$>!

<$ is handy and I do tend to use it, but I don't feel so strongly about having that in the Prelude (so I'm not going to vote for or against that).

- Ollie

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Re: Proposal: Add (<$>) to Prelude as part of the AMP in GHC 7.10-RC3

Tikhon Jelvis

+1 for me on both.

Besides convenience, symmetry is important so we should export <$> if we export <*> and <$ if <*.

On Feb 24, 2015 9:33 AM, "Oliver Charles" <[hidden email]> wrote:
If <*> is in Prelude (I'm unclear) then I'm +1 on getting <$> there too - <*> is practically useless without <$>!

<$ is handy and I do tend to use it, but I don't feel so strongly about having that in the Prelude (so I'm not going to vote for or against that).

- Ollie

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Re: Proposal: Add (<$>) to Prelude as part of the AMP in GHC 7.10-RC3

Conor McBride-2
In reply to this post by Edward Kmett-2

On 24 Feb 2015, at 15:39, Edward Kmett <[hidden email]> wrote:

> We have a couple of weeks until the third release candidate for GHC 7.10 goes out the door.
>
> Along the way with the last couple of release candidates folks have found some problems with the way we implemented the AMP. [1][2]
>
> Most notably, we failed to include (<$>) in the Prelude, so the standard idiom of
>
> foo <$> bar <*> baz <*> quux
>
> doesn't work out of the box!
>
> I'd like to include (<$>) in the Prelude in RC3.
>
> I'd also like to invite discussion about whether folks believe we should include (<$) out of the box.
>
> (<$) has been a member of Functor for a long time, which is only visible if you import it from Data.Functor or bring in Control.Applicative. There is an idiom that you use (<*) and (<$) to point to the parts of the structure that you want to keep the answers from when building longer such Applicative chains.

For more on this idiom (indeed), let me shamelessly plug

  http://stackoverflow.com/a/15124278/828361

and advise that the two travel together.

I won’t vote. While we are still in the situation that progress breaks code which has been
engineered to work around the prior lack of progress, making progress is simultaneously
a good and bad idea. We should think about how to adapt our language of imports to
accept the only too obvious reality that libraries change over time, so that we might be
allowed to program defensively against sudden outbreaks of common sense.

Apologetically

Conor

>
> Discussion Period: 2 weeks
>
> Thank you,
> -Edward Kmett
>
> [1] http://www.reddit.com/r/haskell/comments/2wzixa/shouldnt_be_in_prelude/
> [2] https://plus.google.com/115504368969270249241/posts/URzeDWd7qMp
> _______________________________________________
> Libraries mailing list
> [hidden email]
> http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

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Re: Proposal: Add (<$>) to Prelude as part of the AMP in GHC 7.10-RC3

Adam Bergmark-2
+1 for <$>, 0 on <$, I rarely use it.



On Tue, Feb 24, 2015 at 7:25 PM, Conor McBride <[hidden email]> wrote:

On 24 Feb 2015, at 15:39, Edward Kmett <[hidden email]> wrote:

> We have a couple of weeks until the third release candidate for GHC 7.10 goes out the door.
>
> Along the way with the last couple of release candidates folks have found some problems with the way we implemented the AMP. [1][2]
>
> Most notably, we failed to include (<$>) in the Prelude, so the standard idiom of
>
> foo <$> bar <*> baz <*> quux
>
> doesn't work out of the box!
>
> I'd like to include (<$>) in the Prelude in RC3.
>
> I'd also like to invite discussion about whether folks believe we should include (<$) out of the box.
>
> (<$) has been a member of Functor for a long time, which is only visible if you import it from Data.Functor or bring in Control.Applicative. There is an idiom that you use (<*) and (<$) to point to the parts of the structure that you want to keep the answers from when building longer such Applicative chains.

For more on this idiom (indeed), let me shamelessly plug

  http://stackoverflow.com/a/15124278/828361

and advise that the two travel together.

I won’t vote. While we are still in the situation that progress breaks code which has been
engineered to work around the prior lack of progress, making progress is simultaneously
a good and bad idea. We should think about how to adapt our language of imports to
accept the only too obvious reality that libraries change over time, so that we might be
allowed to program defensively against sudden outbreaks of common sense.

Apologetically

Conor

>
> Discussion Period: 2 weeks
>
> Thank you,
> -Edward Kmett
>
> [1] http://www.reddit.com/r/haskell/comments/2wzixa/shouldnt_be_in_prelude/
> [2] https://plus.google.com/115504368969270249241/posts/URzeDWd7qMp
> _______________________________________________
> Libraries mailing list
> [hidden email]
> http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

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123