Re: Humble message of support and concern from an interested newbie

[Haowen Liu via Haskell-prime]

That's great! Thank you so much!

Haowen

On 11/11/2021 11:36 AM, Richard Eisenberg wrote:

Great idea to link from the README: 
https://gitlab.haskell.org/ghc/ghc/-/merge_requests/6974

Thanks!
Richard


On Nov 10, 2021, at 2:59 PM, Haowen Liu via Haskell-prime 
 wrote:

On 11/10/2021 11:21 AM, Richard Eisenberg wrote:

On Nov 9, 2021, at 11:26 PM, Haowen Liu  wrote:

And thank you for that link!! I did not know it existed! (Why would they put it 
under a separate GitHub organization? That's why I didn't find it LOL)



That's a good question. I think we did it because it's a GHC-specific process, 
not really about Haskell, per se. But it's also not in the GHC org... which 
maybe it should have been. Where do you think would be a good place to list 
this repo for other people like you to find it in the future?

I'm not sure honestly, but during my search I looked at README in the ghc repo 
and skimmed through the ghc GitHub org: https://github.com/ghc. I feel like 
either would be a great place for people to discover.

(Sorry for the duplicate, but the last one was rejected by the mailing list 
because it was too long.)

Haowen


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Re: Humble message of support and concern from an interested newbie

[Richard Eisenberg]

Great idea to link from the README: 
https://gitlab.haskell.org/ghc/ghc/-/merge_requests/6974

Thanks!
Richard

> On Nov 10, 2021, at 2:59 PM, Haowen Liu via Haskell-prime 
>  wrote:
> 
> On 11/10/2021 11:21 AM, Richard Eisenberg wrote:
>> 
>>> On Nov 9, 2021, at 11:26 PM, Haowen Liu  wrote:
>>> 
>>> And thank you for that link!! I did not know it existed! (Why would they 
>>> put it under a separate GitHub organization? That's why I didn't find it 
>>> LOL)
>>> 
>>> 
>> 
>> That's a good question. I think we did it because it's a GHC-specific 
>> process, not really about Haskell, per se. But it's also not in the GHC 
>> org... which maybe it should have been. Where do you think would be a good 
>> place to list this repo for other people like you to find it in the future?
> 
> I'm not sure honestly, but during my search I looked at README in the ghc 
> repo and skimmed through the ghc GitHub org: https://github.com/ghc. I feel 
> like either would be a great place for people to discover.
> 
> (Sorry for the duplicate, but the last one was rejected by the mailing list 
> because it was too long.)
> 
> Haowen
> 
> 
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Re: Humble message of support and concern from an interested newbie

[Haowen Liu via Haskell-prime]

On 11/10/2021 11:21 AM, Richard Eisenberg wrote:



On Nov 9, 2021, at 11:26 PM, Haowen Liu  wrote:

And thank you for that link!! I did not know it existed! (Why would 
they put it under a separate GitHub organization? That's why I didn't 
find it LOL)





That's a good question. I think we did it because it's a GHC-specific 
process, not really about Haskell, per se. But it's also not in the 
GHC org... which maybe it should have been. Where do you think would 
be a good place to list this repo for other people like you to find it 
in the future?


I'm not sure honestly, but during my search I looked at README in the 
ghc repo and skimmed through the ghc GitHub org: https://github.com/ghc. 
I feel like either would be a great place for people to discover.


(Sorry for the duplicate, but the last one was rejected by the mailing 
list because it was too long.)


Haowen


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Re: Humble message of support and concern from an interested newbie

[Richard Eisenberg]

> On Nov 9, 2021, at 11:26 PM, Haowen Liu  wrote:
> And thank you for that link!! I did not know it existed! (Why would they put 
> it under a separate GitHub organization? That's why I didn't find it LOL)
> 
> 

That's a good question. I think we did it because it's a GHC-specific process, 
not really about Haskell, per se. But it's also not in the GHC org... which 
maybe it should have been. Where do you think would be a good place to list 
this repo for other people like you to find it in the future?

Thanks!
Richard
> BTW I just realized that my previous responses to Cale is sent privately 
> because I forgot to reply all... Sad...
> 
> Best,
> Haowen
> 
> On 11/9/2021 7:57 PM, Richard Eisenberg wrote:
>> I want to chime in with agreement that the GHC2021 push may meet many of the 
>> goals you may be after. I also want to bring in a further aspect of 
>> challenge in producing a new Report: we don't really understand Haskell well 
>> enough to do so.
>> 
>> The two Reports do a very fine job of specifying the behavior of the 
>> language. However, for almost any extension that isn't in the Report, there 
>> are corner cases that are hard to describe and nail down. We could, of 
>> course, just write down GHC's algorithm and try to standardize it... but 
>> that feels like cheating. Instead, we would like to be able to describe 
>> Haskell's behavior declaratively. Yet, when the Haskell2020 team tried to 
>> identify an extension that was both stable enough to considered ready for 
>> inclusion in the Report and could be described declaratively, we failed. 
>> (Yes, even FlexibleContexts has dark corners.) The lesson learned here is 
>> not that writing a new Report would be impossible -- just that it would be 
>> very difficult: we would likely have to do fresh programming-language 
>> research just to be able to write down GHC's behavior accurately and 
>> declaratively. As much as I would love to receive a Haskell2020 Report as a 
>> birthday present, I personally do not think having it is worth the 
>> considerable expense.
>> 
>> Thanks for your Haskell enthusiasm! If you do want to see evidence of 
>> continued growth of the language's main implementation, check out 
>> https://github.com/ghc-proposals/ghc-proposals/ 
>> , quite an active space of 
>> language design.
>> 
>> Richard
>> 
>>> On Nov 8, 2021, at 10:45 PM, Cale Gibbard >> > wrote:
>>> 
>>> To some extent I can agree with the view that certain small things should 
>>> possibly be folded in, but from another perspective, I actually like the 
>>> way that major language features are modular, and I can tell a lot about 
>>> what to expect by looking at the top of a file. There are also things that 
>>> most people agree are a decent part of the language, but should also 
>>> probably never stop being extensions, like FFI and Template Haskell.
>>> 
>>> But while warning users about certain things being controversial or 
>>> unstable and certain things being less so could be something that one could 
>>> put in the Report, I wouldn't want any change to the language to start 
>>> there. If you try to make changes to the language as it exists while also 
>>> documenting it, you'll end up in a season of bikeshedding that will never 
>>> end, and at the same time end up describing a creature that doesn't exist. 
>>> See the ghc-proposals mailing list for a more appropriate place to begin 
>>> with changes to the language at present. See also this proposal: 
>>> https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0380-ghc2021.rst
>>>  
>>> 
>>>  which has been implemented in the latest GHC 9.2 for defining a particular 
>>> "GHC2021" agglomeration of some of the most commonly used extensions. 
>>> There's also a table there containing some nice usage statistics that were 
>>> collected from Hackage.
>>> 
>>> From the other side of things, I think the Report, if revived, should not 
>>> shy away from trying to describe as many of the extensions as people have 
>>> the energy to describe, controversial/unstable or not. The most important 
>>> purpose for which I'd really like to have a Report at present would be to 
>>> properly clarify the interactions between extensions. For example, how do 
>>> you figure out what happens when you use functional dependencies and type 
>>> equality constraints together? Exactly how does GHC know when to 
>>> instantiate a quantified constraint, and how does that interact with type 
>>> family expansion? Even the technical papers written about these features 
>>> don't necessarily answer questions about these interactions, so if you 
>>> start using them together, cases can arise where it can be difficult to 
>>> determine what's going to happen. Often things will just work as you might 
>>> hope, even if you're not entirely certain 

Re: Humble message of support and concern from an interested newbie

[Haowen Liu via Haskell-prime]

Hi Richard,

Thank you for chiming in! I think I now have a better idea what happened 
several years ago when the Haskell2020 effort died down...


And thank you for that link!! I did not know it existed! (Why would they 
put it under a separate GitHub organization? That's why I didn't find it 
LOL)


BTW I just realized that my previous responses to Cale is sent privately 
because I forgot to reply all... Sad...


Best,
Haowen

On 11/9/2021 7:57 PM, Richard Eisenberg wrote:
I want to chime in with agreement that the GHC2021 push may meet many 
of the goals you may be after. I also want to bring in a further 
aspect of challenge in producing a new Report: we don't really 
understand Haskell well enough to do so.


The two Reports do a very fine job of specifying the behavior of the 
language. However, for almost any extension that isn't in the Report, 
there are corner cases that are hard to describe and nail down. We 
could, of course, just write down GHC's algorithm and try to 
standardize it... but that feels like cheating. Instead, we would like 
to be able to describe Haskell's behavior declaratively. Yet, when the 
Haskell2020 team tried to identify an extension that was both stable 
enough to considered ready for inclusion in the Report and could be 
described declaratively, we failed. (Yes, even FlexibleContexts has 
dark corners.) The lesson learned here is not that writing a new 
Report would be impossible -- just that it would be very difficult: we 
would likely have to do fresh programming-language research just to be 
able to write down GHC's behavior accurately and declaratively. As 
much as I would love to receive a Haskell2020 Report as a birthday 
present, I personally do not think having it is worth the considerable 
expense.


Thanks for your Haskell enthusiasm! If you do want to see evidence of 
continued growth of the language's main implementation, check out 
https://github.com/ghc-proposals/ghc-proposals/, quite an active space 
of language design.


Richard


On Nov 8, 2021, at 10:45 PM, Cale Gibbard  wrote:

To some extent I can agree with the view that certain small things 
should possibly be folded in, but from another perspective, I 
actually like the way that major language features are modular, and I 
can tell a lot about what to expect by looking at the top of a file. 
There are also things that most people agree are a decent part of the 
language, but should also probably never stop being extensions, like 
FFI and Template Haskell.


But while warning users about certain things being controversial or 
unstable and certain things being less so could be something that one 
could put in the Report, I wouldn't want any change to the language 
to start there. If you try to make changes to the language as it 
exists while also documenting it, you'll end up in a season of 
bikeshedding that will never end, and at the same time end up 
describing a creature that doesn't exist. See the ghc-proposals 
mailing list for a more appropriate place to begin with changes to 
the language at present. See also this proposal: 
https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0380-ghc2021.rst 
which has been implemented in the latest GHC 9.2 for defining a 
particular "GHC2021" agglomeration of some of the most commonly used 
extensions. There's also a table there containing some nice usage 
statistics that were collected from Hackage.


From the other side of things, I think the Report, if revived, should 
not shy away from trying to describe as many of the extensions as 
people have the energy to describe, controversial/unstable or not. 
The most important purpose for which I'd really like to have a Report 
at present would be to properly clarify the interactions between 
extensions. For example, how do you figure out what happens when you 
use functional dependencies and type equality constraints together? 
Exactly how does GHC know when to instantiate a quantified 
constraint, and how does that interact with type family expansion? 
Even the technical papers written about these features don't 
necessarily answer questions about these interactions, so if you 
start using them together, cases can arise where it can be difficult 
to determine what's going to happen. Often things will just work as 
you might hope, even if you're not entirely certain why. Once in a 
blue moon though, you might just get weird error messages that don't 
quite make sense, but seem to indicate that the compiler is very 
confused. Then perhaps you try a newer GHC, and find out that 
particular combination of things is now simply forbidden outright. So 
it would be nice to really get everything into a single framework of 
description, and there have been some rather large efforts in the 
direction of unifying large chunks of it, like the OutsideIn(X) paper 
(which is already perhaps too technical compared with the Report), 
but it's by no means easy.


Also, typical users of the language eventually 

Re: Humble message of support and concern from an interested newbie

[Richard Eisenberg]

I want to chime in with agreement that the GHC2021 push may meet many of the 
goals you may be after. I also want to bring in a further aspect of challenge 
in producing a new Report: we don't really understand Haskell well enough to do 
so.

The two Reports do a very fine job of specifying the behavior of the language. 
However, for almost any extension that isn't in the Report, there are corner 
cases that are hard to describe and nail down. We could, of course, just write 
down GHC's algorithm and try to standardize it... but that feels like cheating. 
Instead, we would like to be able to describe Haskell's behavior declaratively. 
Yet, when the Haskell2020 team tried to identify an extension that was both 
stable enough to considered ready for inclusion in the Report and could be 
described declaratively, we failed. (Yes, even FlexibleContexts has dark 
corners.) The lesson learned here is not that writing a new Report would be 
impossible -- just that it would be very difficult: we would likely have to do 
fresh programming-language research just to be able to write down GHC's 
behavior accurately and declaratively. As much as I would love to receive a 
Haskell2020 Report as a birthday present, I personally do not think having it 
is worth the considerable expense.

Thanks for your Haskell enthusiasm! If you do want to see evidence of continued 
growth of the language's main implementation, check out 
https://github.com/ghc-proposals/ghc-proposals/, quite an active space of 
language design.

Richard

> On Nov 8, 2021, at 10:45 PM, Cale Gibbard  wrote:
> 
> To some extent I can agree with the view that certain small things should 
> possibly be folded in, but from another perspective, I actually like the way 
> that major language features are modular, and I can tell a lot about what to 
> expect by looking at the top of a file. There are also things that most 
> people agree are a decent part of the language, but should also probably 
> never stop being extensions, like FFI and Template Haskell.
> 
> But while warning users about certain things being controversial or unstable 
> and certain things being less so could be something that one could put in the 
> Report, I wouldn't want any change to the language to start there. If you try 
> to make changes to the language as it exists while also documenting it, 
> you'll end up in a season of bikeshedding that will never end, and at the 
> same time end up describing a creature that doesn't exist. See the 
> ghc-proposals mailing list for a more appropriate place to begin with changes 
> to the language at present. See also this proposal: 
> https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0380-ghc2021.rst
>  
> 
>  which has been implemented in the latest GHC 9.2 for defining a particular 
> "GHC2021" agglomeration of some of the most commonly used extensions. There's 
> also a table there containing some nice usage statistics that were collected 
> from Hackage.
> 
> From the other side of things, I think the Report, if revived, should not shy 
> away from trying to describe as many of the extensions as people have the 
> energy to describe, controversial/unstable or not. The most important purpose 
> for which I'd really like to have a Report at present would be to properly 
> clarify the interactions between extensions. For example, how do you figure 
> out what happens when you use functional dependencies and type equality 
> constraints together? Exactly how does GHC know when to instantiate a 
> quantified constraint, and how does that interact with type family expansion? 
> Even the technical papers written about these features don't necessarily 
> answer questions about these interactions, so if you start using them 
> together, cases can arise where it can be difficult to determine what's going 
> to happen. Often things will just work as you might hope, even if you're not 
> entirely certain why. Once in a blue moon though, you might just get weird 
> error messages that don't quite make sense, but seem to indicate that the 
> compiler is very confused. Then perhaps you try a newer GHC, and find out 
> that particular combination of things is now simply forbidden outright. So it 
> would be nice to really get everything into a single framework of 
> description, and there have been some rather large efforts in the direction 
> of unifying large chunks of it, like the OutsideIn(X) paper (which is already 
> perhaps too technical compared with the Report), but it's by no means easy.
> 
> Also, typical users of the language eventually have to contend with most of 
> the extensions, controversial or not, and it would be very nice to have a 
> reference for what things are supposed to mean regardless of whether we'd 
> rather they not be in the language at all. The Report would also be a great 
> place to have a little bit of guidance and 

Re: Humble message of support and concern from an interested newbie

[Cale Gibbard]

To some extent I can agree with the view that certain small things should
possibly be folded in, but from another perspective, I actually like the
way that major language features are modular, and I can tell a lot about
what to expect by looking at the top of a file. There are also things that
most people agree are a decent part of the language, but should also
probably never stop being extensions, like FFI and Template Haskell.

But while warning users about certain things being controversial or
unstable and certain things being less so could be something that one could
put in the Report, I wouldn't want any change to the language to start
there. If you try to make changes to the language as it exists while also
documenting it, you'll end up in a season of bikeshedding that will never
end, and at the same time end up describing a creature that doesn't exist.
See the ghc-proposals mailing list for a more appropriate place to begin
with changes to the language at present. See also this proposal:
https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0380-ghc2021.rst
which has been implemented in the latest GHC 9.2 for defining a particular
"GHC2021" agglomeration of some of the most commonly used extensions.
There's also a table there containing some nice usage statistics that were
collected from Hackage.

>From the other side of things, I think the Report, if revived, should not
shy away from trying to describe as many of the extensions as people have
the energy to describe, controversial/unstable or not. The most important
purpose for which I'd really like to have a Report at present would be to
properly clarify the interactions between extensions. For example, how do
you figure out what happens when you use functional dependencies and type
equality constraints together? Exactly how does GHC know when to
instantiate a quantified constraint, and how does that interact with type
family expansion? Even the technical papers written about these features
don't necessarily answer questions about these interactions, so if you
start using them together, cases can arise where it can be difficult to
determine what's going to happen. Often things will just work as you might
hope, even if you're not entirely certain why. Once in a blue moon though,
you might just get weird error messages that don't quite make sense, but
seem to indicate that the compiler is very confused. Then perhaps you try a
newer GHC, and find out that particular combination of things is now simply
forbidden outright. So it would be nice to really get everything into a
single framework of description, and there have been some rather large
efforts in the direction of unifying large chunks of it, like the
OutsideIn(X) paper (which is already perhaps too technical compared with
the Report), but it's by no means easy.

Also, typical users of the language eventually have to contend with most of
the extensions, controversial or not, and it would be very nice to have a
reference for what things are supposed to mean regardless of whether we'd
rather they not be in the language at all. The Report would also be a great
place to have a little bit of guidance and statistics on how
stable/well-used these things are.

 - Cale

On Mon, 8 Nov 2021 at 21:41, Haowen Liu  wrote:

> Hi Cale and others,
>
> Thank you Cale so so much for such a detailed explanation!
>
> I agree with you that an evolving standard is only useful as a
> normalizing force if we have multiple compilers, like C/C++. Such is the
> same for the standard as documentation since GHC documentation is really
> what people should refer to.
>
> I realize I'm in no way qualified to make those points but in my meager
> experience with Haskell, an evolving standard could serve as a very
> valuable verdict of the merits of various GHC extensions. AFAIK, some
> GHC extensions are very widely adopted and some are considered
> misfeatures. The Haskell202X could simply incorporate a list of
> agreeable extensions into the core language and those less agreeable
> ones could stay as extensions or whatever the GHC community decides to
> do with them.
>
> I think such kind of Haskell202X is advantageous in the following ways:
>
> 1. It is less time consuming than radical language changes. And the very
> fact that the Haskell202X effort is halted proves that Haskell currently
> demands no radical changes (at least not the ones that can't be
> implemented as a GHC extension).
>
> 2. We no longer to enable a series of widely used plugins. Many of the
> extensions integrate so nicely into the language that I don't think
> programmers should be required to manually enable them to use them.
> According to Sandy Maguire, "In GHC 8.6.5, there are 125 different
> language extensions, and an analysis shows that 10% of Haskell files in
> the wild enable 10 or more extensions." [1]
>
> 3. People are less likely to use those less agreeable extensions because
> at that time enabling extensions would be a rare 

Re: Humble message of support and concern from an interested newbie

[Cale Gibbard]

The tricky thing is that while a new document describing the language in
detail would be welcomed, it's hard for people to justify doing all the
work that's involved in producing a new document that's substantially more
helpful than the Haskell 2010 or '98 Report. Right at the moment, there's
essentially one practically-usable implementation of the language, GHC
(unless maybe you count GHCJS, and that's sharing GHC's frontend
regardless). So the demand for a document that says what needs to be shared
between implementations of the language is low. Personally, I think
producing a description of what GHC is meant to be implementing, with as
complete coverage of all the extensions as can be managed, i.e. a report,
is something that would be quite valuable. However, that's a very large
task, and most of the people who would be well-suited to produce that
document have other constraints on their time. I don't think there's a
pressing need for a normative standards document at the moment though.

Maybe if some Haskell-using company were to get large enough to devote a
team to working on a new general purpose Haskell compiler for some reason,
or there was a big open-source push for a second Haskell compiler, there
would be cause for a normative standard. But for now, everyone's been more
or less content with working together extending GHC rather than building
something entirely new. (I would have a fair amount of sympathy for someone
wanting to start fresh though. I have my own list of reasons for which I
can imagine wanting to take a shot at reimplementing the language, but I
don't really have the time or energy for it myself.)

For the descriptive side of things, most people get by right now with the
GHC User's Guide, and failing that, there are often papers that go into
much greater detail about the individual extensions. If you want to really
understand the finer details of how those extensions all interact with one
another though, there's presently nothing apart from the compiler itself
(and even then, how they *ought* to interact is a different question from
how they *do* interact). Understanding that and describing it all in a
precise way is a big and difficult task, and it's one whose cost sadly
might outweigh its benefits, especially if the progress toward a new
Haskell Report is any indication.

Even more, I think most would be delighted to see a denotational semantics
for all of Haskell again. But it's one of those things which is difficult
to produce in the first place, and then unless a process were in place to
have it track the implementation, it would almost immediately fall out of
date.

That said, I can imagine there will be a point where the process to write a
new Report kicks back off, I just don't think it's been at the forefront of
most people's minds lately.

 - Cale

On Mon, 8 Nov 2021 at 17:55, Haowen Liu via Haskell-prime <
haskell-prime@haskell.org> wrote:

> Hi,
>
> I hope this email finds you all well. I'm a newbie only starting with
> Haskell very recently, but I LOVE what I'm discovering with Haskell and
> its ecosystem. That's why I was shocked to see that the latest Haskell
> standard is still Haskell2010, and activities on this list has halted
> for 3 years.
>
> I skimmed through the Haskell2010 spec and understand deeply that the
> next Haskell standard will be an equally challenging enterprise. I,
> although yet to be sufficiently familiar with Haskell, want to let you
> all know that I'm hugely grateful for all the work you have done, and
> I'm more than willing to extend any kind of help moving forward with the
> next Haskell standard. If people are still interested in developing
> Haskell202X, and if people need some sort of secretary, editor, errand
> runner, or whatever, please let me know and I can help.
>
> Grateful, concerned, and eager to help,
> Haowen Liu
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>
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