Hi. I'm new to this mailing list and have a few questions.

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Hi. I'm new to this mailing list and have a few questions.

Anselm Schüler (conversations subemail)

First of all, in general, I’m new to mailing lists (as used for discussions) in general, so a question about that:

When subscribed to the mailing list, do you get every message, or are some discussions hidden?

 

Second of all, I’d like to know what kinds of messages are appropriate here. I’m not familiar with coding compilers or anything of the like, so I’m somewhat afraid of offering unhelpful comments or being just woefully underqualified to participate here.

For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement (that might be wrong). Is it alright if I submit that here or should I use some other forum?

 

Thank you in advance for the answers.

 

Anselm Schüler

www.anselmschueler.com

[hidden email]


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Re: Hi. I'm new to this mailing list and have a few questions.

Richard Eisenberg-5
Hi Anselm,

Welcome!

A good way of getting used to a list like this one is to wait a little while and observe what kind of messages others send; this will give you a feel for how the list is used. If you're impatient, you can also check out the archives at https://mail.haskell.org/pipermail/ghc-devs/.

As for a feature request: if your feature changes the language GHC accepts (most do), the right place to post is at https://github.com/ghc-proposals/ghc-proposals. There is a description of how to proceed on that page. Proposals submitted there get debated within the community and then eventually sent to a GHC Steering Committee for a vote on acceptance or rejection. Then, we worry about implementing it. If you have a suggestion that does not change the language GHC accepts, you can post an Issue at https://gitlab.haskell.org/ghc/ghc/.

I hope this is helpful!
Richard

On Aug 4, 2020, at 8:59 AM, Anselm Schüler (conversations subemail) <[hidden email]> wrote:

First of all, in general, I’m new to mailing lists (as used for discussions) in general, so a question about that:
When subscribed to the mailing list, do you get every message, or are some discussions hidden?
 
Second of all, I’d like to know what kinds of messages are appropriate here. I’m not familiar with coding compilers or anything of the like, so I’m somewhat afraid of offering unhelpful comments or being just woefully underqualified to participate here.
For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement (that might be wrong). Is it alright if I submit that here or should I use some other forum?
 
Thank you in advance for the answers.
 
Anselm Schüler
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ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs


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RE: Hi. I'm new to this mailing list and have a few questions.

GHC - devs mailing list

Welcome Anselm.  ghc-devs is a very informal mailing list, and we welcome newcomers.

 

For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement

 

What Richard says is right, but you should feel free to fly the kite on this list if you want – or on Haskell Café – to get some idea of whether others seem warm about the idea, before writing a full proposal. 

 

Simon

 

From: ghc-devs <[hidden email]> On Behalf Of Richard Eisenberg
Sent: 04 August 2020 16:05
To: "Anselm Schüler (conversations subemail)" <[hidden email]>
Cc: [hidden email]
Subject: Re: Hi. I'm new to this mailing list and have a few questions.

 

Hi Anselm,

 

Welcome!

 

A good way of getting used to a list like this one is to wait a little while and observe what kind of messages others send; this will give you a feel for how the list is used. If you're impatient, you can also check out the archives at https://mail.haskell.org/pipermail/ghc-devs/.

 

As for a feature request: if your feature changes the language GHC accepts (most do), the right place to post is at https://github.com/ghc-proposals/ghc-proposals. There is a description of how to proceed on that page. Proposals submitted there get debated within the community and then eventually sent to a GHC Steering Committee for a vote on acceptance or rejection. Then, we worry about implementing it. If you have a suggestion that does not change the language GHC accepts, you can post an Issue at https://gitlab.haskell.org/ghc/ghc/.

 

I hope this is helpful!

Richard



On Aug 4, 2020, at 8:59 AM, Anselm Schüler (conversations subemail) <[hidden email]> wrote:

 

First of all, in general, I’m new to mailing lists (as used for discussions) in general, so a question about that:

When subscribed to the mailing list, do you get every message, or are some discussions hidden?

 

Second of all, I’d like to know what kinds of messages are appropriate here. I’m not familiar with coding compilers or anything of the like, so I’m somewhat afraid of offering unhelpful comments or being just woefully underqualified to participate here.

For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement (that might be wrong). Is it alright if I submit that here or should I use some other forum?

 

Thank you in advance for the answers.

 

Anselm Schüler

_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

 


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AW: RE: Hi. I'm new to this mailing list and have a few questions.

Anselm Schüler (conversations subemail)

Thank you for the nice introduction :) !

I will check out the GHC proposals site.

And following Simon’s (I hope addressing with first name is OK) suggestion, I’m going to give an outline of the idea.

 

The idea is to extend type application syntax to enable explicit assignment of types to specific type variables.

For instance, say I have f :: forall a b. (a, b) -> (b, a), and I want to apply the type [String] to it. My only option is to do

f @([String]) :: forall b. ([String], b) -> (b, [String])

—but what if, instead, I want a function of type forall a. (a, [String]) -> ([String], a)?

I propose the following syntax:

f @{b = [String]} :: forall a. ([String], b) -> (b, [String])

This wouldn’t break any existing programs since using record syntax here is already disallowed and met with an error message.

A question is of course the symbol used for assignment (~, =, ::, or ->?).

 

I hope the code shows up as a monospace font on your end. I used the IBM Plex Mono font, which is open-source.

 

Anselm Schüler

www.anselmschueler.com

[hidden email]

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 18:44
To: [hidden email]; [hidden email]
Cc: [hidden email]
Subject: RE: Hi. I'm new to this mailing list and have a few questions.

 

Welcome Anselm.  ghc-devs is a very informal mailing list, and we welcome newcomers.

 

For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement

 

What Richard says is right, but you should feel free to fly the kite on this list if you want – or on Haskell Café – to get some idea of whether others seem warm about the idea, before writing a full proposal. 

 

Simon

 

From: ghc-devs <[hidden email]> On Behalf Of Richard Eisenberg
Sent: 04 August 2020 16:05
To: "Anselm Schüler (conversations subemail)" <[hidden email]>
Cc: [hidden email]
Subject: Re: Hi. I'm new to this mailing list and have a few questions.

 

Hi Anselm,

 

Welcome!

 

A good way of getting used to a list like this one is to wait a little while and observe what kind of messages others send; this will give you a feel for how the list is used. If you're impatient, you can also check out the archives at https://mail.haskell.org/pipermail/ghc-devs/.

 

As for a feature request: if your feature changes the language GHC accepts (most do), the right place to post is at https://github.com/ghc-proposals/ghc-proposals. There is a description of how to proceed on that page. Proposals submitted there get debated within the community and then eventually sent to a GHC Steering Committee for a vote on acceptance or rejection. Then, we worry about implementing it. If you have a suggestion that does not change the language GHC accepts, you can post an Issue at https://gitlab.haskell.org/ghc/ghc/.

 

I hope this is helpful!

Richard

 

On Aug 4, 2020, at 8:59 AM, Anselm Schüler (conversations subemail) <[hidden email]> wrote:

 

First of all, in general, I’m new to mailing lists (as used for discussions) in general, so a question about that:

When subscribed to the mailing list, do you get every message, or are some discussions hidden?

 

Second of all, I’d like to know what kinds of messages are appropriate here. I’m not familiar with coding compilers or anything of the like, so I’m somewhat afraid of offering unhelpful comments or being just woefully underqualified to participate here.

For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement (that might be wrong). Is it alright if I submit that here or should I use some other forum?

 

Thank you in advance for the answers.

 

Anselm Schüler

_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

 

 


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Re: RE: Hi. I'm new to this mailing list and have a few questions.

Iavor Diatchki
I think that's a nice idea.  In Cryptol we have both positional and named applications (as in your outline) and it works very nicely, I think.

-Iavor

On Tue, Aug 4, 2020 at 10:46 AM Anselm Schüler (conversations subemail) <[hidden email]> wrote:

Thank you for the nice introduction :) !

I will check out the GHC proposals site.

And following Simon’s (I hope addressing with first name is OK) suggestion, I’m going to give an outline of the idea.

 

The idea is to extend type application syntax to enable explicit assignment of types to specific type variables.

For instance, say I have f :: forall a b. (a, b) -> (b, a), and I want to apply the type [String] to it. My only option is to do

f @([String]) :: forall b. ([String], b) -> (b, [String])

—but what if, instead, I want a function of type forall a. (a, [String]) -> ([String], a)?

I propose the following syntax:

f @{b = [String]} :: forall a. ([String], b) -> (b, [String])

This wouldn’t break any existing programs since using record syntax here is already disallowed and met with an error message.

A question is of course the symbol used for assignment (~, =, ::, or ->?).

 

I hope the code shows up as a monospace font on your end. I used the IBM Plex Mono font, which is open-source.

 

Anselm Schüler

www.anselmschueler.com

[hidden email]

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 18:44
To: [hidden email]; [hidden email]
Cc: [hidden email]
Subject: RE: Hi. I'm new to this mailing list and have a few questions.

 

Welcome Anselm.  ghc-devs is a very informal mailing list, and we welcome newcomers.

 

For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement

 

What Richard says is right, but you should feel free to fly the kite on this list if you want – or on Haskell Café – to get some idea of whether others seem warm about the idea, before writing a full proposal. 

 

Simon

 

From: ghc-devs <[hidden email]> On Behalf Of Richard Eisenberg
Sent: 04 August 2020 16:05
To: "Anselm Schüler (conversations subemail)" <[hidden email]>
Cc: [hidden email]
Subject: Re: Hi. I'm new to this mailing list and have a few questions.

 

Hi Anselm,

 

Welcome!

 

A good way of getting used to a list like this one is to wait a little while and observe what kind of messages others send; this will give you a feel for how the list is used. If you're impatient, you can also check out the archives at https://mail.haskell.org/pipermail/ghc-devs/.

 

As for a feature request: if your feature changes the language GHC accepts (most do), the right place to post is at https://github.com/ghc-proposals/ghc-proposals. There is a description of how to proceed on that page. Proposals submitted there get debated within the community and then eventually sent to a GHC Steering Committee for a vote on acceptance or rejection. Then, we worry about implementing it. If you have a suggestion that does not change the language GHC accepts, you can post an Issue at https://gitlab.haskell.org/ghc/ghc/.

 

I hope this is helpful!

Richard

 

On Aug 4, 2020, at 8:59 AM, Anselm Schüler (conversations subemail) <[hidden email]> wrote:

 

First of all, in general, I’m new to mailing lists (as used for discussions) in general, so a question about that:

When subscribed to the mailing list, do you get every message, or are some discussions hidden?

 

Second of all, I’d like to know what kinds of messages are appropriate here. I’m not familiar with coding compilers or anything of the like, so I’m somewhat afraid of offering unhelpful comments or being just woefully underqualified to participate here.

For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement (that might be wrong). Is it alright if I submit that here or should I use some other forum?

 

Thank you in advance for the answers.

 

Anselm Schüler

_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

 

 

_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

_______________________________________________
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[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
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Re: AW: RE: Hi. I'm new to this mailing list and have a few questions.

Rowan Goemans
In reply to this post by Anselm Schüler (conversations subemail)

Just as a heads up. You can achieve what you want already by doing:

f @_ @([String]) :: forall a. (a, [String]) -> ([String], a)

Best regards,

Rowan Goemans

On 8/4/20 7:45 PM, Anselm Schüler (conversations subemail) wrote:

Thank you for the nice introduction :) !

I will check out the GHC proposals site.

And following Simon’s (I hope addressing with first name is OK) suggestion, I’m going to give an outline of the idea.

 

The idea is to extend type application syntax to enable explicit assignment of types to specific type variables.

For instance, say I have f :: forall a b. (a, b) -> (b, a), and I want to apply the type [String] to it. My only option is to do

f @([String]) :: forall b. ([String], b) -> (b, [String])

—but what if, instead, I want a function of type forall a. (a, [String]) -> ([String], a)?

I propose the following syntax:

f @{b = [String]} :: forall a. ([String], b) -> (b, [String])

This wouldn’t break any existing programs since using record syntax here is already disallowed and met with an error message.

A question is of course the symbol used for assignment (~, =, ::, or ->?).

 

I hope the code shows up as a monospace font on your end. I used the IBM Plex Mono font, which is open-source.

 

Anselm Schüler

www.anselmschueler.com

[hidden email]

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 18:44
To: [hidden email]; [hidden email]
Cc: [hidden email]
Subject: RE: Hi. I'm new to this mailing list and have a few questions.

 

Welcome Anselm.  ghc-devs is a very informal mailing list, and we welcome newcomers.

 

For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement

 

What Richard says is right, but you should feel free to fly the kite on this list if you want – or on Haskell Café – to get some idea of whether others seem warm about the idea, before writing a full proposal. 

 

Simon

 

From: ghc-devs [hidden email] On Behalf Of Richard Eisenberg
Sent: 04 August 2020 16:05
To: "Anselm Schüler (conversations subemail)" [hidden email]
Cc: [hidden email]
Subject: Re: Hi. I'm new to this mailing list and have a few questions.

 

Hi Anselm,

 

Welcome!

 

A good way of getting used to a list like this one is to wait a little while and observe what kind of messages others send; this will give you a feel for how the list is used. If you're impatient, you can also check out the archives at https://mail.haskell.org/pipermail/ghc-devs/.

 

As for a feature request: if your feature changes the language GHC accepts (most do), the right place to post is at https://github.com/ghc-proposals/ghc-proposals. There is a description of how to proceed on that page. Proposals submitted there get debated within the community and then eventually sent to a GHC Steering Committee for a vote on acceptance or rejection. Then, we worry about implementing it. If you have a suggestion that does not change the language GHC accepts, you can post an Issue at https://gitlab.haskell.org/ghc/ghc/.

 

I hope this is helpful!

Richard

 

On Aug 4, 2020, at 8:59 AM, Anselm Schüler (conversations subemail) <[hidden email]> wrote:

 

First of all, in general, I’m new to mailing lists (as used for discussions) in general, so a question about that:

When subscribed to the mailing list, do you get every message, or are some discussions hidden?

 

Second of all, I’d like to know what kinds of messages are appropriate here. I’m not familiar with coding compilers or anything of the like, so I’m somewhat afraid of offering unhelpful comments or being just woefully underqualified to participate here.

For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement (that might be wrong). Is it alright if I submit that here or should I use some other forum?

 

Thank you in advance for the answers.

 

Anselm Schüler

_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

 

 


_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
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Re: Hi. I'm new to this mailing list and have a few questions.

Ben Gamari-2
In reply to this post by Anselm Schüler (conversations subemail)
"Anselm Schüler (conversations subemail)"
<[hidden email]> writes:

> First of all, in general, I’m new to mailing lists (as used for
> discussions) in general, so a question about that:
>
Hi Anselm,

Welcome to the GHC community. To add to what Richard and Simon have
shared...

> When subscribed to the mailing list, do you get every message, or are
> some discussions hidden?
>
>  
>
> Second of all, I’d like to know what kinds of messages are appropriate
> here. I’m not familiar with coding compilers or anything of the like,
> so I’m somewhat afraid of offering unhelpful comments or being just
> woefully underqualified to participate here.
>
You shouldn't worry. We are all learning.

> For example, I have a feature idea in the back of my mind, which I
> imagine would be easy to implement (that might be wrong). Is it
> alright if I submit that here or should I use some other forum?
>
The answer here depends upon what sort of feature you are thinking of.
As Simon and Richard said, the proposals process [1] exists to hone
proposals to the language and large compiler features.

In the case of a smaller feature of the compiler itself (e.g. a new GHCi
command or GHC API interface), then it can sometimes be useful to either
open an issue or mailing list thread first to help guide your thinking
and help others get a sense for the scale of the change; it's possible
that in this case a proposal isn't necessary.

Don't hesitate to reach out if you would like further guidance.

Cheers,

- Ben

_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

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Re: Hi. I'm new to this mailing list and have a few questions.

Vladislav Zavialov-2
In reply to this post by Anselm Schüler (conversations subemail)
This feature has already been proposed:

  https://github.com/ghc-proposals/ghc-proposals/pull/196

But the discussion there has stalled. You may want to take a look at the existing discussion, and if you see a way forward, comment on the proposal (or open a competing one).

- Vlad

> On 4 Aug 2020, at 20:45, Anselm Schüler (conversations subemail) <[hidden email]> wrote:
>
> Thank you for the nice introduction :) !
> I will check out the GHC proposals site.
> And following Simon’s (I hope addressing with first name is OK) suggestion, I’m going to give an outline of the idea.
>  
> The idea is to extend type application syntax to enable explicit assignment of types to specific type variables.
> For instance, say I have f :: forall a b. (a, b) -> (b, a), and I want to apply the type [String] to it. My only option is to do
> f @([String]) :: forall b. ([String], b) -> (b, [String])
> —but what if, instead, I want a function of type forall a. (a, [String]) -> ([String], a)?
> I propose the following syntax:
> f @{b = [String]} :: forall a. ([String], b) -> (b, [String])
> This wouldn’t break any existing programs since using record syntax here is already disallowed and met with an error message.
> A question is of course the symbol used for assignment (~, =, ::, or ->?).
>  
> I hope the code shows up as a monospace font on your end. I used the IBM Plex Mono font, which is open-source.
>  
> Anselm Schüler
> www.anselmschueler.com
> [hidden email]
>  
> From: Simon Peyton Jones
> Sent: Tuesday, August 4, 2020 18:44
> To: Richard Eisenberg; "Anselm Schüler (conversations subemail)"
> Cc: [hidden email]
> Subject: RE: Hi. I'm new to this mailing list and have a few questions.
>  
> Welcome Anselm.  ghc-devs is a very informal mailing list, and we welcome newcomers.
>  
> For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement
>  
> What Richard says is right, but you should feel free to fly the kite on this list if you want – or on Haskell Café – to get some idea of whether others seem warm about the idea, before writing a full proposal.  
>  
> Simon
>  
> From: ghc-devs <[hidden email]> On Behalf Of Richard Eisenberg
> Sent: 04 August 2020 16:05
> To: "Anselm Schüler (conversations subemail)" <[hidden email]>
> Cc: [hidden email]
> Subject: Re: Hi. I'm new to this mailing list and have a few questions.
>  
> Hi Anselm,
>  
> Welcome!
>  
> A good way of getting used to a list like this one is to wait a little while and observe what kind of messages others send; this will give you a feel for how the list is used. If you're impatient, you can also check out the archives at https://mail.haskell.org/pipermail/ghc-devs/.
>  
> As for a feature request: if your feature changes the language GHC accepts (most do), the right place to post is at https://github.com/ghc-proposals/ghc-proposals. There is a description of how to proceed on that page. Proposals submitted there get debated within the community and then eventually sent to a GHC Steering Committee for a vote on acceptance or rejection. Then, we worry about implementing it. If you have a suggestion that does not change the language GHC accepts, you can post an Issue at https://gitlab.haskell.org/ghc/ghc/.
>  
> I hope this is helpful!
> Richard
>  
>
> On Aug 4, 2020, at 8:59 AM, Anselm Schüler (conversations subemail) <[hidden email]> wrote:
>  
> First of all, in general, I’m new to mailing lists (as used for discussions) in general, so a question about that:
> When subscribed to the mailing list, do you get every message, or are some discussions hidden?
>  
> Second of all, I’d like to know what kinds of messages are appropriate here. I’m not familiar with coding compilers or anything of the like, so I’m somewhat afraid of offering unhelpful comments or being just woefully underqualified to participate here.
> For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement (that might be wrong). Is it alright if I submit that here or should I use some other forum?
>  
> Thank you in advance for the answers.
>  
> Anselm Schüler
> www.anselmschueler.com
> [hidden email]
> _______________________________________________
> ghc-devs mailing list
> [hidden email]
> http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
>  
>  
> _______________________________________________
> ghc-devs mailing list
> [hidden email]
> http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

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RE: AW: RE: Hi. I'm new to this mailing list and have a few questions.

Anselm Schüler (conversations subemail)
In reply to this post by Rowan Goemans

True, but this makes the type less readable since id @_ :: _ -> _.

 

Anselm Schüler

www.anselmschueler.com

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 19:59
To: [hidden email]
Subject: Re: AW: RE: Hi. I'm new to this mailing list and have a few questions.

 

Just as a heads up. You can achieve what you want already by doing:

f @_ @([String]) :: forall a. (a, [String]) -> ([String], a)

Best regards,

Rowan Goemans

On 8/4/20 7:45 PM, Anselm Schüler (conversations subemail) wrote:

Thank you for the nice introduction :) !

I will check out the GHC proposals site.

And following Simon’s (I hope addressing with first name is OK) suggestion, I’m going to give an outline of the idea.

 

The idea is to extend type application syntax to enable explicit assignment of types to specific type variables.

For instance, say I have f :: forall a b. (a, b) -> (b, a), and I want to apply the type [String] to it. My only option is to do

f @([String]) :: forall b. ([String], b) -> (b, [String])

—but what if, instead, I want a function of type forall a. (a, [String]) -> ([String], a)?

I propose the following syntax:

f @{b = [String]} :: forall a. ([String], b) -> (b, [String])

This wouldn’t break any existing programs since using record syntax here is already disallowed and met with an error message.

A question is of course the symbol used for assignment (~, =, ::, or ->?).

 

I hope the code shows up as a monospace font on your end. I used the IBM Plex Mono font, which is open-source.

 

Anselm Schüler

www.anselmschueler.com

[hidden email]

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 18:44
To: [hidden email]; [hidden email]
Cc: [hidden email]
Subject: RE: Hi. I'm new to this mailing list and have a few questions.

 

Welcome Anselm.  ghc-devs is a very informal mailing list, and we welcome newcomers.

 

For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement

 

What Richard says is right, but you should feel free to fly the kite on this list if you want – or on Haskell Café – to get some idea of whether others seem warm about the idea, before writing a full proposal. 

 

Simon

 

From: ghc-devs [hidden email] On Behalf Of Richard Eisenberg
Sent: 04 August 2020 16:05
To: "Anselm Schüler (conversations subemail)" [hidden email]
Cc: [hidden email]
Subject: Re: Hi. I'm new to this mailing list and have a few questions.

 

Hi Anselm,

 

Welcome!

 

A good way of getting used to a list like this one is to wait a little while and observe what kind of messages others send; this will give you a feel for how the list is used. If you're impatient, you can also check out the archives at https://mail.haskell.org/pipermail/ghc-devs/.

 

As for a feature request: if your feature changes the language GHC accepts (most do), the right place to post is at https://github.com/ghc-proposals/ghc-proposals. There is a description of how to proceed on that page. Proposals submitted there get debated within the community and then eventually sent to a GHC Steering Committee for a vote on acceptance or rejection. Then, we worry about implementing it. If you have a suggestion that does not change the language GHC accepts, you can post an Issue at https://gitlab.haskell.org/ghc/ghc/.

 

I hope this is helpful!

Richard

 

On Aug 4, 2020, at 8:59 AM, Anselm Schüler (conversations subemail) <[hidden email]> wrote:

 

First of all, in general, I’m new to mailing lists (as used for discussions) in general, so a question about that:

When subscribed to the mailing list, do you get every message, or are some discussions hidden?

 

Second of all, I’d like to know what kinds of messages are appropriate here. I’m not familiar with coding compilers or anything of the like, so I’m somewhat afraid of offering unhelpful comments or being just woefully underqualified to participate here.

For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement (that might be wrong). Is it alright if I submit that here or should I use some other forum?

 

Thank you in advance for the answers.

 

Anselm Schüler

_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

 

 



_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

 


_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
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RE: AW: RE: Hi. I'm new to this mailing list and have a few questions.

Anselm Schüler (conversations subemail)

And also, it’s really weird and seems like a feature that should be removed IMO. It kind of looks like the type variable _ is always in-scope, and it’s unclear if the type of the resulting function is just type variables without an explicit forall or if _ has a special meaning.

 

Anselm Schüler

www.anselmschueler.com

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 20:09
To: [hidden email]; [hidden email]
Subject: RE: AW: RE: Hi. I'm new to this mailing list and have a few questions.

 

True, but this makes the type less readable since id @_ :: _ -> _.

 

Anselm Schüler

www.anselmschueler.com

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 19:59
To: [hidden email]
Subject: Re: AW: RE: Hi. I'm new to this mailing list and have a few questions.

 

Just as a heads up. You can achieve what you want already by doing:

f @_ @([String]) :: forall a. (a, [String]) -> ([String], a)

Best regards,

Rowan Goemans

On 8/4/20 7:45 PM, Anselm Schüler (conversations subemail) wrote:

Thank you for the nice introduction :) !

I will check out the GHC proposals site.

And following Simon’s (I hope addressing with first name is OK) suggestion, I’m going to give an outline of the idea.

 

The idea is to extend type application syntax to enable explicit assignment of types to specific type variables.

For instance, say I have f :: forall a b. (a, b) -> (b, a), and I want to apply the type [String] to it. My only option is to do

f @([String]) :: forall b. ([String], b) -> (b, [String])

—but what if, instead, I want a function of type forall a. (a, [String]) -> ([String], a)?

I propose the following syntax:

f @{b = [String]} :: forall a. ([String], b) -> (b, [String])

This wouldn’t break any existing programs since using record syntax here is already disallowed and met with an error message.

A question is of course the symbol used for assignment (~, =, ::, or ->?).

 

I hope the code shows up as a monospace font on your end. I used the IBM Plex Mono font, which is open-source.

 

Anselm Schüler

wwwanselmschueler.com

[hidden email]

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 18:44
To: [hidden email]; [hidden email]
Cc: [hidden email]
Subject: RE: Hi. I'm new to this mailing list and have a few questions.

 

Welcome Anselm  ghc-devs is a very informal mailing list, and we welcome newcomers.

 

For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement

 

What Richard says is right, but you should feel free to fly the kite on this list if you want – or on Haskell Café – to get some idea of whether others seem warm about the idea, before writing a full proposal. 

 

Simon

 

From: ghc-devs [hidden email] On Behalf Of Richard Eisenberg
Sent: 04 August 2020 16:05
To: "Anselm Schüler (conversations subemail)" [hidden email]
Cc: [hidden email]
Subject: Re: Hi. I'm new to this mailing list and have a few questions.

 

Hi Anselm,

 

Welcome!

 

A good way of getting used to a list like this one is to wait a little while and observe what kind of messages others send; this will give you a feel for how the list is used. If you're impatient, you can also check out the archives at https://mail.haskell.org/pipermail/ghc-devs/.

 

As for a feature request: if your feature changes the language GHC accepts (most do), the right place to post is at https://githubcom/ghc-proposals/ghc-proposals. There is a description of how to proceed on that page. Proposals submitted there get debated within the community and then eventually sent to a GHC Steering Committee for a vote on acceptance or rejection. Then, we worry about implementing it. If you have a suggestion that does not change the language GHC accepts, you can post an Issue at https://gitlab.haskell.org/ghc/ghc/.

 

I hope this is helpful!

Richard

 

On Aug 4, 2020, at 8:59 AM, Anselm Schüler (conversations subemail) <[hidden email]> wrote:

 

First of all, in general, I’m new to mailing lists (as used for discussions) in general, so a question about that:

When subscribed to the mailing list, do you get every message, or are some discussions hidden?

 

Second of all, I’d like to know what kinds of messages are appropriate here. I’m not familiar with coding compilers or anything of the like, so I’m somewhat afraid of offering unhelpful comments or being just woefully underqualified to participate here.

For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement (that might be wrong). Is it alright if I submit that here or should I use some other forum?

 

Thank you in advance for the answers.

 

Anselm Schüler

_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

 

 

 

_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

 

 


_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
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Open this post in threaded view
|

Re: AW: RE: Hi. I'm new to this mailing list and have a few questions.

Brandon Allbery
_ already has the meaning of a type wildcard (generalized from its use as a wildcard in patterns), so this
is consistent with its use in other type signatures. The problem I see with your proposal is that it assumes
you know the names of the type variables in the original declaration.

On Tue, Aug 4, 2020 at 2:12 PM Anselm Schüler (conversations subemail) <[hidden email]> wrote:

And also, it’s really weird and seems like a feature that should be removed IMO. It kind of looks like the type variable _ is always in-scope, and it’s unclear if the type of the resulting function is just type variables without an explicit forall or if _ has a special meaning.

 

Anselm Schüler

www.anselmschueler.com

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 20:09
To: [hidden email]; [hidden email]
Subject: RE: AW: RE: Hi. I'm new to this mailing list and have a few questions.

 

True, but this makes the type less readable since id @_ :: _ -> _.

 

Anselm Schüler

www.anselmschueler.com

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 19:59
To: [hidden email]
Subject: Re: AW: RE: Hi. I'm new to this mailing list and have a few questions.

 

Just as a heads up. You can achieve what you want already by doing:

f @_ @([String]) :: forall a. (a, [String]) -> ([String], a)

Best regards,

Rowan Goemans

On 8/4/20 7:45 PM, Anselm Schüler (conversations subemail) wrote:

Thank you for the nice introduction :) !

I will check out the GHC proposals site.

And following Simon’s (I hope addressing with first name is OK) suggestion, I’m going to give an outline of the idea.

 

The idea is to extend type application syntax to enable explicit assignment of types to specific type variables.

For instance, say I have f :: forall a b. (a, b) -> (b, a), and I want to apply the type [String] to it. My only option is to do

f @([String]) :: forall b. ([String], b) -> (b, [String])

—but what if, instead, I want a function of type forall a. (a, [String]) -> ([String], a)?

I propose the following syntax:

f @{b = [String]} :: forall a. ([String], b) -> (b, [String])

This wouldn’t break any existing programs since using record syntax here is already disallowed and met with an error message.

A question is of course the symbol used for assignment (~, =, ::, or ->?).

 

I hope the code shows up as a monospace font on your end. I used the IBM Plex Mono font, which is open-source.

 

Anselm Schüler

wwwanselmschueler.com

[hidden email]

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 18:44
To: [hidden email]; [hidden email]
Cc: [hidden email]
Subject: RE: Hi. I'm new to this mailing list and have a few questions.

 

Welcome Anselm  ghc-devs is a very informal mailing list, and we welcome newcomers.

 

For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement

 

What Richard says is right, but you should feel free to fly the kite on this list if you want – or on Haskell Café – to get some idea of whether others seem warm about the idea, before writing a full proposal. 

 

Simon

 

From: ghc-devs [hidden email] On Behalf Of Richard Eisenberg
Sent: 04 August 2020 16:05
To: "Anselm Schüler (conversations subemail)" [hidden email]
Cc: [hidden email]
Subject: Re: Hi. I'm new to this mailing list and have a few questions.

 

Hi Anselm,

 

Welcome!

 

A good way of getting used to a list like this one is to wait a little while and observe what kind of messages others send; this will give you a feel for how the list is used. If you're impatient, you can also check out the archives at https://mail.haskell.org/pipermail/ghc-devs/.

 

As for a feature request: if your feature changes the language GHC accepts (most do), the right place to post is at https://githubcom/ghc-proposals/ghc-proposals. There is a description of how to proceed on that page. Proposals submitted there get debated within the community and then eventually sent to a GHC Steering Committee for a vote on acceptance or rejection. Then, we worry about implementing it. If you have a suggestion that does not change the language GHC accepts, you can post an Issue at https://gitlab.haskell.org/ghc/ghc/.

 

I hope this is helpful!

Richard

 

On Aug 4, 2020, at 8:59 AM, Anselm Schüler (conversations subemail) <[hidden email]> wrote:

 

First of all, in general, I’m new to mailing lists (as used for discussions) in general, so a question about that:

When subscribed to the mailing list, do you get every message, or are some discussions hidden?

 

Second of all, I’d like to know what kinds of messages are appropriate here. I’m not familiar with coding compilers or anything of the like, so I’m somewhat afraid of offering unhelpful comments or being just woefully underqualified to participate here.

For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement (that might be wrong). Is it alright if I submit that here or should I use some other forum?

 

Thank you in advance for the answers.

 

Anselm Schüler

_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

 

 

 

_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

 

 

_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs


--
brandon s allbery kf8nh

_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
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Open this post in threaded view
|

RE: AW: RE: Hi. I'm new to this mailing list and have a few questions.

Anselm Schüler (conversations subemail)

That’s true, but type wildcards without PartialTypeSignatures throw an error, while this doesn’t need that (which suggests that they’re represented differently internally — I don’t know, of course). Also, there are other drawbacks discussed in the ghc-proposals Proposal 0042-named-type-args that was mentioned by [hidden email]. Which is, I think, it seems, where the discussion should take place (?).

 

Anselm Schüler

www.anselmschueler.com

[hidden email]

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 20:16
To: [hidden email]
Cc: [hidden email]; [hidden email]
Subject: Re: AW: RE: Hi. I'm new to this mailing list and have a few questions.

 

_ already has the meaning of a type wildcard (generalized from its use as a wildcard in patterns), so this

is consistent with its use in other type signatures. The problem I see with your proposal is that it assumes

you know the names of the type variables in the original declaration.

 

On Tue, Aug 4, 2020 at 2:12 PM Anselm Schüler (conversations subemail) <[hidden email]> wrote:

And also, it’s really weird and seems like a feature that should be removed IMO. It kind of looks like the type variable _ is always in-scope, and it’s unclear if the type of the resulting function is just type variables without an explicit forall or if _ has a special meaning.

 

Anselm Schüler

www.anselmschueler.com

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 20:09
To: [hidden email]; [hidden email]
Subject: RE: AW: RE: Hi. I'm new to this mailing list and have a few questions.

 

True, but this makes the type less readable since id @_ :: _ -> _.

 

Anselm Schüler

www.anselmschueler.com

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 19:59
To: [hidden email]
Subject: Re: AW: RE: Hi. I'm new to this mailing list and have a few questions.

 

Just as a heads up. You can achieve what you want already by doing:

f @_ @([String]) :: forall a. (a, [String]) -> ([String], a)

Best regards,

Rowan Goemans

On 8/4/20 7:45 PM, Anselm Schüler (conversations subemail) wrote:

Thank you for the nice introduction :) !

I will check out the GHC proposals site.

And following Simon’s (I hope addressing with first name is OK) suggestion, I’m going to give an outline of the idea.

 

The idea is to extend type application syntax to enable explicit assignment of types to specific type variables.

For instance, say I have f :: forall a b. (a, b) -> (b, a), and I want to apply the type [String] to it. My only option is to do

f @([String]) :: forall b. ([String], b) -> (b, [String])

—but what if, instead, I want a function of type forall a. (a, [String]) -> ([String], a)?

I propose the following syntax:

f @{b = [String]} :: forall a. ([String], b) -> (b, [String])

This wouldn’t break any existing programs since using record syntax here is already disallowed and met with an error message.

A question is of course the symbol used for assignment (~, =, ::, or ->?).

 

I hope the code shows up as a monospace font on your end. I used the IBM Plex Mono font, which is open-source.

 

Anselm Schüler

wwwanselmschueler.com

[hidden email]

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 18:44
To: [hidden email]; [hidden email]
Cc: [hidden email]
Subject: RE: Hi. I'm new to this mailing list and have a few questions.

 

Welcome Anselm  ghc-devs is a very informal mailing list, and we welcome newcomers.

 

For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement

 

What Richard says is right, but you should feel free to fly the kite on this list if you want – or on Haskell Café – to get some idea of whether others seem warm about the idea, before writing a full proposal. 

 

Simon

 

From: ghc-devs [hidden email] On Behalf Of Richard Eisenberg
Sent: 04 August 2020 16:05
To: "Anselm Schüler (conversations subemail)" [hidden email]
Cc: [hidden email]
Subject: Re: Hi. I'm new to this mailing list and have a few questions.

 

Hi Anselm,

 

Welcome!

 

A good way of getting used to a list like this one is to wait a little while and observe what kind of messages others send; this will give you a feel for how the list is used. If you're impatient, you can also check out the archives at https://mail.haskell.org/pipermail/ghc-devs/.

 

As for a feature request: if your feature changes the language GHC accepts (most do), the right place to post is at https://githubcom/ghc-proposals/ghc-proposals. There is a description of how to proceed on that page. Proposals submitted there get debated within the community and then eventually sent to a GHC Steering Committee for a vote on acceptance or rejection. Then, we worry about implementing it. If you have a suggestion that does not change the language GHC accepts, you can post an Issue at https://gitlab.haskell.org/ghc/ghc/.

 

I hope this is helpful!

Richard

 

On Aug 4, 2020, at 8:59 AM, Anselm Schüler (conversations subemail) <[hidden email]> wrote:

 

First of all, in general, I’m new to mailing lists (as used for discussions) in general, so a question about that:

When subscribed to the mailing list, do you get every message, or are some discussions hidden?

 

Second of all, I’d like to know what kinds of messages are appropriate here. I’m not familiar with coding compilers or anything of the like, so I’m somewhat afraid of offering unhelpful comments or being just woefully underqualified to participate here.

For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement (that might be wrong). Is it alright if I submit that here or should I use some other forum?

 

Thank you in advance for the answers.

 

Anselm Schüler

_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

 

 

 

_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

 

 

_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs


 

--

brandon s allbery kf8nh

[hidden email]

 


_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
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Re: AW: RE: Hi. I'm new to this mailing list and have a few questions.

Brandon Allbery
It's represented the same way but handled differently; my point, though, was more about it being consistent with the rest of the language, which is less about how the compiler handles it than about how it looks to the programmer. In this case, _ is consistently used to mean a wildcard of some kind, even though it has to be handled by the compiler in multiple places including TypeApplications and PartialTypeSignatures (others include patterns, typed holes, and let bindings as an extension of simple patterns).

On Tue, Aug 4, 2020 at 2:27 PM Anselm Schüler (conversations subemail) <[hidden email]> wrote:

That’s true, but type wildcards without PartialTypeSignatures throw an error, while this doesn’t need that (which suggests that they’re represented differently internally — I don’t know, of course). Also, there are other drawbacks discussed in the ghc-proposals Proposal 0042-named-type-args that was mentioned by [hidden email]. Which is, I think, it seems, where the discussion should take place (?).

 

Anselm Schüler

www.anselmschueler.com

[hidden email]

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 20:16
To: [hidden email]
Cc: [hidden email]; [hidden email]
Subject: Re: AW: RE: Hi. I'm new to this mailing list and have a few questions.

 

_ already has the meaning of a type wildcard (generalized from its use as a wildcard in patterns), so this

is consistent with its use in other type signatures. The problem I see with your proposal is that it assumes

you know the names of the type variables in the original declaration.

 

On Tue, Aug 4, 2020 at 2:12 PM Anselm Schüler (conversations subemail) <[hidden email]> wrote:

And also, it’s really weird and seems like a feature that should be removed IMO. It kind of looks like the type variable _ is always in-scope, and it’s unclear if the type of the resulting function is just type variables without an explicit forall or if _ has a special meaning.

 

Anselm Schüler

www.anselmschueler.com

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 20:09
To: [hidden email]; [hidden email]
Subject: RE: AW: RE: Hi. I'm new to this mailing list and have a few questions.

 

True, but this makes the type less readable since id @_ :: _ -> _.

 

Anselm Schüler

www.anselmschueler.com

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 19:59
To: [hidden email]
Subject: Re: AW: RE: Hi. I'm new to this mailing list and have a few questions.

 

Just as a heads up. You can achieve what you want already by doing:

f @_ @([String]) :: forall a. (a, [String]) -> ([String], a)

Best regards,

Rowan Goemans

On 8/4/20 7:45 PM, Anselm Schüler (conversations subemail) wrote:

Thank you for the nice introduction :) !

I will check out the GHC proposals site.

And following Simon’s (I hope addressing with first name is OK) suggestion, I’m going to give an outline of the idea.

 

The idea is to extend type application syntax to enable explicit assignment of types to specific type variables.

For instance, say I have f :: forall a b. (a, b) -> (b, a), and I want to apply the type [String] to it. My only option is to do

f @([String]) :: forall b. ([String], b) -> (b, [String])

—but what if, instead, I want a function of type forall a. (a, [String]) -> ([String], a)?

I propose the following syntax:

f @{b = [String]} :: forall a. ([String], b) -> (b, [String])

This wouldn’t break any existing programs since using record syntax here is already disallowed and met with an error message.

A question is of course the symbol used for assignment (~, =, ::, or ->?).

 

I hope the code shows up as a monospace font on your end. I used the IBM Plex Mono font, which is open-source.

 

Anselm Schüler

wwwanselmschueler.com

[hidden email]

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 18:44
To: [hidden email]; [hidden email]
Cc: [hidden email]
Subject: RE: Hi. I'm new to this mailing list and have a few questions.

 

Welcome Anselm  ghc-devs is a very informal mailing list, and we welcome newcomers.

 

For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement

 

What Richard says is right, but you should feel free to fly the kite on this list if you want – or on Haskell Café – to get some idea of whether others seem warm about the idea, before writing a full proposal. 

 

Simon

 

From: ghc-devs [hidden email] On Behalf Of Richard Eisenberg
Sent: 04 August 2020 16:05
To: "Anselm Schüler (conversations subemail)" [hidden email]
Cc: [hidden email]
Subject: Re: Hi. I'm new to this mailing list and have a few questions.

 

Hi Anselm,

 

Welcome!

 

A good way of getting used to a list like this one is to wait a little while and observe what kind of messages others send; this will give you a feel for how the list is used. If you're impatient, you can also check out the archives at https://mail.haskell.org/pipermail/ghc-devs/.

 

As for a feature request: if your feature changes the language GHC accepts (most do), the right place to post is at https://githubcom/ghc-proposals/ghc-proposals. There is a description of how to proceed on that page. Proposals submitted there get debated within the community and then eventually sent to a GHC Steering Committee for a vote on acceptance or rejection. Then, we worry about implementing it. If you have a suggestion that does not change the language GHC accepts, you can post an Issue at https://gitlab.haskell.org/ghc/ghc/.

 

I hope this is helpful!

Richard

 

On Aug 4, 2020, at 8:59 AM, Anselm Schüler (conversations subemail) <[hidden email]> wrote:

 

First of all, in general, I’m new to mailing lists (as used for discussions) in general, so a question about that:

When subscribed to the mailing list, do you get every message, or are some discussions hidden?

 

Second of all, I’d like to know what kinds of messages are appropriate here. I’m not familiar with coding compilers or anything of the like, so I’m somewhat afraid of offering unhelpful comments or being just woefully underqualified to participate here.

For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement (that might be wrong). Is it alright if I submit that here or should I use some other forum?

 

Thank you in advance for the answers.

 

Anselm Schüler

_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

 

 

 

_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

 

 

_______________________________________________
ghc-devs mailing list
[hidden email]
http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs


 

--

brandon s allbery kf8nh

[hidden email]

 



--
brandon s allbery kf8nh

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Re: Hi. I'm new to this mailing list and have a few questions.

Richard Eisenberg-5
Your idea is a good one. To add to Iavor's mention about Cryptol, Agda uses both positional and named parameters, and they seem to have a good time with it.

To be honest, if I could go back in time, I would think much harder about the decision to do ordered parameters in GHC. I'm very sympathetic to this direction of travel, but unsure about the costs (code breakage, etc.) of doing so.

Do comment on the proposal thread, Anselm! :) We need motivated people like you to keep those conversations going.

Richard

PS: And, yes, I believe everyone here is on a casual, first-name basis.

On Aug 4, 2020, at 2:37 PM, Brandon Allbery <[hidden email]> wrote:

It's represented the same way but handled differently; my point, though, was more about it being consistent with the rest of the language, which is less about how the compiler handles it than about how it looks to the programmer. In this case, _ is consistently used to mean a wildcard of some kind, even though it has to be handled by the compiler in multiple places including TypeApplications and PartialTypeSignatures (others include patterns, typed holes, and let bindings as an extension of simple patterns).

On Tue, Aug 4, 2020 at 2:27 PM Anselm Schüler (conversations subemail) <[hidden email]> wrote:

That’s true, but type wildcards without PartialTypeSignatures throw an error, while this doesn’t need that (which suggests that they’re represented differently internally — I don’t know, of course). Also, there are other drawbacks discussed in the ghc-proposals Proposal 0042-named-type-args that was mentioned by [hidden email]. Which is, I think, it seems, where the discussion should take place (?).

 

Anselm Schüler

www.anselmschueler.com

[hidden email]

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 20:16
To: [hidden email]
Cc: [hidden email]; [hidden email]
Subject: Re: AW: RE: Hi. I'm new to this mailing list and have a few questions.

 

_ already has the meaning of a type wildcard (generalized from its use as a wildcard in patterns), so this

is consistent with its use in other type signatures. The problem I see with your proposal is that it assumes

you know the names of the type variables in the original declaration.

 

On Tue, Aug 4, 2020 at 2:12 PM Anselm Schüler (conversations subemail) <[hidden email]> wrote:

And also, it’s really weird and seems like a feature that should be removed IMO. It kind of looks like the type variable _ is always in-scope, and it’s unclear if the type of the resulting function is just type variables without an explicit forall or if _ has a special meaning.

 

Anselm Schüler

www.anselmschueler.com

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 20:09
To: [hidden email]; [hidden email]
Subject: RE: AW: RE: Hi. I'm new to this mailing list and have a few questions.

 

True, but this makes the type less readable since id @_ :: _ -> _.

 

Anselm Schüler

www.anselmschueler.com

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 19:59
To: [hidden email]
Subject: Re: AW: RE: Hi. I'm new to this mailing list and have a few questions.

 

Just as a heads up. You can achieve what you want already by doing:

f @_ @([String]) :: forall a. (a, [String]) -> ([String], a) 

Best regards,

Rowan Goemans

On 8/4/20 7:45 PM, Anselm Schüler (conversations subemail) wrote:

Thank you for the nice introduction :) !

I will check out the GHC proposals site.

And following Simon’s (I hope addressing with first name is OK) suggestion, I’m going to give an outline of the idea.

 

The idea is to extend type application syntax to enable explicit assignment of types to specific type variables.

For instance, say I have f :: forall a b. (a, b) -> (b, a), and I want to apply the type [String] to it. My only option is to do

f @([String]) :: forall b. ([String], b) -> (b, [String]) 

—but what if, instead, I want a function of type forall a. (a, [String]) -> ([String], a)?

I propose the following syntax:

f @{b = [String]} :: forall a. ([String], b) -> (b, [String])

This wouldn’t break any existing programs since using record syntax here is already disallowed and met with an error message.

A question is of course the symbol used for assignment (~, =, ::, or ->?).

 

I hope the code shows up as a monospace font on your end. I used the IBM Plex Mono font, which is open-source.

 

Anselm Schüler

wwwanselmschueler.com

[hidden email]

 

From: [hidden email]
Sent: Tuesday, August 4, 2020 18:44
To: [hidden email]; [hidden email]
Cc: [hidden email]
Subject: RE: Hi. I'm new to this mailing list and have a few questions.

 

Welcome Anselm  ghc-devs is a very informal mailing list, and we welcome newcomers.

 

For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement

 

What Richard says is right, but you should feel free to fly the kite on this list if you want – or on Haskell Café – to get some idea of whether others seem warm about the idea, before writing a full proposal.  

 

Simon

 

From: ghc-devs [hidden email] On Behalf Of Richard Eisenberg
Sent: 04 August 2020 16:05
To: "Anselm Schüler (conversations subemail)" [hidden email]
Cc: [hidden email]
Subject: Re: Hi. I'm new to this mailing list and have a few questions.

 

Hi Anselm,

 

Welcome!

 

A good way of getting used to a list like this one is to wait a little while and observe what kind of messages others send; this will give you a feel for how the list is used. If you're impatient, you can also check out the archives at https://mail.haskell.org/pipermail/ghc-devs/.

 

As for a feature request: if your feature changes the language GHC accepts (most do), the right place to post is at https://githubcom/ghc-proposals/ghc-proposals. There is a description of how to proceed on that page. Proposals submitted there get debated within the community and then eventually sent to a GHC Steering Committee for a vote on acceptance or rejection. Then, we worry about implementing it. If you have a suggestion that does not change the language GHC accepts, you can post an Issue at https://gitlab.haskell.org/ghc/ghc/.

 

I hope this is helpful!

Richard

 

On Aug 4, 2020, at 8:59 AM, Anselm Schüler (conversations subemail) <[hidden email]> wrote:

 

First of all, in general, I’m new to mailing lists (as used for discussions) in general, so a question about that:

When subscribed to the mailing list, do you get every message, or are some discussions hidden?

 

Second of all, I’d like to know what kinds of messages are appropriate here. I’m not familiar with coding compilers or anything of the like, so I’m somewhat afraid of offering unhelpful comments or being just woefully underqualified to participate here.

For example, I have a feature idea in the back of my mind, which I imagine would be easy to implement (that might be wrong). Is it alright if I submit that here or should I use some other forum?

 

Thank you in advance for the answers.

 

Anselm Schüler

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brandon s allbery kf8nh

[hidden email]

 



-- 
brandon s allbery kf8nh
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[hidden email]
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