Context for typed holes

David Feuer

8 Oct 2015 8 Oct '15

7:25 p.m.

Unless something has changed really recently that I've missed, the typed holes messages are missing some really important information: instance information for types in scope. When I am trying to fill in a hole, I look to the "relevant bindings" to show me what pieces I have available to use. Those pieces don't include contexts! Is there something fundamentally hard about adding this information? I'd only want instance information for type variables--providing it for concrete types would make too much noise. I'd also want information on equality constraints, of course.

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Manuel M T Chakravarty

22 Oct 22 Oct

7:15 p.m.

I think, this is a good point. Maybe you should make a ticket for it. Manuel

...

David Feuer :

Unless something has changed really recently that I've missed, the typed holes messages are missing some really important information: instance information for types in scope. When I am trying to fill in a hole, I look to the "relevant bindings" to show me what pieces I have available to use. Those pieces don't include contexts! Is there something fundamentally hard about adding this information? I'd only want instance information for type variables--providing it for concrete types would make too much noise. I'd also want information on equality constraints, of course.

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Andres Löh

23 Oct 23 Oct

1:28 a.m.

Hi. On Oct 23, 2015 01:15, "Manuel M T Chakravarty" wrote:

...

I think, this is a good point. Maybe you should make a ticket for it.

#9479, I think. Cheers, Andres

...

...
David Feuer :

Unless something has changed really recently that I've missed, the typed holes messages are missing some really important information: instance information for types in scope. When I am trying to fill in a hole, I look to the "relevant bindings" to show me what pieces I have available to use. Those pieces don't include contexts! Is there something fundamentally hard about adding this information? I'd only want instance information for type variables--providing it for concrete types would make too much noise. I'd also want information on equality constraints, of course.

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David Feuer

1:48 a.m.

I opened https://ghc.haskell.org/trac/ghc/ticket/10954 for this. #9479, by Dominique Devriese, is complementary--she wants instance information for a *hole* with an ambiguous type. On Oct 23, 2015 1:28 AM, "Andres Löh" wrote:

...

Hi.

On Oct 23, 2015 01:15, "Manuel M T Chakravarty" wrote:

...
I think, this is a good point. Maybe you should make a ticket for it.

#9479, I think.

Cheers, Andres

...
...
David Feuer :

Unless something has changed really recently that I've missed, the typed holes messages are missing some really important information: instance information for types in scope. When I am trying to fill in a hole, I look to the "relevant bindings" to show me what pieces I have available to use. Those pieces don't include contexts! Is there something fundamentally hard about adding this information? I'd only want instance information for type variables--providing it for concrete types would make too much noise. I'd also want information on equality constraints, of course.

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Andres Löh

1:55 a.m.

Actually, #9091 was the one I was really looking for ... reported by me. See also the discussion about "given" vs. "wanted" constraints. Cheers, Andres On Fri, Oct 23, 2015 at 7:48 AM, David Feuer wrote:

...

I opened https://ghc.haskell.org/trac/ghc/ticket/10954 for this. #9479, by Dominique Devriese, is complementary--she wants instance information for a *hole* with an ambiguous type.

On Oct 23, 2015 1:28 AM, "Andres Löh" wrote:

...
Hi.

On Oct 23, 2015 01:15, "Manuel M T Chakravarty" wrote:

...
I think, this is a good point. Maybe you should make a ticket for it.

#9479, I think.

Cheers, Andres

...
...
David Feuer :

Unless something has changed really recently that I've missed, the typed holes messages are missing some really important information: instance information for types in scope. When I am trying to fill in a hole, I look to the "relevant bindings" to show me what pieces I have available to use. Those pieces don't include contexts! Is there something fundamentally hard about adding this information? I'd only want instance information for type variables--providing it for concrete types would make too much noise. I'd also want information on equality constraints, of course.

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

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David Feuer

1:59 a.m.

I just closed mine as a duplicate of yours. On Oct 23, 2015 1:55 AM, "Andres Löh" wrote:

...

Actually, #9091 was the one I was really looking for ... reported by me. See also the discussion about "given" vs. "wanted" constraints.

Cheers, Andres

On Fri, Oct 23, 2015 at 7:48 AM, David Feuer wrote:

...
I opened https://ghc.haskell.org/trac/ghc/ticket/10954 for this. #9479, by Dominique Devriese, is complementary--she wants instance information for a *hole* with an ambiguous type.

On Oct 23, 2015 1:28 AM, "Andres Löh" wrote:

...
Hi.

On Oct 23, 2015 01:15, "Manuel M T Chakravarty" wrote:

...
I think, this is a good point. Maybe you should make a ticket for it.

#9479, I think.

Cheers, Andres

...
...
David Feuer :

Unless something has changed really recently that I've missed, the typed holes messages are missing some really important information:

instance

...
...
...
information for types in scope. When I am trying to fill in a hole, I look to the "relevant bindings" to show me what pieces I have available to use. Those pieces don't include contexts! Is there something fundamentally hard about adding this information? I'd only want instance information for type variables--providing it for concrete types would make too much noise. I'd also want information on equality constraints, of course.

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Simon Peyton Jones

3:22 a.m.

Indeed. Please also do give concrete examples, so that we all talk about the same proposal. Simon From: ghc-devs [mailto:ghc-devs-bounces@haskell.org] On Behalf Of Manuel M T Chakravarty Sent: 23 October 2015 00:16 To: David Feuer Cc: ghc-devs Subject: Re: Context for typed holes I think, this is a good point. Maybe you should make a ticket for it. Manuel David Feuer mailto:david.feuer@gmail.com>: Unless something has changed really recently that I've missed, the typed holes messages are missing some really important information: instance information for types in scope. When I am trying to fill in a hole, I look to the "relevant bindings" to show me what pieces I have available to use. Those pieces don't include contexts! Is there something fundamentally hard about adding this information? I'd only want instance information for type variables--providing it for concrete types would make too much noise. I'd also want information on equality constraints, of course. _______________________________________________ ghc-devs mailing list ghc-devs@haskell.orgmailto:ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

Christopher Allen

1:35 a.m.

It's not just you. That's why I didn't mention holes in the book as people suggested. It's not just confusing for new people - it drives me nuts every time I use a hole in non-trivial code at work. On Thu, Oct 8, 2015 at 6:25 PM, David Feuer wrote:

...

Unless something has changed really recently that I've missed, the typed holes messages are missing some really important information: instance information for types in scope. When I am trying to fill in a hole, I look to the "relevant bindings" to show me what pieces I have available to use. Those pieces don't include contexts! Is there something fundamentally hard about adding this information? I'd only want instance information for type variables--providing it for concrete types would make too much noise. I'd also want information on equality constraints, of course.

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-- Chris Allen Currently working on http://haskellbook.com

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Andres Löh
Christopher Allen
David Feuer
Manuel M T Chakravarty
Simon Peyton Jones

Context for typed holes

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