Why do you want this? The danger I see lurking is that you might find two RdrNames that give the same answer to getUnique but represent different Yes, that's exactly my concern.

Why do you want this? I'm working on #7282 - RebindableSyntax and Arrows. Here's a snippet from desugaring of arrow notation:

leaves = concatMap leavesMatch matches where leavesMatch :: LMatch Id (Located (body Id)) -> [(Located (body Id), IdSet)] leavesMatch (L _ (Match pats _ (GRHSs grhss binds))) = let defined_vars = mkVarSet (collectPatsBinders pats) `unionVarSet` mkVarSet (collectLocalBinders binds) in [(body, mkVarSet (collectLStmtsBinders stmts) `unionVarSet` defined_vars) | L _ (GRHS stmts body) <- grhss] This is in the desugarer. But I need to also know `length leaves` at the renaming stage, which means I need to call `concatMap leavesMatch matches`. The problem is that in the renamer my datatypes are not parametrised by `Id`. I turned `Id` into a type parameter `id`, but then I can't use VarSets. I could use more general UniqueSets but only if `id` type parameter is an instance of Uniquable. And since in the renamer the datatypes are parametrized with RdrName this leads me to wanting Uniqable RdrName instance. Janek

would making arrow remindable involve dropping the arr == haksell functions assumption or doing something that would allow generalized arrows? On Mon, Jun 16, 2014 at 5:14 PM, Nicolas Frisby wrote:

FYI it's #7828, not #7282.

Jan, I'm very glad you're working on this. Thanks!

On Mon, Jun 16, 2014 at 2:33 PM, Jan Stolarek wrote:

...

...

Why do you want this? The danger I see lurking is that you might find two RdrNames that give the same answer to getUnique but represent different Yes, that's exactly my concern.

...

Why do you want this? I'm working on #7282 - RebindableSyntax and Arrows. Here's a snippet from desugaring of arrow notation:

leaves = concatMap leavesMatch matches where leavesMatch :: LMatch Id (Located (body Id)) -> [(Located (body Id), IdSet)] leavesMatch (L _ (Match pats _ (GRHSs grhss binds))) = let defined_vars = mkVarSet (collectPatsBinders pats) `unionVarSet` mkVarSet (collectLocalBinders binds) in [(body, mkVarSet (collectLStmtsBinders stmts) `unionVarSet` defined_vars) | L _ (GRHS stmts body) <- grhss]

This is in the desugarer. But I need to also know `length leaves` at the renaming stage, which means I need to call `concatMap leavesMatch matches`. The problem is that in the renamer my datatypes are not parametrised by `Id`. I turned `Id` into a type parameter `id`, but then I can't use VarSets. I could use more general UniqueSets but only if `id` type parameter is an instance of Uniquable. And since in the renamer the datatypes are parametrized with RdrName this leads me to wanting Uniqable RdrName instance.

Janek _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://www.haskell.org/mailman/listinfo/ghc-devs

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So, without really trying to understand the code, what you are saying is this: you want a finite map from RdrNames. That seems sensible enough, if the domain elements all appear in the same scope in the Haskell source. I don't have enough perspective to say whether a Uniquable instance is the way to get to a finite map here. Richard On Jun 16, 2014, at 3:33 PM, Jan Stolarek wrote:

...

Why do you want this? The danger I see lurking is that you might find two RdrNames that give the same answer to getUnique but represent different Yes, that's exactly my concern.

...

Why do you want this? I'm working on #7282 - RebindableSyntax and Arrows. Here's a snippet from desugaring of arrow notation:

leaves = concatMap leavesMatch matches where leavesMatch :: LMatch Id (Located (body Id)) -> [(Located (body Id), IdSet)] leavesMatch (L _ (Match pats _ (GRHSs grhss binds))) = let defined_vars = mkVarSet (collectPatsBinders pats) `unionVarSet` mkVarSet (collectLocalBinders binds) in [(body, mkVarSet (collectLStmtsBinders stmts) `unionVarSet` defined_vars) | L _ (GRHS stmts body) <- grhss]

This is in the desugarer. But I need to also know `length leaves` at the renaming stage, which means I need to call `concatMap leavesMatch matches`. The problem is that in the renamer my datatypes are not parametrised by `Id`. I turned `Id` into a type parameter `id`, but then I can't use VarSets. I could use more general UniqueSets but only if `id` type parameter is an instance of Uniquable. And since in the renamer the datatypes are parametrized with RdrName this leads me to wanting Uniqable RdrName instance.

Janek

On 17/06/14 20:53, Simon Peyton Jones wrote:

I would require a lot of convincing that we wanted Uniques for RdrNames. I seriously doubt that, once the dust has settled, you'll need a finite map indexed by RdrNames. But even if you do, you could use a TrieMap-like structure.

I must be missing something... but what's wrong with Map RdrName? Cheers, Simon

Simon

| -----Original Message----- | From: ghc-devs [mailto:ghc-devs-bounces@haskell.org] On Behalf Of Richard | Eisenberg | Sent: 17 June 2014 15:01 | To: Jan Stolarek | Cc: ghc-devs@haskell.org | Subject: Re: Uniquable RdrName instance | | So, without really trying to understand the code, what you are saying is | this: you want a finite map from RdrNames. That seems sensible enough, if | the domain elements all appear in the same scope in the Haskell source. I | don't have enough perspective to say whether a Uniquable instance is the | way to get to a finite map here. | | Richard | | On Jun 16, 2014, at 3:33 PM, Jan Stolarek wrote: | | >> Why do you want this? The danger I see lurking is that you might find | two | >> RdrNames that give the same answer to getUnique but represent | different | > Yes, that's exactly my concern. | > | >> Why do you want this? | > I'm working on #7282 - RebindableSyntax and Arrows. Here's a snippet | from desugaring of arrow | > notation: | > | > leaves = concatMap leavesMatch matches | > where | > leavesMatch :: LMatch Id (Located (body Id)) -> [(Located (body Id), | IdSet)] | > leavesMatch (L _ (Match pats _ (GRHSs grhss binds))) | > = let defined_vars = mkVarSet (collectPatsBinders pats) | `unionVarSet` | > mkVarSet (collectLocalBinders | binds) | > in [(body, mkVarSet (collectLStmtsBinders stmts) | `unionVarSet` defined_vars) | L _ | > (GRHS stmts body) <- grhss] | > | > This is in the desugarer. But I need to also know `length leaves` at | the renaming stage, which | > means I need to call `concatMap leavesMatch matches`. The problem is | that in the renamer my | > datatypes are not parametrised by `Id`. I turned `Id` into a type | parameter `id`, but then I | > can't use VarSets. I could use more general UniqueSets but only if `id` | type parameter is an | > instance of Uniquable. And since in the renamer the datatypes are | parametrized with RdrName this | > leads me to wanting Uniqable RdrName instance. | > | > Janek | | _______________________________________________ | ghc-devs mailing list | ghc-devs@haskell.org | http://www.haskell.org/mailman/listinfo/ghc-devs _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://www.haskell.org/mailman/listinfo/ghc-devs