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swap minView/maxView return value.
by Jean-Philippe Bernardy 13 Feb '07

13 Feb '07

Some time ago (before ghc 6.6 / base 2.0 release), I introduced minView and maxView in Data.Set and Data.Map (at a user's request). I agreed with Robert Dockins to implement the same functionality as in his version of the Edison library. Unfortunately, I uselessly swapped the return values of minView and maxView, introducing a difference both with the corresponding functions in the edison library and similar functions in Data.Map/Set. I propose to restore the symmetry, at the cost of incompatibility. The incompatibility is probably acceptable because the functions are still short-lived. See the trac ticket for details. http://hackage.haskell.org/trac/ghc/ticket/1134 I provide no patch nor QuickCheck properties because of the triviality of the change. Cheers, JP.

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Proposal: add extra readline completion functionality
by Judah Jacobson 12 Feb '07

12 Feb '07

I propose adding some functionality to the readline package (really just wrappers of variables from that library) which is necessary to fix ghci bug #998. See the proposed patch at http://hackage.haskell.org/trac/ghc/ticket/1141 as well as the bug report at http://hackage.haskell.org/trac/ghc/ticket/998 The main addition is rl_completion_word_break_hook, which lets us change the set of word break characters based on the context of the line. Specifically for ghci, this is needed to change whether "/" is a word boundary (depending on whether we're expanding a Haskell name or a filename). Note that this variable is only present in readline version 5.0 or later; I've put in some ifdef's to support compiling against older versions. I've also included get/set functions for the rl_attempted_completion_over variable. If it's set to nonzero, readline won't use its default completer when our custom completer returns no results. Thanks, -Judah

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Proposal: Data.Proxy
by Musasabi 09 Feb '07

09 Feb '07

Hello I propose a module called Data.Proxy into the base package containing the common Proxy type used in many different libraries (e.g. HAppS, HList, ...). Attached is the source code. - Einar Karttunen

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Re: Proposal: Make StateT in mtl lazy
by Yitzchak Gale 09 Feb '07

09 Feb '07

Ian Lynagh wrote: > > Control.Monad.State.Class -- for the MonadState class > > Control.Monad.State.Lazy > > Control.Monad.State.Strict > > Control.Monad.State -- re-exports .Class and .Lazy > > Now done. Wonderful news! Thanks! -Yitz

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[Fwd: Re: [GHC] #1134: swap minView/maxView return value]
by Christian Maeder 07 Feb '07

07 Feb '07

It should be allowed to fix a buggy interface (before the bug becomes a feature) Christian -------- Original-Nachricht -------- Betreff: Re: [GHC] #1134: swap minView/maxView return value Datum: Tue, 06 Feb 2007 23:59:25 -0000 Von: GHC <trac(a)galois.com> Antwort an: glasgow-haskell-bugs(a)haskell.org An: glasgow-haskell-bugs(a)haskell.org Newsgruppen: gmane.comp.lang.haskell.glasgow.bugs Referenzen: <071.1d16a01fab839e0adc11599f4864434e@localhost> #1134: swap minView/maxView return value ----------------------------+----------------------------------------------- Reporter: jpbernardy | Owner: jpbernardy Type: proposal | Status: new Priority: normal | Milestone: 6.8 Component: libraries/base | Version: 6.6 Severity: normal | Resolution: Keywords: collections | Difficulty: Easy (1 hr) Testcase: | Architecture: Unknown Os: Unknown | ----------------------------+----------------------------------------------- Changes (by igloo): * milestone: 6.6.1 => 6.8 * type: bug => proposal Comment: Unfortunately fixing this for 6.6.1 would mean changing the interface, which we don't allow within a stable branch. -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1134> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Compiling module using Data.Time with -O fails; can't find HsTime.h
by Alistair Bayley 06 Feb '07

06 Feb '07

If I try to compile this Main.hs: module Main where import Data.Time main = getCurrentTime >>= print with this ghc-6.6 command: ghc --make Main -o test -O ... I get this error: C:\DOCUME~1\bayleya\LOCALS~1\Temp\ghc728_0\ghc728_0.hc:8:20: HsTime.h: No such file or directory Is this me doing something I shouldn't, or is there something wrong with the way the library has been distributed? Alistair

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Adding binarySize to Binary
by Musasabi 06 Feb '07

06 Feb '07

Hello I keep wanting something like: binarySize :: Binary a => Proxy a -> (Int,Maybe Int) in the Data.Binary for returning the minimum and maximum (or Nothing for infinite) space requirements for objects of a given type. Proxy is just defined as "data Proxy t = Proxy", but omitting it is also possible. Would other people consider this an useful addition? - Einar Karttunen

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Proposal: Make StateT in mtl lazy
by Ian Lynagh 05 Feb '07

05 Feb '07

http://hackage.haskell.org/trac/ghc/ticket/1127 Deadline: 28 February 2007. I propose we make StateT lazy, as I suspect was the intention all along and as has been discussed (without reaching a conclusion) before. The patch is simply (in the definition of (>>=)): hunk ./Control/Monad/State.hs 195 - (a, s') <- runStateT m s + ~(a, s') <- runStateT m s Thanks Ian

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Paramorphisms / Data.Scanable?
by Jim Apple 04 Feb '07

04 Feb '07

I understand that it may not be possible to give simple types to anamorphisms or hylomorphisms, but I don't see there can't be a Data.Scannable with paramorphisms. class Scannable t where scanr :: (a -> b -> b) -> b -> t a -> t b scanl :: (a -> b -> a) -> a -> t b -> t a scanr1 :: (a -> a -> a) -> t a -> t a scanl1 :: (a -> a -> a) -> t a -> t a Jim

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Catamorphisms for arrows?
by Jim Apple 04 Feb '07

04 Feb '07

Could Data.Foldable be extended to function types by way of Bananas in Space: Extending Fold and Unfold to Exponential Types [1][2] or Boxes Go Bananas: Encoding Higher-Order Abstract Syntax with Parametric Polymorphism [3][4]? 1. http://citeseer.ist.psu.edu/293490.html 2. http://www.cs.nott.ac.uk/~gmh//bananas.ps 3. http://repository.upenn.edu/cis_reports/43/ 4. http://www.seas.upenn.edu/%7Esweirich/abstracts.html#washburn+:bgb-journal Jim

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