April 2015 - Glasgow-haskell-users

skip hpc during build
by Jeremy 06 Apr '15

06 Apr '15

I'm deleting hpc after building ghc for a vm to save space. Is there an easy way to skip building it in the first place? -- View this message in context: http://haskell.1045720.n5.nabble.com/skip-hpc-during-build-tp5768327.html Sent from the Haskell - Glasgow-haskell-users mailing list archive at Nabble.com.

1 0

Functional dependencies conflict
by Daniel Trstenjak 05 Apr '15

05 Apr '15

Hi, I'm getting the compile error: Gamgine/Image/PNG/Internal/Parser.hs:14:10: Functional dependencies conflict between instance declarations: instance Monad m => Stream LB.ByteString m Word8 -- Defined at Gamgine/Image/PNG/Internal/Parser.hs:14:10 instance Monad m => Stream LB.ByteString m Char -- Defined in ‘Text.Parsec.Prim’ The relevant stuff from the parsec 3.1.9 code[1] is: {-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies, FlexibleContexts, UndecidableInstances #-} ... import qualified Data.ByteString.Lazy.Char8 as CL import qualified Data.ByteString.Char8 as C ... class (Monad m) => Stream s m t | s -> t where uncons :: s -> m (Maybe (t,s)) instance (Monad m) => Stream CL.ByteString m Char where uncons = return . CL.uncons instance (Monad m) => Stream C.ByteString m Char where uncons = return . C.uncons And from my code[2] is: {-# LANGUAGE BangPatterns, FlexibleInstances, MultiParamTypeClasses, FlexibleContexts #-} ... import qualified Data.ByteString.Lazy as LB ... instance (Monad m) => Stream LB.ByteString m Word8 where uncons = return . LB.uncons As you can see, the instances are for different ByteString types, therefore I don't quite get where GHC sees here any conflicts. Greetings, Daniel [1] https://github.com/aslatter/parsec/blob/master/Text/Parsec/Prim.hs [2] https://github.com/dan-t/Gamgine/blob/master/Gamgine/Image/PNG/Internal/Par…

2 3

Re: [Haskell-cafe] Functional dependencies conflict
by Roman Cheplyaka 05 Apr '15

05 Apr '15

To be precise, the sets of instances differ. Eg. the Char8 module exports the IsString instance, which normal Data.ByteString.Lazy doesn't. On 05/04/15 15:25, Ivan Lazar Miljenovic wrote: > On 5 April 2015 at 22:25, Roman Cheplyaka <roma(a)ro-che.info> wrote: >> Data.ByteString.Lazy.Char8 exports the same lazy bytestring type as >> Data.ByteString.Lazy. Only functions and instances differ. > > Well, *instances* can't differ... > >> >> On 05/04/15 15:19, Daniel Trstenjak wrote: >>> >>> Hi, >>> >>> I'm getting the compile error: >>> >>> Gamgine/Image/PNG/Internal/Parser.hs:14:10: >>> Functional dependencies conflict between instance declarations: >>> instance Monad m => Stream LB.ByteString m Word8 >>> -- Defined at Gamgine/Image/PNG/Internal/Parser.hs:14:10 >>> instance Monad m => Stream LB.ByteString m Char >>> -- Defined in ‘Text.Parsec.Prim’ >>> >>> >>> >>> The relevant stuff from the parsec 3.1.9 code[1] is: >>> >>> {-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies, FlexibleContexts, UndecidableInstances #-} >>> >>> ... >>> >>> import qualified Data.ByteString.Lazy.Char8 as CL >>> import qualified Data.ByteString.Char8 as C >>> >>> ... >>> >>> class (Monad m) => Stream s m t | s -> t where >>> uncons :: s -> m (Maybe (t,s)) >>> >>> instance (Monad m) => Stream CL.ByteString m Char where >>> uncons = return . CL.uncons >>> >>> instance (Monad m) => Stream C.ByteString m Char where >>> uncons = return . C.uncons >>> >>> >>> >>> And from my code[2] is: >>> >>> {-# LANGUAGE BangPatterns, FlexibleInstances, MultiParamTypeClasses, FlexibleContexts #-} >>> >>> ... >>> >>> import qualified Data.ByteString.Lazy as LB >>> >>> ... >>> >>> instance (Monad m) => Stream LB.ByteString m Word8 where >>> uncons = return . LB.uncons >>> >>> >>> >>> As you can see, the instances are for different ByteString types, >>> therefore I don't quite get where GHC sees here any conflicts. >>> >>> >>> Greetings, >>> Daniel >>> >>> >>> [1] https://github.com/aslatter/parsec/blob/master/Text/Parsec/Prim.hs >>> [2] https://github.com/dan-t/Gamgine/blob/master/Gamgine/Image/PNG/Internal/Par… >>> _______________________________________________ >>> Haskell-Cafe mailing list >>> Haskell-Cafe(a)haskell.org >>> http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe >>> >> >> _______________________________________________ >> Haskell-Cafe mailing list >> Haskell-Cafe(a)haskell.org >> http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe > > >

1 0

Help wanted: working on the GHC webpage
by Austin Seipp 03 Apr '15

03 Apr '15

Hello *, For a while now, I've been wanting to do a facelift on the GHC homepage, but among many other things it's been a low priority. I'd like for people to help, so I've tried to get the ball rolling. The webpages existed in a Darcs repository previously (which wasn't available online), but earlier today I converted them to a git repository which you can find here: https://github.com/haskell-infra/ghc-homepage The site is currently composed of a set of "server side include" files that have a crude form of HTML templating. So it's mostly just pretty verbose to add or refactor anything, and the sites templating and styling is quite old (it dates back at least 10 years!) So, I'm making an official call for some help. At the very least, I'd like to at least end up converting the site to something like Hakyll which is doable without me causing a lot of damage to the stylesheets, but for the actual page itself I'd really appreciate it if anyone could help out! Please send pull requests or file issues, it's much appreciated. -- Regards, Austin Seipp, Haskell Consultant Well-Typed LLP, http://www.well-typed.com/

1 0

immortal profiling
by Mark Wotton 03 Apr '15

03 Apr '15

https://ghc.haskell.org/trac/ghc/ticket/10235#ticket Would be really useful to be able to profile code without dying, especially in the context of a long-lived server. Am I missing something that would allow me to do this? cheers mark

2 1

Re: [Haskell-cafe] Parallel Profiling
by Dominic Steinitz 02 Apr '15

02 Apr '15

Hi Amos, Thanks very much - I am taking a look. Dominic Steinitz dominic(a)steinitz.org http://idontgetoutmuch.wordpress.com On 30 Mar 2015, at 22:05, Amos Robinson <amos.robinson(a)gmail.com> wrote: > Hi Dominic, > > A few years ago we wrote a program for analysing DPH runs, dph-event-seer. It provides a few general analyses like percent of time with N threads running, time between wake-ups etc. You might find it interesting, but I haven't actually looked at ghc-events-analyse, so I don't know what it provides. > > I'm sorry, but to compile it without DPH you'd have to modify it to remove DphOps*. > > https://github.com/ghc/packages-dph/blob/master/dph-event-seer/src/Main.hs > > Amos > > On Tue, 31 Mar 2015 at 04:38 Dominic Steinitz <dominic(a)steinitz.org> wrote: > Does anyone know of any tools for analysing parallel program performance? > > I am trying to use threadscope but it keeps crashing with my 100M log file and ghc-events-analyze is not going to help as I have many hundreds of threads all carrying out the same computation. I think I’d like a library that would allow me to construct my own analyses rather than display them via GTK. There is ghc-events but that seems to be just for parsing the logs and I couldn’t find anything that used it in the way I would like to (apart from threadscope and ghc-events-analyze of course). > > Thanks > > Dominic Steinitz > dominic(a)steinitz.org > http://idontgetoutmuch.wordpress.com > > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe(a)haskell.org > http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe

1 0