Re: [Haskell-cafe] Weird interaction between literate haskell, ghci and OverloadedStrings
Hi, Am Samstag, den 03.12.2011, 16:18 +1100 schrieb Erik de Castro Lopo: I'm working on a literate haskell document (actually TeX, but the example below is just test) and I'm using ByteStrings in the code. I know I can do: ghci -XOverloadedStrings file.lhs or, after ghci is running I can do: Main :set -XOverloadedStrings but I'd like to embed a directive in the file so that when loaded in GHCi, I will automatically get OverloadedStrings. This is mainly so that it JustWorks(tm) when I pass the file on to someone else. Is there a way to do this? There is a short example file below. I'm using ghc-7.0.4 from Debian testing. it does not seem to be related to literate haskell, if I copy the code from your file into a .hs without the , ghci still does not activate the OverloadedStrings extension when loading the file. I’d consider this a bug until the developers explain why this should or cannot be different, and suggest you file it as such. Greetings, Joachim -- Joachim nomeata Breitner m...@joachim-breitner.de | nome...@debian.org | GPG: 0x4743206C xmpp: nome...@joachim-breitner.de | http://www.joachim-breitner.de/ signature.asc Description: This is a digitally signed message part ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Weird interaction between literate haskell, ghci and OverloadedStrings
Joachim Breitner wrote: it does not seem to be related to literate haskell, if I copy the code from your file into a .hs without the , ghci still does not activate the OverloadedStrings extension when loading the file. I hadn't noticed that. I’d consider this a bug until the developers explain why this should or cannot be different, and suggest you file it as such. I agree. I've lodged a bug report here: http://hackage.haskell.org/trac/ghc/ticket/5673 Erik -- -- Erik de Castro Lopo http://www.mega-nerd.com/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Weird interaction between literate haskell, ghci and OverloadedStrings
On 3 December 2011 11:19, Erik de Castro Lopo mle...@mega-nerd.com wrote:
Joachim Breitner wrote:
it does not seem to be related to literate haskell, if I copy the code
from your file into a .hs without the , ghci still does not activate
the OverloadedStrings extension when loading the file.
I hadn't noticed that.
I’d consider this a bug until the developers explain why this should or
cannot be different, and suggest you file it as such.
I agree. I've lodged a bug report here:
http://hackage.haskell.org/trac/ghc/ticket/5673
I think it's very dangerous if language extensions leak from modules
by default. For example if someone creates a library and needs to use
some unsafe language extensions like:
{-# LANGUAGE UndecidableInstances, OverlappingInstances, IncoherentInstances #-}
module SomeLib where ...
You surely don't want to silently enable these in some unsuspecting client:
module MyFirstHaskellModule where
import SomeLib
...
I can imagine having a pragma for explicitly exporting language extensions:
{-# EXPORT_LANGUAGE OverloadedStrings #-}
Cheers,
Bas
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[Haskell-cafe] Weird interaction between literate haskell, ghci and OverloadedStrings
Hi,
I'm working on a literate haskell document (actually TeX, but the
example below is just test) and I'm using ByteStrings in the code.
I know I can do:
ghci -XOverloadedStrings file.lhs
or, after ghci is running I can do:
Main :set -XOverloadedStrings
but I'd like to embed a directive in the file so that when loaded
in GHCi, I will automatically get OverloadedStrings. This is mainly
so that it JustWorks(tm) when I pass the file on to someone else.
Is there a way to do this?
There is a short example file below. I'm using ghc-7.0.4 from Debian
testing.
Cheers,
Erik
--8--8--8--8--
{-# LANGUAGE OverloadedStrings #-}
This is just text that that ghc/ghci should ignore
import Data.ByteString (ByteString)
import qualified Data.ByteString.Char8 as BS
Simple function:
newlineCount :: ByteString - Int
newlineCount bs = BS.foldl foldFun 0 bs
where foldFun s ch = if ch == '\n' then s + 1 else s
Once this file is loaded, I should be able to do this:
newlineCount abcd\ncdead\nasdasd\n
--8--8--8--8--
--
--
Erik de Castro Lopo
http://www.mega-nerd.com/
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Re: [Haskell-cafe] Weird interaction between literate haskell, ghci and OverloadedStrings
On 3 December 2011 16:18, Erik de Castro Lopo mle...@mega-nerd.com wrote: Hi, I'm working on a literate haskell document (actually TeX, but the example below is just test) and I'm using ByteStrings in the code. I know I can do: ghci -XOverloadedStrings file.lhs or, after ghci is running I can do: Main :set -XOverloadedStrings Add :set -XOverloadedStrings to a (possibly local) .ghci file? It doesn't contain it within the same document, but then if it's a local one you could also add :load file.lhs in there so that you just have to type ghci. -- Ivan Lazar Miljenovic ivan.miljeno...@gmail.com IvanMiljenovic.wordpress.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Weird interaction between literate haskell, ghci and OverloadedStrings
Ivan Lazar Miljenovic wrote: Add :set -XOverloadedStrings to a (possibly local) .ghci file? It doesn't contain it within the same document, but then if it's a local one you could also add :load file.lhs in there so that you just have to type ghci. Unfortunately, thats no better than telling people do: ghci -XOverloadedStrings file.lhs Probably worse actually. Erik -- -- Erik de Castro Lopo http://www.mega-nerd.com/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
