[Haskell-cafe] Re: Windows details
Andrew Coppin andrewcoppin at btinternet.com writes: Jeff Zaroyko wrote: Andrew Coppin andrewcoppin at btinternet.com writes: Jeff Zaroyko wrote: In theory, you should be able to use mingw's windres tool to produce an object file from the resource definition which you'd link with the rest of your program. I literally cannot *believe* how hard it is to put a few little words into that version tab... Every other kind of resource seems to be completely trivial, but this just won't work for toffee! I'm sure you'll work something out, my test worked, I used a .res file I had lying around from Wine's ddraw.dll, used windres ddraw.res -o version.o to make an object file then using ghc hello.hs version.o linked it against hello world. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Windows console
2008/9/12 Andrew Coppin [EMAIL PROTECTED]: Any ideas about the build log error that's preventing Hackage from autogenerating the documentation? That is a Cabal problem: Duncan Coutts tells me that it is fixed in HEAD, so documentation will be available on Hackage when they update the version of Cabal they are using. Cheers, Max ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Windows console
2008/9/13 Brandon S. Allbery KF8NH [EMAIL PROTECTED]: Right. Unless you send an ^[^H]0;foo^G sequence (^[ being ESC) to your xterm. You'll find that the title changes to foo. 0 = both title and icon 1 = icon name 2 = titlebar text Most X11 terminal emulators use the same protocol. (ISTR that dtterm doesn't, but I don't think most people care any more.) One other gotcha is that Terminal.app on Leopard (dunno about Tiger) treats 0, 1, 2 the same way so if you set the icon name after the title you end up with the icon name in the titlebar. (OSX uses the titlebar text as the icon name when minimized.) Interesting information. I'll look into adding this to my package then: cheers! Max ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Windows console
2008/9/13 Max Bolingbroke [EMAIL PROTECTED]: Interesting information. I'll look into adding this to my package then: cheers! Just FYI, I have now implemented and tested this feature. The new version, 0.5.0, is available on Hackage. Cheers, Max ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Windows console
Max Bolingbroke wrote: 2008/9/13 Max Bolingbroke [EMAIL PROTECTED]: Interesting information. I'll look into adding this to my package then: cheers! Just FYI, I have now implemented and tested this feature. The new version, 0.5.0, is available on Hackage. For both platforms? Out of interest, how do you get the correct package built on each platform? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Erroneous package listings in hackage?
On Sat, Sep 13, 2008 at 1:51 AM, Duncan Coutts [EMAIL PROTECTED] wrote: Perhaps for packages that are installed but not re-installable via Cabal (like cairo, base, ghc etc) it should say something. Do you have any specific suggestions? Well that explains it then! I had no idea it listed stuff not available from Hackage. I've been using `cabal list | grep foo` to search for packages but that's obviously not optimal, it seems. I don't know what would clarify the matter. An available from Hackage: (yes/no) field? Or a flag to pass to `cabal list` to show Hackage stuff only? D -- Dougal Stanton [EMAIL PROTECTED] // http://www.dougalstanton.net ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Windows console
2008/9/13 Andrew Coppin [EMAIL PROTECTED]: Just FYI, I have now implemented and tested this feature. The new version, 0.5.0, is available on Hackage. For both platforms? Of course! My package promises to work cross-platform, after all. Out of interest, how do you get the correct package built on each platform? If you mean how do I compile the ANSI emulator on Windows but the actual ANSI stuff on Unix, most of the magic is in the .cabal file: http://github.com/batterseapower/ansi-terminal/tree/master/ansi-terminal.cabal. I simply turn on the C-preprocessor (CPP) and then supply -DWINDOWS on Windows and -DUNIX on anything else. The actual use of CPP in my source is then confined to a single module (http://github.com/batterseapower/ansi-terminal/tree/master/System/Console/ANSI.hs) which either imports System.Console.ANSI.Windows or System.Console.ANSI.Unix depending on which of those two have been defined. Nothing to it, really. However, this is the stuff that is making the Hackage documentation generation choke currently because until recently Cabal forgot to supply the CPP flags to a Haddock 2 (but not Haddock 0.x) run. All the best, Max ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Windows console
Max Bolingbroke wrote: 2008/9/13 Andrew Coppin [EMAIL PROTECTED]: Just FYI, I have now implemented and tested this feature. The new version, 0.5.0, is available on Hackage. For both platforms? Of course! My package promises to work cross-platform, after all. [rejoyce!] Out of interest, how do you get the correct package built on each platform? If you mean how do I compile the ANSI emulator on Windows but the actual ANSI stuff on Unix, most of the magic is in the .cabal file: I simply turn on the C-preprocessor (CPP) and then supply -DWINDOWS on Windows and -DUNIX on anything else. The actual use of CPP in my source is then confined to a single module which either imports System.Console.ANSI.Windows or System.Console.ANSI.Unix depending on which of those two have been defined. Nothing to it, really. However, this is the stuff that is making the Hackage documentation generation choke currently because until recently Cabal forgot to supply the CPP flags to a Haddock 2 (but not Haddock 0.x) run. Hmm, I wasn't aware you could use the C preprocessor on Haskell source code. That could be rather useful, e.g., for adding or removing debug code. Anyway, that still leaves one question: how do you figure out which platform you're on so you can set the right options? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Windows console
On Sat, 2008-09-13 at 13:41 +0100, Andrew Coppin wrote: If you mean how do I compile the ANSI emulator on Windows but the actual ANSI stuff on Unix, most of the magic is in the .cabal file: I simply turn on the C-preprocessor (CPP) and then supply -DWINDOWS on Windows and -DUNIX on anything else. Anyway, that still leaves one question: how do you figure out which platform you're on so you can set the right options? As Max suggested, look in the .cabal file. You'll find this snippet: if os(windows) Build-Depends: Win32 = 2.0 Cpp-Options:-DWINDOWS [... other stuff ...] else -- We assume any non-Windows platform is Unix Build-Depends: unix = 2.3.0.0 Cpp-Options:-DUNIX [... other stuff ...] Extensions: CPP Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Erroneous package listings in hackage?
On Sat, 2008-09-13 at 12:06 +0100, Dougal Stanton wrote: On Sat, Sep 13, 2008 at 1:51 AM, Duncan Coutts [EMAIL PROTECTED] wrote: Perhaps for packages that are installed but not re-installable via Cabal (like cairo, base, ghc etc) it should say something. Do you have any specific suggestions? Well that explains it then! I had no idea it listed stuff not available from Hackage. I've been using `cabal list | grep foo` to search for packages but that's obviously not optimal, it seems. I guess you're searching through the package description too. The reason cabal list currently only searches though the name (though it does do substring matching) is that parsing every .cabal file in the index is rather slow. At some point we'll probably have to make a cache of the info which we generate when the index is downloaded. I don't know what would clarify the matter. An available from Hackage: (yes/no) field? Or a flag to pass to `cabal list` to show Hackage stuff only? We've got an --installed flag to list only installed stuff, we could add one for the opposite case. You can file a feature request ticket here: http://hackage.haskell.org/trac/hackage/ Or send us a patch! :-) I don't expect it'd be hard to add. Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Windows details
Jeff Zaroyko wrote: Andrew Coppin andrewcoppin at btinternet.com writes: I literally cannot *believe* how hard it is to put a few little words into that version tab... Every other kind of resource seems to be completely trivial, but this just won't work for toffee! I'm sure you'll work something out, my test worked, I used a .res file I had lying around from Wine's ddraw.dll, used windres ddraw.res -o version.o to make an object file then using ghc hello.hs version.o linked it against hello world. Well, you must either be running under a different OS or have Cygwin installed, because when I try it, it just complains constantly. (Can't find gcc, can't find cc1, can't find crt.o, and so forth.) At this point, I'm giving up. I only wanted this for the shininess value. It's not worth this much trouble... ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re[2]: [Haskell-cafe] Re: Windows details
Hello Andrew, Saturday, September 13, 2008, 5:13:21 PM, you wrote: Well, you must either be running under a different OS or have Cygwin installed, because when I try it, it just complains constantly. (Can't find gcc, can't find cc1, can't find crt.o, and so forth.) At this point, I'm giving up. I only wanted this for the shininess value. It's not worth this much trouble... yes, you should add path to gcc to your path. that's what i have in my makefile - hope it can help: GHCDIR = C:\Base\Compiler\ghc LIBDIR = $(GHCDIR)\gcc-lib INCDIR = $(GHCDIR)\include\mingw GCC = $(GHCDIR)\gcc.exe -B$(LIBDIR) -I$(INCDIR) -- Best regards, Bulatmailto:[EMAIL PROTECTED] ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] nooby question on typing
Hi,
I have a question about types in Haskell. I feel that I am overlooking some
obvious solution, but I do not manage to get it right. Here is the plot:
I have got 4 different types of 'rules', each with it's own constructor. So
i defined:
type Rules = [Rule]
data Rule = RuRule
| SgRule
| GcRule
| FrRule
deriving (Eq,Show)
data RuRule
= Ru { rrsrt :: Char
, rrant :: Expression
, rrfps :: FilePos
} deriving (Eq,Show)
data SgRule
= Sg { srfps :: FilePos
, srsig :: Rule
, srxpl :: String
, srtyp :: (Concept,Concept)
} deriving (Eq,Show)
data GcRule
= Gc { grfps :: FilePos
, grspe :: Morphism
, grgen :: Expression
} deriving (Eq,Show)
data FrRule
= Fr { fraut :: AutType
, frdec :: Declaration
, frcmp :: Expression
, frpat :: String
} deriving (Eq,Show)
Now I would like to be able to use these rules without knowing what kind
they are, in lists, however i get errors like
Couldn't match expected type `Rule' against inferred type `SgRule'.
Is there any other (even trivial?) way to get this done? I know Haskell well
enough to know that it is possible, but I don not know Haskell well enough
to know how to do it :teeth:
Any help is kindly appreciated!
Han Joosten
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Re: [Haskell-cafe] nooby question on typing
On Sat, Sep 13, 2008 at 2:49 PM, Han Joosten [EMAIL PROTECTED]wrote: Hi, I have a question about types in Haskell. I feel that I am overlooking some obvious solution, but I do not manage to get it right. Here is the plot: I have got 4 different types of 'rules', each with it's own constructor. So i defined: type Rules = [Rule] data Rule = RuRule | SgRule | GcRule | FrRule deriving (Eq,Show) This effectively creates an enum type. I.e. each case here doesn't contain any data other than the tag. I think you're getting confused because the constructor is named the same as the type you're expecting to store. Try something like: type Rules = [Rule] data Rule = RuRule | MkSgRule SgRule | MkGcRule GcRule | MkFrRule FrRule deriving (Eq,Show) So MkSgRule is a tag or a label deciding which version of Rule you're building, and it also has a value of type SgRule. Now you can create a list or Rule like so: mylist :: [Rule] mylist = [ MkSgRule mysgrule, MkGcRule mygcrule ] where mysgrule :: SgRule and mygcrule :: GcRule. -- Sebastian Sylvan +44(0)7857-300802 UIN: 44640862 ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Hackage needs a theme song!
On 2008.09.12 20:35:32 -0700, Jason Dagit [EMAIL PROTECTED] scribbled 1.7K characters: I realized tonight that Hackage needs a theme song. Here is my attempt at it, apologies to Jefferson Starship: We built this hackage, We built this hackage on lambda and types ... Pretty good. Any plans to stick it in http://haskell.org/haskellwiki/Humor? -- gwern SUSLO Freespire INFOSEC M-x Templar Uzbekistan FID Tokyo NTT infowar signature.asc Description: Digital signature ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Fwd: Computer Language Benchmarks Game: [Which parallel problem would you add and why?]
The Computer Language Benchmarks Game has a quad core (as you probably know). But they're looking for new benchmarks. Ones that can actually exploit parallelism. If you've got suggestions on good parallelism benchmarks, and why they're good, add them to the alioth or reddit threads. - Forwarded message from Isaac Gouy - Which parallel problem would you add and why? http://alioth.debian.org/forum/forum.php?thread_id=14502forum_id=2840 Ask Proggit: Which parallel problem would you add now The Computer Language Benchmarks Game is measured on quad-core hardware, and why? http://www.reddit.com/r/programming/comments/718qf/ask_proggit_which_parallel_problem_would_you_add/ - End forwarded message - ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] ANNOUNCE: citeproc-hs, a Haskell implementation of the Citation Style Language designed for Pandoc
Hello, I'm happy to announce the first release of citeproc-hs, a Haskell implementation of the Citation Style Language. citeproc-hs adds to Pandoc, the famous Haskell text processing tool, a Bibtex like citation and bibliographic formatting and generation facility. ABOUT The Citation Style Language (CSL) is an XML language for specifying citation and bibliographic formatting, similar in principle to BibTeX .bst files or the binary style files in commercial products like Endnote or Reference Manager. CSL is used by Zotero for bibliographic style formatting, and a huge number of CSL styles have been developed by the Zotero community. There are plans to use CSL in the future release of OpenOffice: http://bibliographic.openoffice.org/ citeproc-hs is a library that exports functions to parse CSL styles and MODS collections, to process lists of citation groups and to format the processed output. The output is a Haskell data type that can be further processed for conversion to any kind of formats (at the present time plain ASCII and the Pandoc native format) citeproc-hs was developed in order to add to Pandoc Bibtex like citations and automatic reference and bibliography generation. More information, with installation instructions, can be found here: http://code.haskell.org/citeproc-hs/ DOWNLOADS citeproc-hs can be downloaded from Hackage: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/citeproc-hs To get the darcs source run: darcs get http://code.haskell.org/citeproc-hs/ KNOWN ISSUES citeproc-hs is in an early stage of development and the CSL is not complete yet. Specifically, citation collapsing is not implemented, and some formatting options are not working neither. The MODS parser needs some refinement too. BUG REPORTS To submit bug reports you can you the Google code bug tracking system available at the following address: http://code.google.com/p/citeproc-hs/issues CREDITS Bruce D'Arcus, the author of CSL, has been very kind and patient with me when I was trying to understand the CSL schema, and provided me with ideas, comments and suggestions that made it possible to come to something usable. John MacFarlane, the author of Pandoc, has been very supportive of the project and provided a lot of useful feed back, comments and suggestions. Hope you'll enjoy, Andrea Rossato ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Hackage checks
Hi, the Hackage upload script performs some checks on the packages being uploaded. In my case, a library, I need to use the cabal generated Paths_package file to access some locale data stored in a data file directory. This requires to include in hs-source-dirs dist/build/autogen, which doesn't exist in the source tree, since it's generated by cabal in the build process (the inclusion is made necessary by a bug in Cabal-1.2 which doesn't automatically search dist/build/autogen, see [1]). And so Hackage complains: I needed to manually include such an empty directory in the source code archive. Any way out? TIA Andrea [1] http://www.haskell.org/pipermail/libraries/2008-July/010078.html ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] nooby question on typing
So it sounds like what you want to do is this:
rulesList =
[ Ru 'a' someExpr someFilePos
, Sg someFilePos (Gc someOtherFilePos someMorphism someExpr) hello (a,b)
]
(This won't compile because Ru and Sg construct different types.)
You have a few options to do this:
1) Move the constructors into the Rule type. This means you don't
get functions that only apply to RuRule, or any of the other types
without them being partial and subject to runtime error, so this may
not be safe enough for you. But it is the simplest answer.
data Rule = Ru { rrst :: Char, other stuff... } | Sg { ... } | ...
2) Smart constructors!
data Rule = MkRu RuRule | MkSg SgRule | ...
ru a b c = MkRu (Ru a b c)
...
Now just use the lowercase ru instead of Ru to construct a Rule
(instead of the specific rule type).
rulesList =
[ ru 'a' someExpr someFilePos
, sg someFilePos (Gc someOtherFilePos someMorphism someExpr) hello (a,b)
]
This will work! You will still need the MkRu (Ru a b c) if you
pattern match on Rule, though.
3) dynamic typing and/or existential types, with smart constructors
{-# LANGUAGE ExistentialQuantification, DeriveDataTypeable, PatternGuards #-}
import Data.Typeable
data RuRule = Ru { ... } deriving (Eq, Show, Typeable)
...
class Typeable a = IsRule a
instance IsRule RuRule
instance IsRule GcRule
...
data Rule = forall a. IsRule a = Rule a
ru a b c = Rule (Ru a b c)
unRu :: Rule - Maybe RuRule
unRu (Rule x) = cast x
...
-- example of pattern matching using pattern guards as views
test :: Rule - Bool
test x
| Just (Ru _ _ _) - unRu x = True
| Just (Sg _ x2 _ _) - unSg x,
Just (Ru a _ _) - unRu x2 = a == 'h'
| otherwise = False
Hopefully one of these will suit your needs!
-- ryan
On Sat, Sep 13, 2008 at 6:49 AM, Han Joosten [EMAIL PROTECTED] wrote:
Hi,
I have a question about types in Haskell. I feel that I am overlooking some
obvious solution, but I do not manage to get it right. Here is the plot:
I have got 4 different types of 'rules', each with it's own constructor. So
i defined:
type Rules = [Rule]
data Rule = RuRule
| SgRule
| GcRule
| FrRule
deriving (Eq,Show)
data RuRule
= Ru { rrsrt :: Char
, rrant :: Expression
, rrfps :: FilePos
} deriving (Eq,Show)
data SgRule
= Sg { srfps :: FilePos
, srsig :: Rule
, srxpl :: String
, srtyp :: (Concept,Concept)
} deriving (Eq,Show)
data GcRule
= Gc { grfps :: FilePos
, grspe :: Morphism
, grgen :: Expression
} deriving (Eq,Show)
data FrRule
= Fr { fraut :: AutType
, frdec :: Declaration
, frcmp :: Expression
, frpat :: String
} deriving (Eq,Show)
Now I would like to be able to use these rules without knowing what kind
they are, in lists, however i get errors like
Couldn't match expected type `Rule' against inferred type `SgRule'.
Is there any other (even trivial?) way to get this done? I know Haskell well
enough to know that it is possible, but I don not know Haskell well enough
to know how to do it :teeth:
Any help is kindly appreciated!
Han Joosten
--
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http://www.nabble.com/nooby-question-on-typing-tp19470727p19470727.html
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[Haskell-cafe] Views
Hello! List-like data structures should IMHO provide safe versions of 'head' and 'tail' (with safe I mean 'not partial', i. e. functions that don't provoke an 'error' when called with an empty collection). As far as I know, this is usually called 'view' and and has a type signature like view :: SomeDataStructure a - View a with data View = Empty | Cons a (SomeDataStructure a) A good example for this is Data.Sequence. My question is: Why is this not expressed in terms of Maybe? view :: SomeDataStructure a - Maybe (a, SomeDataStructure a) This would be easier to use, as there's no need for a new View type and because Maybe already provides instance declarations for a lot of useful classes (Functor, Monad, etc.) and handy helper functions (e. g. 'maybe'). Then you could, for instance, say: head xs = maybe undefined fst (view xs) tail xs = maybe undefined snd (view xs) You can of course argue that you want viewl and viewr to have different types in the case of Data.Sequence, but this is not the case for other, rather one-ended, data types, is it? Long story short, my problem is the following: I want to provide a 'view' function for Data.Heap in my heap [1] package and I don't know whether... a) ... to use Maybe b) ... to provide my own Data.Heap.View type c) ... a Data.View package with a View type should be included in the containers- or even base-package. This would prevent lots of small projects from creating totally equivalent View types. Maybe there even exists a Data.View package that I didn't find? Regards, Stephan [1] http://hackage.haskell.org/cgi-bin/hackage-scripts/package/heap-0.3.1 -- Früher hieß es ja: Ich denke, also bin ich. Heute weiß man: Es geht auch so. - Dieter Nuhr ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Views
a) ... to use Maybe b) ... to provide my own Data.Heap.View type leave the choice up to the programmer, and provide a generic interface, accepting any MonadZero (*) instance. cf. Data.Set.maxView http://www.haskell.org/hoogle/?hoogle=maxView (*) ah - I forgot, MonadZero didn't quite make it, instead we have fail in Monad, and mzero in MonadPlus. Sure there must have been a reason for this... signature.asc Description: OpenPGP digital signature ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Views
On Sat, Sep 13, 2008 at 11:19 AM, Stephan Friedrichs [EMAIL PROTECTED] wrote: data View = Empty | Cons a (SomeDataStructure a) A good example for this is Data.Sequence. My question is: Why is this not expressed in terms of Maybe? view :: SomeDataStructure a - Maybe (a, SomeDataStructure a) I think the usual reason this is done is because it is clearer to read. Since Maybe is so generally useful, when you read code that uses it, you have to figure out what use it is being put towards. What does Nothing mean? What does Just (a,b) mean? are the kinds of questions that go through your head, and they distract you from the problem at hand. On the other hand, reading code that uses the View type, it is immediately clear what Empty and Cons mean. But you're right, Maybe has a lot of useful helper functions and instances. -- ryan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Hackage checks
On Sat, 2008-09-13 at 20:36 +0200, Andrea Rossato wrote: Hi, the Hackage upload script performs some checks on the packages being uploaded. In my case, a library, I need to use the cabal generated Paths_package file to access some locale data stored in a data file directory. This requires to include in hs-source-dirs dist/build/autogen, which doesn't exist in the source tree, since it's generated by cabal in the build process (the inclusion is made necessary by a bug in Cabal-1.2 which doesn't automatically search dist/build/autogen, see [1]). Any path in your .cabal file that uses dist/ is wrong. Sorry. The dist path can be changed by the user (--builddir) and its internal layout is not fixed. And so Hackage complains: I needed to manually include such an empty directory in the source code archive. Any way out? I can't think of any other workaround for 1.2 so I think you'll have to require Cabal-1.4 for your package. Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell Weekly News: Issue 85 - September 13, 2008
dmehrtash: I have a newbie question Does theorem proofs have a use for an application? Take for example the IRC bot example ([1]http://www.haskell.org/haskellwiki/Roll_your_own_IRC_bot) listed below. Is there any insight to be gained by theorem proofs (as in COQ) into the app? Some customers require very high level of assurance that there are no bugs in the code you ship to them. Theorem proving is one great way to make those assurances. -- Don P.S. publicity In fact, it's the subject of a talk on Tuesday, http://www.galois.com/blog/2008/09/11/theorem-proving-for-verification/ /publicity ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANN: pandoc 1.0.0.1
On Sat, Sep 13, 2008 at 09:31:50PM -0500, brian wrote: On Sat, Sep 13, 2008 at 8:29 PM, John MacFarlane [EMAIL PROTECTED] wrote: + Code is -Wall clean Thanks, I appreciate it. I wish more people paid attention to this. Well. I often pay attention to it. That doesn't mean I always heed it ;-) Like all -Wall stuff, sometimes warnings are great and sometimes warnings are noise. There are two warnings that I am prone to ignore: 1) No type definition for top-level declarations Whether or not I ignore this depends on what sort of code I'm working on. If I'm using Haskell as, essentially, a script language, or writing a quick and small Parsec parser, adding a bunch of type declarations can serve to make the code less readable and certainly more difficult to update and maintain. That said, for larger projects or computation algorithms, I'd usually add declarations. When I'm leaving off the declarations, my code sometimes winds up looking like something vaguely resembling Python. Sometimes time declarations just get in the way. Cue type inference. One of my favorite things about Haskell: it can be as compact as Python (or moreso), yet detect type errors at compile time. 2) Variable x defined but not used I most often ignore this when it occurs in a function definition. Sometimes I may have a function that could be written foo _ (x, _) _ = bar (x + 5) But for clarity's sake on what all the unused args are, which really helps for future maintainability, I'll usually use a descriptive -- but unused -- variable name. Some of my libraries, on the other hand, are periodically validated against -Wall -Werror. -- John ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell Weekly News: Issue 85 - September 13, 2008
What I am trying to figure out is that say on the code for the IRC bot that is show here http://www.haskell.org/haskellwiki/Roll_your_own_IRC_bot/Source What would theorem proofs do for me? Daryoush On Sat, Sep 13, 2008 at 9:29 PM, Don Stewart [EMAIL PROTECTED] wrote: dmehrtash: I have a newbie question Does theorem proofs have a use for an application? Take for example the IRC bot example ([1]http://www.haskell.org/haskellwiki/Roll_your_own_IRC_bot) listed below. Is there any insight to be gained by theorem proofs (as in COQ) into the app? Some customers require very high level of assurance that there are no bugs in the code you ship to them. Theorem proving is one great way to make those assurances. -- Don P.S. publicity In fact, it's the subject of a talk on Tuesday, http://www.galois.com/blog/2008/09/11/theorem-proving-for-verification/ /publicity ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell Weekly News: Issue 85 - September 13, 2008
What would theorem proofs do for me? Imagine if you used SmallCheck to exhastively test the ENTIRE problem space for a given property. Now imagine you used your brain to show the programs correctness before the heat death of the universe... Proofs are not features, nor are they code. What you prove is entirely up to you and might not be what you think. Take, for example, the issue of proving a sort function works correctly [1]. I'm not saying this to discourage complete proofs, but just cautioning you that proving something as unimportant and IO laden as an IRC bot probably isn't the best example. Do see the linked PDF, and [2] as well. Oh, and for examples where people should have used FM, search for 'ariane 1996' or the gulf war patriot missle failure TomMD [1] http://www.cl.cam.ac.uk/~mjcg/Teaching/SpecVer1/Lectures/pslides07x4.pdf [2] http://users.lava.net/~newsham/formal/reverse/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
