[Haskell-cafe] Internships on GHC and Haskell at MSR Cambridge
Gentle Haskellers Would you be interested in working for three months at Microsoft Research, Cambridge, on a project related to GHC or Haskell? MSR Cambridge now takes interns *year-round*, not just in the summer months. Simon Marlow and I are keen to attract motivated and well-qualified folk to work with us on our research, and on improving or developing GHC. If you or one of your students is interested, you can find more details here http://hackage.haskell.org/trac/ghc/wiki/Internships Our next empty slot is the Oct-Dec period, but you are welcome to apply for some later period. Simon PJ PS: There are lots of other programming-language folk at MSR (F#, security, probabilistic languages...), and stuff beyond that (machine learning, systems and networks...); see http://research.microsoft.com/aboutmsr/labs/cambridge/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Newbie Q: Deriving MyOrd from Eq problem
I am trying to derive MyOrd class from Eq (Prelude): class Eq a = MyOrd a where (%=), (%), (%=) :: a - a - Bool x %= y = (x y || x == y) x % y = y x x %= y = (y x || x == y) I get these errors: ClassTest.hs:28:21: Could not deduce (Ord a) from the context (MyOrd a) arising from use of `' at C:/wks/haskell-wks/ClassTest.hs:28:21 Probable fix: add (Ord a) to the class or instance method `%=' In the first argument of `(||)', namely `x y' In the definition of `%=': %= x y = ((x y) || (x == y)) In the definition for method `%=' ClassTest.hs:29:20: Could not deduce (Ord a) from the context (MyOrd a) arising from use of `' at C:/wks/haskell-wks/ClassTest.hs:29:20 Probable fix: add (Ord a) to the class or instance method `%' In the definition of `%': % x y = y x In the definition for method `%' ClassTest.hs:30:21: Could not deduce (Ord a) from the context (MyOrd a) arising from use of `' at C:/wks/haskell-wks/ClassTest.hs:30:21 Probable fix: add (Ord a) to the class or instance method `%=' In the first argument of `(||)', namely `y x' In the definition of `%=': %= x y = ((y x) || (x == y)) In the definition for method `%=' Failed, modules loaded: none. Q: What's wrong? Why 'Ord' gets into play here? Thanks, Dima ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Newbie Q: Deriving MyOrd from Eq problem
I am trying to derive MyOrd class from Eq (Prelude): class Eq a = MyOrd a where (%=), (%), (%=) :: a - a - Bool x %= y = (x y || x == y) x % y = y x x %= y = (y x || x == y) Q: What's wrong? Why 'Ord' gets into play here? You are using which is a function on types that instance the class Ord, so the compiler is telling you to add (Ord a) to the same place you have (Eq a) or don't use or or any function in the class Ord. You can the prelude and thus the Ord class and make your own and functions but you can't make them refer to the real and functions without Ord because that is where they live. Jared. -- http://www.updike.org/~jared/ reverse )-: ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Newbie Q: Deriving MyOrd from Eq problem
Sorry, left out an important verb, *hide*: You can the prelude and thus the Ord class and make your own and You can *hide* the prelude and thus the Ord class and make your own and Jared. -- http://www.updike.org/~jared/ reverse )-: ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Newbie Q: Deriving MyOrd from Eq problem
Hello Dmitri, Tuesday, July 25, 2006, 8:15:41 PM, you wrote: class Eq a = MyOrd a where (%=), (%), (%=) :: a - a - Bool x %= y = (x y || x == y) x % y = y x x %= y = (y x || x == y) you are mixing definition of class and its (default) instance. try the following: class Eq a = MyOrd a where (%=), (%), (%=) :: a - a - Bool instance Ord a = MyOrd a where x %= y = (x y || x == y) x % y = y x x %= y = (y x || x == y) although i don't think it is what you want. actually Haskell don't have a good way to define default instance for some subclass, although there are some proposals how this can be addressed. you should either define exactly one instance for all Orded types or duplicate this trivial definition in every instance. in GHC you also has an option to use overlapping instances but this can work only if all your other instance definitions don't use deriving from typeclasses. i.e. the following is prohibited: class Eq a = MyOrd a where ... instance Ord a = MyOrd a where ... instance SomeClass a = MyOrd a where ... and even if you will be accurate, i'm not sure that overlapping will work properly ps: you can ask me in Russian via private mail -- Best regards, Bulatmailto:[EMAIL PROTECTED] ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] ghc hackathon start time?
What time on September 14th will the GHC Hackathon begin? I don't need a precise answer, just a quick one. Plus or minus an hour will do.Thanks,Greg ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
RE: [Haskell-cafe] Newbie Q: Deriving MyOrd from Eq problem
Bulat, Dmitri is not necessarily mixing [...] class and its (default) instance. Bulat, one could suspect a reasonable use of default class methods: http://www.haskell.org/onlinereport/decls.html#overloading Indeed, Dmitri's declarations make sense as default class methods. ... except for Jared's observation: the attempt to rely on Ord. If % in place of was used on the RHSs, then this would really look like default methods. Ralf PS: We don't want to send people using overlapping instances more often than necessary :-) -Original Message- From: [EMAIL PROTECTED] [mailto:haskell-cafe- [EMAIL PROTECTED] On Behalf Of Bulat Ziganshin Sent: Tuesday, July 25, 2006 9:46 AM To: Dmitri O.Kondratiev Cc: haskell-cafe@haskell.org Subject: Re: [Haskell-cafe] Newbie Q: Deriving MyOrd from Eq problem Hello Dmitri, Tuesday, July 25, 2006, 8:15:41 PM, you wrote: class Eq a = MyOrd a where (%=), (%), (%=) :: a - a - Bool x %= y = (x y || x == y) x % y = y x x %= y = (y x || x == y) you are mixing definition of class and its (default) instance. try the following: class Eq a = MyOrd a where (%=), (%), (%=) :: a - a - Bool instance Ord a = MyOrd a where x %= y = (x y || x == y) x % y = y x x %= y = (y x || x == y) although i don't think it is what you want. actually Haskell don't have a good way to define default instance for some subclass, although there are some proposals how this can be addressed. you should either define exactly one instance for all Orded types or duplicate this trivial definition in every instance. in GHC you also has an option to use overlapping instances but this can work only if all your other instance definitions don't use deriving from typeclasses. i.e. the following is prohibited: class Eq a = MyOrd a where ... instance Ord a = MyOrd a where ... instance SomeClass a = MyOrd a where ... and even if you will be accurate, i'm not sure that overlapping will work properly ps: you can ask me in Russian via private mail -- Best regards, Bulatmailto:[EMAIL PROTECTED] ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ghc hackathon start time?
What time on September 14th will the GHC Hackathon begin? I don't need a precise answer, just a quick one. Plus or minus an hour will do. Morning certainly. In the absence of a more definite answer from the Simons (or the Galois hosts), I would guess 0900-1000hrs local time. Regards, Malcolm ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re[2]: [Haskell-cafe] Newbie Q: Deriving MyOrd from Eq problem
Hello Ralf, Tuesday, July 25, 2006, 9:59:58 PM, you wrote: Dmitri is not necessarily mixing [...] class and its (default) instance. sorry, i was thoughtless. it really seems like a mistake in use MyOrd class instead of attempt to use Ord operations. Dmitri should know better :) -- Best regards, Bulatmailto:[EMAIL PROTECTED] ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] scripting in haskell
Hi, I was playing around with runhaskell (runghc to be precise), and I discovered the limitation wherein you have to use the file suffix .hs. Don't get me wrong, runhaskell is great, but if you didn't have that restriction it would make haskell much more attractive to many programmers who write standalone scripts. Of course it's always possible to do e.g. (file: hello) #! /bin/sh runhaskell Hello.hs (file: Hello.hs) module Main where main :: IO () main = putStrLn hello, world! but that's pretty inconvenient. What I'd like is: (file: hello) #! /usr/bin/env runhaskell module Main where main :: IO () main = putStrLn hello, world! which is _almost_ doable; you have to name the file hello.hs. What would really be optimal is something like (file: hello) #! /usr/bin/env runhaskell -fglasgow-exts -- extra arguments to runhaskell !# module Main where main :: IO () main = putStrLn hello, world! Looking through the mailing list I see something from May 2005 on this topic about adding the equivalent of gcc's -x option to ghc. What's the status of that? Cheers, Mike ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Why Haskell?
Well now that I understand how it works, I'm perfectly happy with the current functionality. As long as I put all my FFI imports into one module and compile that, then I can load the other modules into GHCi at will during development and testing. I was going to do some FFI imports into another module but will forgo that. I did run into an amusing problem where my matrices were not being updated after a :reload operation (or was it a :load?) and a re-evalution of main in GHCi. I view the matrices as constant globals, and therefore do an unsafePerformIO to get their indices. Another evaluation of main left the indices unchanged pointing to the old matrices. At least that what appears to have happen. I should probably take a closer look when I have a second. Simon Peyton-Jones wrote: | I think I understand my issue now with this (other than the anomaly of | the above example). I've been using the make option with ghc to compile | all the dependent sources, creating binaries for all of them. Those | binaries can be loaded into GHCi, but if you do so it will not make the | imports available to you for use. Thus my main.hs has the header | import Matrix | import Parsefile | import Array | import NetPrams | import System.IO.Unsafe | | . | | If main.hs has not been brought up to date, I can load main.hs into the | interpreter and the functions defined in Matrix for example will be in | scope and usable. If on the other hand I've just run ghc on main, I can | load main.hs in, but the functions in Matrix will not be available. | Perhaps the solution is to create a script file that loads all the | modules in and adds them to the current scope. The GHC user manual discusses this point: http://www.haskell.org/ghc/docs/latest/html/users_guide/ch03s04.html#ghc i-scope When you *compile* a module, GHC does a whole lot of inlining, and functions that are exported may not even exist any more. That's why you can't necessarily see the full top-level scope of a compiled module (the :m *M form described in the manual). If you *interpret* a module, GHC is careful never to discard any top-level definition, so that you can see the full top-level scope, just as you wrote it. Maybe there should be a way to tell GHC to retain top level defns even when compiling; but currently the story is that you must interpret the .hs files if you want to see the top level defns. Simon ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Why Haskell?
vim has been my choice as well. Now that vim 7.0 has tabbed windows it's better than ever. All they need now is a way to integrate it with a console window I guess you can find scite/scintilla settings for Haskell as well http://www4.in.tum.de/~haftmann/resources/haskell.properties Marc Weber wrote: 2) Recompiling binaries (necessary in order to link in foreign object code into GHCi) is slow using GHC. Moreover I have to restart GHCi if I want to reload a changed DLL (unless there is a way to unload a DLL in GHCi). It also requires jumping around between several console windows to get the job done. (I'm not using an IDE does one exist?) There are several. (I know of one using visual studio and eclipsefp).. It should|nt be a problem to find them.. But I still prefer vim :) Concerning switching between several console windows... Perhaps try something like mrxvt which has several tabs to run more than one shell. You can then use key combinations to switch.. (I haven't used mrxvt on cygwin yet but I've read that it runs there) Marc ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] scripting in haskell
Looking through the mailing list I see something from May 2005 on this topic about adding the equivalent of gcc's -x option to ghc. What's the status of that? You should always be able to do something like this: #!/usr/bin/runfileAsHSFile $@ module Main where import blah runfileAsHSFile #!/bin/sh # run a file by creating a virtual hs file (fifo file pipe) fileToRun=$1; shift; f=tempfile -s .hs mkfifo $f sed -e '1d' $fileToRun $f # remove the first shabeng line using sed.. runhaskell $f rm $f This is written from scratch but should work without much changes.. But there might be much better solutions. Marc Weber ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] RE: ANN: System.FilePath 0.9
[Sorry for the late reply.] On Wed, Jul 19, 2006 at 03:16:48AM +0100, Neil Mitchell wrote: I want to make sure a filename is valid. For example, prn and con This is another rat's nest, so I suggest that it be dealt with separately from the basic filepath module. The notion of valid is squishy: It depends entirely on what you intend to do with the path. Its a rats nest to do it properly, but some very basic idea of does this path have things which there is no way could possibly be in a file - for example c:\|file is a useful thing to have. This seems to encourage the classic mistake of checking not known bad rather than known good. known bad is rarely useful in my experience. What use case do you have in mind? In this library proposal, there are a bunch of xxxDrive functions that many Unix-oriented programmers are sure to ignore because they are no-ops on Unixy systems. Even on Windows, they are not very useful: I strongly agree about this. The temptation in path modules seems to be to throw in everything you can think of (without specifying any of it precisely), just in case someone finds it useful. The drive functions stand on their own as a chunk, and are possibly not well suited to a Posix system, but are critical for a Windows system. Why are they critical for portable code? I am fine with Windows-specific functions, but I think it's a mistake to bundle them portable functions. (In my design, I have separate types for Windows and Unix paths, and imagine full support for Windows-specific operations, but only on the Windows type.) I have tried to specify the functions precisely, and I use this specification as a test suite. Currently there are 114 properties in this test suite, all can be seen on the haddock documentation. If you consider any function to be ambiguously specified, please say which one and I'll add extra tests until it gives you no suprises at all. My criticism is that your properties are all specified in terms of string manipulation. The whole point of paths is that they are interpreted by the system, so if you neglect to say what your operations mean to the system, what have you specified? Here are some specific cases I take issue with. (Quotes are from your generated docs.) Sorry if I seem to be piling it on, but I think these matters are important for a good path library. pathSeparator :: Char The character that seperates directories. So what do I do with this? If I need it, it seems like the module has failed. splitFileName :: FilePath - (String, String) Split a filename into directory and file. Which directory and which file? splitFileName bob == (, bob) is not a directory. Windows: splitFileName c: == (c:,) c: is arguably not a directory. (Consider that dir c: lists the current directory on c:, not c:\) getFileName test/ == is not a filename. Also, it looks from this that you treat paths differently depending on whether they end in a separator. Yet this makes no difference to the system. That seems wrong to me. setFileName :: FilePath - String - FilePath Set the filename. This is vague to me. Eg, what does it do with /, which has no filename? getDirectory :: FilePath - FilePath Get the directory name, move up one level. What does this mean, in the presence of dots and symlinks? normalise :: FilePath - FilePath Normalise a file As Simon asked, when is this safe to use? equalFilePath :: FilePath - FilePath - Bool Equality of two FilePaths. If you call fullPath first this has a much better chance of working. Note that this doesn't follow symlinks or DOSNAM~1s. As you acknowledge, it's a crap-shoot. So what's the point? isValid :: FilePath - Bool Is a FilePath valid, i.e. could you create a file like it? There are a whole host of reasons you might not be able to create a file. Which ones does this address? I tried to export a minimal set of operations that seem to me sufficient for everything not very platform-specific (though I am interested in counterexamples): Anything to do with file extensions? Its also important (I feel) for people to have easy access to common operations, but I guess that is a design decision. I think of that as a separate module, because extensions have no meaning to the system and can be done with portable, functional code, as far as I understand. Andrew ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] StablePtr's and castStablePtrToPtr
I have a query which is asked out of interest's sake...
I'm essentially looking for an affirmation of what I think I already
understand (or some info if I'm deluded ;)).
To put this in context...
I have some C code...
typedef int func(void *);
void from_maybe_int(void *val, func *my_func)
{
int i;
i = my_func(val);
printf(value within C: %d\n, i);
}
And some Haskell code...
type FromMaybeInt = StablePtr (Maybe Int) - IO CInt
foreign import ccall wrapper
wrapFromMaybeInt :: FromMaybeInt
- IO (FunPtr FromMaybeInt)
foreign import ccall from_maybe_int
cFromMaybeInt :: StablePtr (Maybe Int)
- FunPtr GetJust
- IO ()
functionToPass :: FromMaybeInt
functionToPass sPtr = do
m - deRefStablePtr sPtr
case m of
Nothing - return (-1)
Just i - return (fromIntegral i)
main :: IO ()
main = do sPtr - newStablePtr (Just 3) -- for example
funPtr - wrapFromMaybeInt functionToPass
cFromMaybeInt sPtr funPtr
freeStablePtr sPtr
The compiled program works fine. However I wanted to check this was
correct usage. As in, is perfectly fine to pass a value of type
StablePtr a into C?
Am I correct in thinking that StablePtr is defined as a void pointer in
C? From my very limited understanding of C, it is also the case that you
can implicitly cast a void pointer to any other pointer type and
vice-versa. Some appear to deem it bad practice if you explictly give
the cast.
So therefore I am somewhat hazy on the use for castStablePtrToPtr. I
found the ghc docs to be quite cryptic for this function.
Google dug up a few examples of it's use in PUGS... which has lead me to
think that the function is purely for type 'convience' in Haskell. Is
this the case or am I missing a use case here?
Disclaimer: My knowledge and experience of C is somewhat limited.
Ironically I have started playing with C by way of Haskell. (Sick and
twisted I know).
Thanks, Daniel James
P.S. I must say, I really like the Haskell FFI. Very clean and
enjoyable to work with.
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: ANN: System.FilePath 0.9
Hi
It's already there - see System.Directory.createDirectoryIfMIssing.
I'd missed that one entirely, and I think other people had (because I
added ensureDirectory at a request of several people), will go.
If we have shortPath at all, perhaps it would be better named
relativeToCurrentDIrectory?
Make sense, shortPath is not particularly well defined by name.
I'm not sure about canonicalPath. This interface seems to suffer from the same
race conditions as the temporary file interface: the answer is immediately
invalid, so you can't rely on it.
The main purpose of canoncialPath is to fix the case on Windows, so
c:\my documents\file.doc becomes C:\My Documents\file.doc if that
is the case correct version of the file. I think this function will
not actually change the file with relation to the underying file
system, so should be race free. (I will document more to make the
operation clearer)
We should avoid referring to $PATH as the path, since we
already have FilePath.
Agreed, but I couldn't come up with a better name, if anyone has any
suggestions.
search path seems the best option, I think.
Still has the Path in the name, which is the confusing bit, to me at least.
Has a FilePath of /usr/bin/ghc and a FileName of ghc.
Then this seems inconsistent with the naming of splitFileName, which should be
splitFilePath.
No, since its splits a FilePath into a FileName and the rest left
over. In the same way that splitExtension takes a FilePath, but splits
into an extension. I have named the operations by the result, rather
than the input (which is almost always a FilePath)
Isn't joinFilename the same as combine?
Yes, I hadn't spotted thats (the code is duplicated, and written in a
different style). However I feel its useful to have both of them in
there, since having the join/split duality is quite handy, and combine
conceptually operates on a lot more than just filenames.
get/setFilename are ok, but I prefer to reserve get/set for statelike things.
Perhaps instead:
directoryOf :: FilePath - String
filenameOf :: FilePath - String
extensionOf :: FilePath - String
basenaneOf :: FilePath - String
replaceFilename = joinFilePath . directoryOf
replaceDirectory = flip joinFilePath . filenameOf
I don't like directoryOf/replaceDirectory as names, since one has
Directory at the front and the other at the end. However I'm flexible
about this. Ideally I wanted to use the record constructors:
mypath{directory = value}
directory mypath.
Unfortunately that can't be done with FilePath = String, and even with
a separate constructor and records its not particularly nice to write.
(unfortunately this use of basename is inconsistent with the Unix command,
perhaps there's a better name?).
If anyone can think of one... Naming is not my strong point!
Thanks
Neil
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] RE: ANN: System.FilePath 0.9
Hi Its a rats nest to do it properly, but some very basic idea of does this path have things which there is no way could possibly be in a file - for example c:\|file is a useful thing to have. This seems to encourage the classic mistake of checking not known bad rather than known good. known bad is rarely useful in my experience. What use case do you have in mind? wget on windows saves web pages such as http://www.google.com/index.html?q=haskell; to the file index.html?q=haskell. This just doesn't work, and is the main reason I added this in. I don't think it will be a commonly used operation. The drive functions stand on their own as a chunk, and are possibly Why are they critical for portable code? I am fine with Windows-specific functions, but I think it's a mistake to bundle them portable functions. I agree, and have now removed them. My criticism is that your properties are all specified in terms of string manipulation. The whole point of paths is that they are interpreted by the system, so if you neglect to say what your operations mean to the system, what have you specified? True, but at the same time specifying what something means with respect to a filesystem is very hard :) If you had any insight how this could be done I'd be interested. pathSeparator :: Char The character that seperates directories. So what do I do with this? If I need it, it seems like the module has failed. Hopefully no one will ever use it. Its part of the low level functions that the FilePath module builds on. However, pragmatically, someone somewhere will have a use for it, and the second they do they'll just write '/', and at that point we've lost. splitFileName :: FilePath - (String, String) Split a filename into directory and file. Which directory and which file? Ok, thats probably the wrong description. Splits off the last filename would be a better description, leaving the rest. splitFileName bob == (, bob) is not a directory No, its the rest in this context. Windows: splitFileName c: == (c:,) c: is arguably not a directory. (Consider that dir c: lists the current directory on c:, not c:\) Its a bit weird on Windows, but certainly c: isn't a FileName, so thats the reason for this decision. getFileName test/ == is not a filename. But test/ is certainly not a file. Also, it looks from this that you treat paths differently depending on whether they end in a separator. Yet this makes no difference to the system. That seems wrong to me. That was something I thought over quite a while. If the user enters directory/ then they do not mean the file called directory, they mean the directory called directory. And in Windows certainly you can't open a file called file/ setFileName :: FilePath - String - FilePath Set the filename. This is vague to me. Eg, what does it do with /, which has no filename? / as the second element? I guess its calling it out of spec if you use anything but a valid filename as the second argument, and the behaviour is undefined. If you do need to do something like that, then combine is the function. getDirectory :: FilePath - FilePath Get the directory name, move up one level. What does this mean, in the presence of dots and symlinks? It gets a parent directory, there may be one, but the one returned will be a parent. normalise :: FilePath - FilePath Normalise a file As Simon asked, when is this safe to use? Let me think, and then work on it so the answer is always. equalFilePath :: FilePath - FilePath - Bool Equality of two FilePaths. If you call fullPath first this has a much better chance of working. Note that this doesn't follow symlinks or DOSNAM~1s. As you acknowledge, it's a crap-shoot. So what's the point? Its a case of reality, at the moment people use == to test if two file paths are equal, at least this is a better test. isValid :: FilePath - Bool Is a FilePath valid, i.e. could you create a file like it? There are a whole host of reasons you might not be able to create a file. Which ones does this address? I have added documentation which hopefully shows exactly what it tries to address. I think of that as a separate module, because extensions have no meaning to the system and can be done with portable, functional code, as far as I understand. Not really, what about getExtension file.ext\lump - the answer is on windows and .ext\lump on Posix. This library isn't just a portability layer (although it does encompass that), its mainly meant to make the things people do with filepaths easier, and by seducing them with ease of use, subtly tack in cross platform portability. Thanks Neil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
