[Haskell-cafe] How large is the Haskell community ?
I was wondering if anyone had an idea or estimate as to how large the Haskell community is ? Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How large is the Haskell community ?
On 12 February 2011 20:24, Don Stewart d...@galois.com wrote: aaronngray.lists: I was wondering if anyone had an idea or estimate as to how large the Haskell community is ? No one knows. There are many figures that you could use to estimate the size (e.g. I try to gather signifcant stats in yearly reports about Hackage) * In 2010, for example, 138,000 unique IPs downloaded the Haskell Platform. http://www.galois.com/~dons/talks/hiw-hackage-y2.pdf Right 138,000, but that would not account for gateways :| Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How large is the Haskell community ?
On 12 February 2011 21:31, Erik de Castro Lopo mle...@mega-nerd.com wrote: Aaron Gray wrote: On 12 February 2011 20:24, Don Stewart d...@galois.com wrote: aaronngray.lists: I was wondering if anyone had an idea or estimate as to how large the Haskell community is ? No one knows. There are many figures that you could use to estimate the size (e.g. I try to gather signifcant stats in yearly reports about Hackage) * In 2010, for example, 138,000 unique IPs downloaded the Haskell Platform. http://www.galois.com/~dons/talks/hiw-hackage-y2.pdf Right 138,000, but that would not account for gateways :| Or people who get Haskell related stuff via their Linux distribution (specifically Debian, Ubuntu and Fedora, but possibly others as well). Then there are people who download it, look at it and maybe find it too complex to use ? I am wondering if mailing list statistics would be the best guide ? Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How large is the Haskell community ?
On 12 February 2011 23:57, Jan Christiansen j...@informatik.uni-kiel.dewrote: On 12.02.2011, at 21:18, Aaron Gray wrote: I was wondering if anyone had an idea or estimate as to how large the Haskell community is ? All the answers made me wonder what the criterion is to be a member of the Haskell community. Are you a member if you downloaded ghc, if you have (at least once) defined a Monad instance, if you have written a hackage package, if you have contributed to the Monad.Reader, if you have a github account with at least one Haskell project, if you read at least one of the haskell mailing lists, if you contribute to a haskell mailing list (perhaps on a regular basis), if you post on reddit, if you answer/ask questions on stackoverflow, if you have written at least 1 lines of code in Haskell, if Haskell is one of the programming languages you use, if Haskell is the one programming language you use, if you have written a PhD thesis related to Haskell, if you have asked a type related question only Oleg Kiselyov was able to answer, if you know what a Monoid is and know how to use it ... ; ) Cheers, Jan Maybe we should have some website like the Linux Counter where you can get an official Haskell user number ? Then advertise it well. Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] A few days to go before the old server goes down
On 27 January 2011 22:42, Henk-Jan van Tuyl hjgt...@chello.nl wrote: L.S., Only four days until the old Haskell.org server disappears; I found the following missing: http://www.haskell.org/yale/ http://darcs.haskell.org/hfuse/ http://haskell.org/gtk2hs/ http://haskell.org/FranTk http://www.haskell.org/yampa/ http://www.haskell.org/visualhaskell/ http://haskell.org/~kolmodin http://haskell.org/graphics/ http://www.haskell.org/libraries/ http://haskell.org/hdirect/ http://haskell.org/haskore/ http://darcs.haskell.org/wxhaskell/ http://www.haskell.org/all_about_monads http://www.haskell.org/edsl/ http://www.haskell.org/jcp/ http://darcs.haskell.org/yaht http://cvs.haskell.org/darcs/ http://haskell.org/ObjectIO http://www.haskell.org/sitewiki/ http://darcs.haskell.org/~lemmih/ It would also be a shame if useful information would be lost, so copy the pages before it is too late! (The Wayback Machine has no recent copies, or even none at all for some pages.) If they have moved, it would be useful to know whereto, as several HaskellWiki pages have to be updated. Regards, Henk-Jan van Tuyl There also seems to be missing darcs repositories on :- code.haskell.org these do not seem to be accessible on :- code.oldhaskell.cs.yale.edu Is it possible to delay the switch off and to get the missing sub domains on oldhaskell.cs.yale.edu reinstated ? Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Tracing applied functions
Is there anyway to get a list of applied functions in the running of a Haskell program ? Many thanks in advance, Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Tracing applied functions
On 24 January 2011 23:01, Ivan Lazar Miljenovic ivan.miljeno...@gmail.comwrote: On 25 January 2011 02:55, Aaron Gray aaronngray.li...@gmail.com wrote: Is there anyway to get a list of applied functions in the running of a Haskell program ? Profile it? Okay, How do I do that ? Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Tracing applied functions
On 25 January 2011 02:12, Ivan Lazar Miljenovic ivan.miljeno...@gmail.comwrote: On 25 January 2011 12:05, Aaron Gray aaronngray.li...@gmail.com wrote: On 24 January 2011 23:01, Ivan Lazar Miljenovic ivan.miljeno...@gmail.com wrote: On 25 January 2011 02:55, Aaron Gray aaronngray.li...@gmail.com wrote Is there anyway to get a list of applied functions in the running of a Haskell program ? Profile it? Okay, How do I do that ? http://www.haskell.org/haskellwiki/How_to_profile_a_Haskell_program http://book.realworldhaskell.org/read/profiling-and-optimization.html Thanks I will have a look at those in the morning. Aaron -- 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] Data.Ranges show error
On 22 January 2011 13:15, Daniel Fischer daniel.is.fisc...@googlemail.comwrote: On Saturday 22 January 2011 03:47:55, Aaron Gray wrote: Data.Ranges.hs:12 show (Range x y) = concat [(, show x, –, show y, )] Contains the following charcter sequence :- – Which does not seem to be supported in Windows codepage. Aaron For me, that's an en-dash (U+2013 / '\8211'). I believe something on your box mangled the UTF-8 encoding. Weird I did a cabal install and have not touched it with an editor. Are you on Windows ? Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Flushing Cabal's cache
I am getting the following error :- C:\Languages\Lexer\Haskellcabal install ranges Resolving dependencies... cabal: Error: some packages failed to install: ranges-0.2.3 failed while unpacking the package. The exception was: user error (TAR checksum error) I am on Windows Vista, is it possible to clean or delete Cabal's cache ? Many thanks in advance, Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Data.Ranges show error
On 22 January 2011 16:31, Daniel Fischer daniel.is.fisc...@googlemail.comwrote: On Saturday 22 January 2011 17:01:00, Aaron Gray wrote: For me, that's an en-dash (U+2013 / '\8211'). I believe something on your box mangled the UTF-8 encoding. Weird I did a cabal install and have not touched it with an editor. Except to look at it trying to find the issue, I suppose (how else did you find the –)? I downloaded it separately from the HackageDB. What's your locale? Could also be that GHC tries to interpret UTF-8 in your locale and barfs on that. Not sure ? Vista's default. Are you on Windows ? No, linux. Ah How do I get Cabal to install a package from disk rather than from the internet ? Many thanks, Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Data.Ranges show error
On 22 January 2011 17:04, Daniel Fischer daniel.is.fisc...@googlemail.comwrote: On Saturday 22 January 2011 17:42:39, Aaron Gray wrote: What's your locale? Could also be that GHC tries to interpret UTF-8 in your locale and barfs on that. Not sure ? Vista's default. Which probably isn't UTF-8. There must be an analogue of locale on Windows to check. Not sure I thought it was UTF-8. Its behaving differently on different Vista machines. Are you on Windows ? No, linux. Ah How do I get Cabal to install a package from disk rather than from the internet ? If it's unpacked, just cd into the package directory and do a $ cabal install there (optionally provide further command line args, but not the package name) or $ runghc ./Setup.hs configure --user $ runghc ./Setup.hs build $ runghc ./Setup.hs install If it's a .tar.gz, I don't know if cabal already supports installing those from a specified location (i.e., not from hackage or its cache). Thanks, Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Data.Ranges show error
I am getting the following error when trying to do a show on a Ranges object
:-
C:\Languages\Haskellghci rangeTest.hs
GHCi, version 6.12.3: http://www.haskell.org/ghc/ :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Loading package ffi-1.0 ... linking ... done.
[1 of 1] Compiling Main ( rangeTest.hs, interpreted )
Ok, modules loaded: Main.
*Main main
Loading package array-0.3.0.1 ... linking ... done.
Loading package containers-0.3.0.0 ... linking ... done.
Loading package ranges-0.2.3 ... linking ... done.
Ranges [(37*** Exception: stdout: hPutChar: invalid argument (character is
not
in the code page)
*Main
I have attached the test source also :-
import Data.Ranges
test = (ranges [
range 32 33,
range 34 35,
range 37 39
])
main :: IO ()
main = do {
putStrLn (show test)
}
I am probably doing something fundermentaly wrong.
Many thanks in advance,
Aaron
rangeTest.hs
Description: Binary data
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Re: [Haskell-cafe] GHC.Ptr, Foreign.Storable, Data.Storable.Endian, looking for good examples of usage
On 11 January 2011 00:02, Antoine Latter aslat...@gmail.com wrote: On Mon, Jan 10, 2011 at 5:23 PM, Aaron Gray aaronngray.li...@gmail.com wrote: On 10 January 2011 22:30, Henning Thielemann lemm...@henning-thielemann.de wrote: John Lato schrieb: You could use my word24 package[1] (GHC only) to provide non-aligned 24-bit word and int types with Storable instances. You should be able to write a binary instance (or whatever blaze-builder needs) fairly simply from this. Little-endian only ATM, but BE could be added if necessary. Good to know that! However, I think for the original poster the binary package is perfect. This way he does not worry about unsafe peeking and poking around in memory. Yes. I have came back to looking at the binary package, the only thing is I think I have to build my own primatives with it as it is big-endian, where ActionScript Byte Code format is little-endian. It does provide some little-endian functions but they are not brought to the surface. It also seems to roll its own serializations. The 'binary' package supports big-endian, little-endian and host-endian construction in the Data.Binary.Builder module, so you hopefully won't need to reimplement too much. Are there any examples of usage anywhere ? It does not seem to have 24bit values either. I am still thinking of implementing my own following the straight Data.Binary package as an example. Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC.Ptr, Foreign.Storable, Data.Storable.Endian, looking for good examples of usage
On 11 January 2011 18:54, Antoine Latter aslat...@gmail.com wrote: On Tue, Jan 11, 2011 at 10:22 AM, Aaron Gray aaronngray.li...@gmail.com wrote: On 11 January 2011 00:02, Antoine Latter aslat...@gmail.com wrote: On Mon, Jan 10, 2011 at 5:23 PM, Aaron Gray aaronngray.li...@gmail.com wrote: On 10 January 2011 22:30, Henning Thielemann lemm...@henning-thielemann.de wrote: John Lato schrieb: You could use my word24 package[1] (GHC only) to provide non-aligned 24-bit word and int types with Storable instances. You should be able to write a binary instance (or whatever blaze-builder needs) fairly simply from this. Little-endian only ATM, but BE could be added if necessary. Good to know that! However, I think for the original poster the binary package is perfect. This way he does not worry about unsafe peeking and poking around in memory. Yes. I have came back to looking at the binary package, the only thing is I think I have to build my own primatives with it as it is big-endian, where ActionScript Byte Code format is little-endian. It does provide some little-endian functions but they are not brought to the surface. It also seems to roll its own serializations. The 'binary' package supports big-endian, little-endian and host-endian construction in the Data.Binary.Builder module, so you hopefully won't need to reimplement too much. Are there any examples of usage anywhere ? It does not seem to have 24bit values either. I am still thinking of implementing my own following the straight Data.Binary package as an example. Aaron I used Data.Binary.Builder in an implementation of the memcached binary protocol: http://hackage.haskell.org/packages/archive/starling/0.3.0/doc/html/Network-Starling-Core.html Nice code, I like the Serialize and Deserialize classes. Its a shame Data.Binary does not use them. I'm sure other folks can chime in with good examples if that one isn't clear - the package 'binary' is pretty popular. You'd have to write your own putWord24be/le or whatever you need out of the 'singleton :: Word8 - Builder' function. But that seems simpler than reimplementing Data.Binary. Yes. Thanks, Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC.Ptr, Foreign.Storable, Data.Storable.Endian, looking for good examples of usage
On 10 January 2011 13:49, John Lato jwl...@gmail.com wrote: From: Aaron Gray aaronngray.li...@gmail.com On 9 January 2011 21:30, Henning Thielemann lemm...@henning-thielemann.dewrote: On Sun, 9 Jan 2011, Aaron Gray wrote: I am trying to work out how to use GHC.Ptr, Foreign.Storable, Data.Storable.Endian, and am looking for good examples of usage. What do you intend to do with them? An (ABC) ActionScript Byte Code backend for Haskell. Basically I need to write little-endian binary to a file, and was wondering the best way to do this; I need various types including a 24bit type. You could use my word24 package[1] (GHC only) to provide non-aligned 24-bit word and int types with Storable instances. You should be able to write a binary instance (or whatever blaze-builder needs) fairly simply from this. Little-endian only ATM, but BE could be added if necessary. John Lato [1] http://hackage.haskell.org/package/word24 This is interesting, what does the following line do :- data Int24 = I24# Int# deriving (Eq, Ord) regarding the I24# and Int#, are these inbuilt ? Thanks, Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC.Ptr, Foreign.Storable, Data.Storable.Endian, looking for good examples of usage
On 10 January 2011 16:13, Daniel Fischer daniel.is.fisc...@googlemail.comwrote: On Monday 10 January 2011 16:45:36, Aaron Gray wrote: This is interesting, what does the following line do :- data Int24 = I24# Int# deriving (Eq, Ord) regarding the I24# and Int#, are these inbuilt ? Int# is the raw machine int (4 or 8 bytes) and I24# is the constructor. GHC uses the magic hash '#' to denote raw unboxed types (and the constructors making ordinary boxed Haskell types from these, e.g. there's data Int = I# Int# data Word = W# Word# data Double = D# Double# and more defined in base [GHC.Types, GHC.Word]). So the 24 bit value is actually stored as a 32bit value. Meaning I will have to do my own IO reader and writer code to a ByteString. Thanks, Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC.Ptr, Foreign.Storable, Data.Storable.Endian, looking for good examples of usage
On 10 January 2011 16:36, Antoine Latter aslat...@gmail.com wrote: On Mon, Jan 10, 2011 at 10:17 AM, Aaron Gray aaronngray.li...@gmail.com wrote: On 10 January 2011 16:13, Daniel Fischer daniel.is.fisc...@googlemail.com wrote: On Monday 10 January 2011 16:45:36, Aaron Gray wrote: This is interesting, what does the following line do :- data Int24 = I24# Int# deriving (Eq, Ord) regarding the I24# and Int#, are these inbuilt ? Int# is the raw machine int (4 or 8 bytes) and I24# is the constructor. GHC uses the magic hash '#' to denote raw unboxed types (and the constructors making ordinary boxed Haskell types from these, e.g. there's data Int = I# Int# data Word = W# Word# data Double = D# Double# and more defined in base [GHC.Types, GHC.Word]). So the 24 bit value is actually stored as a 32bit value. Meaning I will have to do my own IO reader and writer code to a ByteString. Thanks, Aaron I don't think so - the Storable instance provided for the Int24 type peeks and pokes 24-bit values. At least, that what I understand John's earlier message to mean. Yes looking at the code it does support 24bit peeks and pokes. Thanks, Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC.Ptr, Foreign.Storable, Data.Storable.Endian, looking for good examples of usage
On 10 January 2011 22:30, Henning Thielemann lemm...@henning-thielemann.dewrote: John Lato schrieb: You could use my word24 package[1] (GHC only) to provide non-aligned 24-bit word and int types with Storable instances. You should be able to write a binary instance (or whatever blaze-builder needs) fairly simply from this. Little-endian only ATM, but BE could be added if necessary. Good to know that! However, I think for the original poster the binary package is perfect. This way he does not worry about unsafe peeking and poking around in memory. Yes. I have came back to looking at the binary package, the only thing is I think I have to build my own primatives with it as it is big-endian, where ActionScript Byte Code format is little-endian. It does provide some little-endian functions but they are not brought to the surface. It also seems to roll its own serializations. I am maybe looking at doing my own specialized set of types and binary backend as there are drawback with each of the existing solutions. - Data.Storable.Endian - peeks and pokes rather than put/get - Data.Word24 - peeks and pokes rather than put/get - Data.Binary - big-endian ABC format may best be supported by a specific set of serialization types. On a different note thinking outside this problem, I would like IO_LE and IO_BE types if that could be make to work. Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] GHC.Ptr, Foreign.Storable, Data.Storable.Endian, looking for good examples of usage
Hi, I am trying to work out how to use GHC.Ptr, Foreign.Storable, Data.Storable.Endian, and am looking for good examples of usage. Many thanks in advance, Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC.Ptr, Foreign.Storable, Data.Storable.Endian, looking for good examples of usage
On 9 January 2011 22:34, Henk-Jan van Tuyl hjgt...@chello.nl wrote: On Sun, 09 Jan 2011 14:48:09 +0100, Aaron Gray aaronngray.li...@gmail.com wrote: Hi, I am trying to work out how to use GHC.Ptr, Foreign.Storable, Data.Storable.Endian, and am looking for good examples of usage. Many thanks in advance, Aaron You can lookup, which packages use these, by looking at the reverse dependencies: http://bifunctor.homelinux.net/~roel/hackage/packages/archive/pkg-list.html Handy I did not notice that, nice. Thanks, Aaron Regards, Henk-Jan van Tuyl -- http://Van.Tuyl.eu/ http://members.chello.nl/hjgtuyl/tourdemonad.html -- ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC.Ptr, Foreign.Storable, Data.Storable.Endian, looking for good examples of usage
On 9 January 2011 21:30, Henning Thielemann lemm...@henning-thielemann.dewrote: On Sun, 9 Jan 2011, Aaron Gray wrote: I am trying to work out how to use GHC.Ptr, Foreign.Storable, Data.Storable.Endian, and am looking for good examples of usage. What do you intend to do with them? An (ABC) ActionScript Byte Code backend for Haskell. Basically I need to write little-endian binary to a file, and was wondering the best way to do this; I need various types including a 24bit type. The package storablevector uses a lot of Ptr, peek, and poke. Maybe this is of some help. Okay thanks, Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC.Ptr, Foreign.Storable, Data.Storable.Endian, looking for good examples of usage
On 10 January 2011 01:08, Antoine Latter aslat...@gmail.com wrote: On Sun, Jan 9, 2011 at 6:05 PM, Aaron Gray aaronngray.li...@gmail.com wrote: On 9 January 2011 21:30, Henning Thielemann lemm...@henning-thielemann.de wrote: On Sun, 9 Jan 2011, Aaron Gray wrote: I am trying to work out how to use GHC.Ptr, Foreign.Storable, Data.Storable.Endian, and am looking for good examples of usage. What do you intend to do with them? An (ABC) ActionScript Byte Code backend for Haskell. Basically I need to write little-endian binary to a file, and was wondering the best way to do this; I need various types including a 24bit type. Ah, I would recommend the 'binary' package on hackage, specifically the module Data.Binary.Builder. Another recently popular alternative is the 'blaze-builder' package. It does say that it is designed to work with bigendian data, but there are some little-endian primatives in Data.Binary.Get/Put Although the 24-bit access might be difficult - how are they aligned? They are non aligned, they are actually used as jump offsets in the byte code. I guess with either of these you'd have to peek a Word8 and then a Word16 and then munge them together, depending. Three put/getWord8's would probably be neater. http://hackage.haskell.org/package/binary http://hackage.haskell.org/package/blaze-builder Blaze looks a bit more specialized. Many thanks, Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Happy Parser problem
I am trying to get a grammar where keywords are also valid identifiers.
Been messing round with the following Happy grammar :-
%token
'let' { TokenIdent let }
'in'{ TokenIdent in }
ident { TokenIdent $$ }
int { TokenInt $$ }
'=' { TokenEq }
'+' { TokenPlus }
'-' { TokenMinus }
'*' { TokenTimes }
'/' { TokenDiv }
'(' { TokenOB }
')' { TokenCB }
%%
Exp : 'let' Var '=' Exp 'in' Exp { Let $2 $4 $6 }
| Exp1{ Exp1 $1 }
Exp1 : Exp1 '+' Term { Plus $1 $3 }
| Exp1 '-' Term { Minus $1 $3 }
| Term{ Term $1 }
Term : Term '*' Factor { Times $1 $3 }
| Term '/' Factor { Div $1 $3 }
| Factor { Factor $1 }
Factor :: { Factor }
: int { Int $1 }
| ident { Var $1 }
| '(' Exp ')' { Brack $2 }
Var :: { Factor }
: ident { Var $1 }
| 'let' { Var let }
Here 'Var' should be able to represent a 'let' identifier, as well as a
keyword. Happy accepts the grammar but it does not parser the expected 'let
let = x in let'.
I have attached the full Happy grammar.
I don't think this is an LR thing, but could be wrong.
Many thanks in advance,
Aaron
exprtree.y
Description: Binary data
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Re: [Haskell-cafe] Happy Parser problem
On 31 December 2010 13:21, Aaron Gray aaronngray.li...@gmail.com wrote:
I am trying to get a grammar where keywords are also valid identifiers.
Sorry working now !
Aaron
Been messing round with the following Happy grammar :-
%token
'let' { TokenIdent let }
'in'{ TokenIdent in }
ident { TokenIdent $$ }
int { TokenInt $$ }
'=' { TokenEq }
'+' { TokenPlus }
'-' { TokenMinus }
'*' { TokenTimes }
'/' { TokenDiv }
'(' { TokenOB }
')' { TokenCB }
%%
Exp : 'let' Var '=' Exp 'in' Exp { Let $2 $4 $6 }
| Exp1{ Exp1 $1 }
Exp1 : Exp1 '+' Term { Plus $1 $3 }
| Exp1 '-' Term { Minus $1 $3 }
| Term{ Term $1 }
Term : Term '*' Factor { Times $1 $3 }
| Term '/' Factor { Div $1 $3 }
| Factor { Factor $1 }
Factor :: { Factor }
: int { Int $1 }
| ident { Var $1 }
| '(' Exp ')' { Brack $2 }
Var :: { Factor }
: ident { Var $1 }
| 'let' { Var let }
Here 'Var' should be able to represent a 'let' identifier, as well as a
keyword. Happy accepts the grammar but it does not parser the expected 'let
let = x in let'.
I have attached the full Happy grammar.
I don't think this is an LR thing, but could be wrong.
Many thanks in advance,
Aaron
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[Haskell-cafe] getting last char of String
Is there an easy Haskell function that gets the last Char of a [Char] or String ? Many thanks in advance, Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] getting last char of String
On 31 December 2010 20:44, Matthew Steele mdste...@alum.mit.edu wrote: Sounds like you're looking for `last', which is in the Prelude. Yep, feeling dumb I did not try it ! Thanks, Aaron http://www.haskell.org/ghc/docs/6.12.2/html/libraries/base-4.2.0.1/Prelude.html#v%3Alast Cheers, -Matt On Dec 31, 2010, at 3:39 PM, Aaron Gray wrote: Is there an easy Haskell function that gets the last Char of a [Char] or String ? Many thanks in advance, Aaron ___ 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
[Haskell-cafe] Could someone give me a small code review
I have attached a tiny parser and lexer. This is really key to getting the lexing correct. The only thing I could not get neatly was to disallow hyphens at the end of identifiers, so have left it off until a good solution arrives. I plan to move over to monads next. Any comments welcome, Aaron exprtree.y Description: Binary data ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Could someone give me a small code review
On 31 December 2010 21:26, Aaron Gray aaronngray.li...@gmail.com wrote: I have attached a tiny parser and lexer. This is really key to getting the lexing correct. The only thing I could not get neatly was to disallow hyphens at the end of identifiers, so have left it off until a good solution arrives. I plan to move over to monads next. Any comments welcome, Oh forgot parenthesis, brackets and braces, theres a new attachment for them. Then there's comments to do... Aaron exprtree.y Description: Binary data ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] record types and unique names
Given a Haskell record type :-
data Test
= Test {
name :: String,
value :: Int
}
test = Test {
name = test,
value = 1
}
main :: IO ()
main = do
putStrLn (name test)
Are name and value in the global name space, as the following gives an
error Multiple declarations of `name' :-
name :: String - String
name s = s
Is there any way round this ?
Many thanks in advance,
Aaron
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Re: [Haskell-cafe] record types and unique names
On 30 December 2010 17:23, Markus Läll markus.l...@gmail.com wrote:
Yes, they are in the global scope, and from what I gather: they are just
regular functions, created by special syntax.
There are a few obvious solutions (some of which you might have thought
yourself :-):
- rename the accessor or the other function, or
- put the data declaration or the other function in another module and
import qualified, or
- write a typeclass with a 'name' function and fit the non-accessor
function 'name' somehow into that...
I think the best approach is the modular one, but this really depends on
what you are doing.
Okay looks like name mangling with the datatypes name is in order then.
Something like :-
data Test
= Test {
testName :: String,
testValue :: Int
}
Thanks,
Aaron
--
Markus Läll
On Thu, Dec 30, 2010 at 7:01 PM, Aaron Gray aaronngray.li...@gmail.comwrote:
Given a Haskell record type :-
data Test
= Test {
name :: String,
value :: Int
}
test = Test {
name = test,
value = 1
}
main :: IO ()
main = do
putStrLn (name test)
Are name and value in the global name space, as the following gives an
error Multiple declarations of `name' :-
name :: String - String
name s = s
Is there any way round this ?
Many thanks in advance,
Aaron
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Re: [Haskell-cafe] record types and unique names
On 30 December 2010 17:29, aditya siram aditya.si...@gmail.com wrote:
I don't think record field disambiguation what you're after. My apologies.
-deech
Interesting never the less.
Thanks,
Aaron
On Thu, Dec 30, 2010 at 11:20 AM, aditya siram aditya.si...@gmail.com
wrote:
Take a look at the record field disambiguation [1] extension to GHC.
It sounds like what you're looking for.
-deech
[1]
http://www.haskell.org/ghc/docs/6.12.2/html/users_guide/syntax-extns.html#disambiguate-fields
On Thu, Dec 30, 2010 at 11:01 AM, Aaron Gray aaronngray.li...@gmail.com
wrote:
Given a Haskell record type :-
data Test
= Test {
name :: String,
value :: Int
}
test = Test {
name = test,
value = 1
}
main :: IO ()
main = do
putStrLn (name test)
Are name and value in the global name space, as the following gives
an
error Multiple declarations of `name' :-
name :: String - String
name s = s
Is there any way round this ?
Many thanks in advance,
Aaron
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[Haskell-cafe] What are these comments for {-# SCC Mangler #-}
What are these comments for in Happy ?
{-# SCC Mangler #-}
Many thanks in advance,
Aaron
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Re: [Haskell-cafe] instance for (Show ([(String, Int)] - Int))
On 24 December 2010 23:58, Daniel Fischer daniel.is.fisc...@googlemail.comwrote: On Saturday 25 December 2010 00:32:38, Aaron Gray wrote: Okay great, works this end too, but what does the 'flip' do ??? It flips the order of arguments to calc. You could also write main = getContents = print . (`calc` []) . lexer Generally, flip f = \x y - f y x or flip f x = \y - f y x flip f x y = f y x Thanks Daniel, Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] instance for (Show ([(String, Int)] - Int))
On 24 December 2010 23:58, Daniel Fischer daniel.is.fisc...@googlemail.comwrote: On Saturday 25 December 2010 00:32:38, Aaron Gray wrote: Okay great, works this end too, but what does the 'flip' do ??? It flips the order of arguments to calc. You could also write main = getContents = print . (`calc` []) . lexer Generally, flip f = \x y - f y x or flip f x = \y - f y x flip f x y = f y x Or :- calcExpr :: [Token] - Int calcExpr tokens = calc tokens [] process = print . calcExpr . lexer makes things clearer. Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANNOUNCE: storable-endian
Hi Eugene, I have been looking to do a ActionScript backend, it needs 24bit values. Would it be possible to add some 24bit peeks and pokes, please. Aaron On 26 December 2010 11:13, Eugene Kirpichov ekirpic...@gmail.com wrote: So I got around to it. storable-endian 0.2.3 released, see code: https://github.com/jkff/storable-endian/blob/master/Data/Storable/Endian.hs There's some boilerplate there, but I think it's tractable. 2010/12/25 Eugene Kirpichov ekirpic...@gmail.com: Thanks! Now I'll use it in storable-endian as soon as I get around to it :) 2010/12/25 Antoine Latter aslat...@gmail.com: On Sat, Dec 25, 2010 at 1:31 AM, Eugene Kirpichov ekirpic...@gmail.com wrote: Great! Antoine, would you perhaps then update the cabal description of the package to include the word endianness in it? I Ctrl+F-ed endian through hackage before writing storable-endian and did not find your package. It is done! Although I spelled it wrong on my first try. Take care, Antoine 2010/12/25 Antoine Latter aslat...@gmail.com: On Fri, Dec 24, 2010 at 8:08 AM, Henk-Jan van Tuyl hjgt...@chello.nl wrote: You could use ADNS.Endian.endian from package hsdns in your Setup.hs to define endianness at compile time. Regards, Henk-Jan van Tuyl It looks like I've reimplemented the same thing in its own package: http://hackage.haskell.org/package/byteorder With pretty much the same technique. Take care, Antoine -- Eugene Kirpichov Senior Software Engineer, Grid Dynamics http://www.griddynamics.com/ -- Eugene Kirpichov Senior Software Engineer, Grid Dynamics http://www.griddynamics.com/ -- Eugene Kirpichov Senior Software Engineer, Grid Dynamics http://www.griddynamics.com/ ___ 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
[Haskell-cafe] instance for (Show ([(String, Int)] - Int))
How do I code an 'instance' declaration for '(Show ([(String, Int)] - Int))'. I am new to instance declarations and am following the Happy examples :- http://www.haskell.org/happy/doc/html/sec-using.html#sec-other-datatypes The compiler is requesting an instance declaration for Show :- expr-eval.hs:334:23: No instance for (Show ([(String, Int)] - Int)) arising from a use of `print' at expr-eval.hs:334:23-27 Possible fix: add an instance declaration for (Show ([(String, Int)] - Int)) In the first argument of `(.)', namely `print' In the second argument of `(=)', namely `print . calc . lexer' In the expression: getContents = print . calc . lexer Many thanks in advance, Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] instance for (Show ([(String, Int)] - Int))
On 24 December 2010 18:24, Henning Thielemann lemm...@henning-thielemann.de wrote: On Fri, 24 Dec 2010, Aaron Gray wrote: The compiler is requesting an instance declaration for Show :- expr-eval.hs:334:23: No instance for (Show ([(String, Int)] - Int)) arising from a use of `print' at expr-eval.hs:334:23-27 Possible fix: add an instance declaration for (Show ([(String, Int)] - Int)) In the first argument of `(.)', namely `print' In the second argument of `(=)', namely `print . calc . lexer' In the expression: getContents = print . calc . lexer ... maybe 'calc' needs a further argument? I have attached what I have typed in so far. Aaron expr-eval.y Description: Binary data expr-tree.y Description: Binary data ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] instance for (Show ([(String, Int)] - Int))
On 24 December 2010 22:07, Daniel Fischer daniel.is.fisc...@googlemail.comwrote: On Friday 24 December 2010 22:47:55, Aaron Gray wrote: On 24 December 2010 18:24, Henning Thielemann lemm...@henning-thielemann.de wrote: On Fri, 24 Dec 2010, Aaron Gray wrote: The compiler is requesting an instance declaration for Show :- expr-eval.hs:334:23: No instance for (Show ([(String, Int)] - Int)) arising from a use of `print' at expr-eval.hs:334:23-27 Possible fix: add an instance declaration for (Show ([(String, Int)] - Int)) In the first argument of `(.)', namely `print' In the second argument of `(=)', namely `print . calc . lexer' In the expression: getContents = print . calc . lexer ... maybe 'calc' needs a further argument? I have attached what I have typed in so far. Well, *ExprEval :t calc calc :: [Token] - [(String, Int)] - Int calc needs an environment (a dictionary of let-bound names), which you have to provide. main = print . flip calc [] . lexer works fine. Okay great, works this end too, but what does the 'flip' do ??? Now to get it to work as a REPL and to read from file :) Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Windows Haskell Platform download link is broken
Windows Haskell Platform download link goes nowhere :- http://hackage.haskell.org/platform/windows.html The Download Haskell for Windows is broken :- http://lambda.galois.com/hp-tmp/2010.2.0.0/HaskellPlatform-2010.2.0.0-setup.exe Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Missing Parsec library in latest stable GHC
Missing Parsec library :- scheme.o(.text+0x4fa):fake: undefined reference to `parseczm2zi1zi0zi0_TextziParserCombinatorsziParsecziCombinator_skipMany1_closure' scheme.o(.text+0x501):fake: undefined reference to `parseczm2zi1zi0zi0_TextziPaserCombinatorsziParsecziChar_space_closure' scheme.o(.text+0x5c2):fake: undefined reference to `parseczm2zi1zi0zi0_TextziParserCombinatorsziParsecziChar_oneOf_closure' scheme.o(.text+0x63a):fake: undefined reference to `mtlzm1zi1zi0zi0_ControlziMonadziTrans_zdf1_closure' GHC from :- http://www.haskell.org/ghc/dist/stable/dist/ ghc-7.0.1.20101221-i386-windows.exehttp://www.haskell.org/ghc/dist/stable/dist/ghc-7.0.1.20101221-i386-windows.exe and earlier. Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Latest Haskell Platform for Windows
Could someone please point me at a copy of the latest Haskell platform or a working GHC please. Many thanks in advance, Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Latest Haskell Platform for Windows
On 22 December 2010 16:41, Don Stewart d...@galois.com wrote: aaronngray.lists: Could someone please point me at a copy of the latest Haskell platform or a working GHC please. Many thanks in advance, The links on haskell.org/platform should work (there was a domain change, so you'll no longer see lambda.galois.com links). Okay, thanks. I obviously came along at the wrong time :) Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Missing Parsec library in latest stable GHC
On 22 December 2010 16:27, Antoine Latter aslat...@gmail.com wrote: What commands did you enter to produce this error? ghc scheme.hs I am still getting this on the 2010 2.0.0 release. Aaron Ahanks, Antoine On Wed, Dec 22, 2010 at 9:54 AM, Aaron Gray aaronngray.li...@gmail.com wrote: Missing Parsec library :- scheme.o(.text+0x4fa):fake: undefined reference to `parseczm2zi1zi0zi0_TextziParserCombinatorsziParsecziCombinator_skipMany1_closure' scheme.o(.text+0x501):fake: undefined reference to `parseczm2zi1zi0zi0_TextziPaserCombinatorsziParsecziChar_space_closure' scheme.o(.text+0x5c2):fake: undefined reference to `parseczm2zi1zi0zi0_TextziParserCombinatorsziParsecziChar_oneOf_closure' scheme.o(.text+0x63a):fake: undefined reference to `mtlzm1zi1zi0zi0_ControlziMonadziTrans_zdf1_closure' GHC from :- http://www.haskell.org/ghc/dist/stable/dist/ ghc-7.0.1.20101221-i386-windows.exe and earlier. Aaron ___ 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] Missing Parsec library in latest stable GHC
On 22 December 2010 16:47, Antoine Latter aslat...@gmail.com wrote: ghc doesn't, by default, go searching for packages to link in to the resulatant executable.. If you try 'ghc --make scheme.hs' your example will work better. Are great, thanks a lot. You can also specify what to link manually, but --make works pretty well most of the time. In ghc version 7 '--make' is the default, but until that's more widely distributed you'll want to get used to using the switch. Yes it was linking before I upgraded GHC, hence my confusion :) Many thanks Antoine, Aaron Take care, Antoine On Wed, Dec 22, 2010 at 10:36 AM, Aaron Gray aaronngray.li...@gmail.com wrote: On 22 December 2010 16:27, Antoine Latter aslat...@gmail.com wrote: What commands did you enter to produce this error? ghc scheme.hs Aaron Ahanks, Antoine On Wed, Dec 22, 2010 at 9:54 AM, Aaron Gray aaronngray.li...@gmail.com wrote: Missing Parsec library :- scheme.o(.text+0x4fa):fake: undefined reference to `parseczm2zi1zi0zi0_TextziParserCombinatorsziParsecziCombinator_skipMany1_closure' scheme.o(.text+0x501):fake: undefined reference to `parseczm2zi1zi0zi0_TextziPaserCombinatorsziParsecziChar_space_closure' scheme.o(.text+0x5c2):fake: undefined reference to `parseczm2zi1zi0zi0_TextziParserCombinatorsziParsecziChar_oneOf_closure' scheme.o(.text+0x63a):fake: undefined reference to `mtlzm1zi1zi0zi0_ControlziMonadziTrans_zdf1_closure' GHC from :- http://www.haskell.org/ghc/dist/stable/dist/ ghc-7.0.1.20101221-i386-windows.exe and earlier. Aaron ___ 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] Missing Parsec library in latest stable GHC
On 22 December 2010 16:51, Daniel Fischer daniel.is.fisc...@googlemail.comwrote: On Wednesday 22 December 2010 16:54:04, Aaron Gray wrote: Missing Parsec library :- scheme.o(.text+0x4fa):fake: undefined reference to `parseczm2zi1zi0zi0_TextziParserCombinatorsziParsecziCombinator_skipMany 1_closure' scheme.o(.text+0x501):fake: undefined reference to `parseczm2zi1zi0zi0_TextziPaserCombinatorsziParsecziChar_space_closure' scheme.o(.text+0x5c2):fake: undefined reference to `parseczm2zi1zi0zi0_TextziParserCombinatorsziParsecziChar_oneOf_closure' scheme.o(.text+0x63a):fake: undefined reference to `mtlzm1zi1zi0zi0_ControlziMonadziTrans_zdf1_closure' GHC from :- http://www.haskell.org/ghc/dist/stable/dist/ ghc-7.0.1.20101221-i386-windows.exehttp://www.haskell.org/ghc/dist/stab le/dist/ghc-7.0.1.20101221-i386-windows.exe and earlier. Aaron Since 6.8 iirc, GHC no longer comes with parsec, you have to install the package yourself if you want to use it, cabal install parsec This does not seem to be needed. import Text.ParserCombinators.Parsec seems fine. also mtl is no longer one of the libraries that come with GHC, cabal install mtl What is mtl ? Thanks, Aaron HTH, Daniel ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Problem with class Control.Monad.Error noMsg usage
I have been trying to build the Scheme in 24 Hours on WikiBooks :- http://en.wikibooks.org/wiki/Write_Yourself_a_Scheme_in_48_Hours http://jonathan.tang.name/files/scheme_in_48/code/listing10.hs But I am getting an error :- scheme.hs:289:6: `noMsg' is not a (visible) method of class `Error' scheme.hs:290:6: `strMsg' is not a (visible) method of class `Error' with the following :- instance Error LispError where noMsg = Default An error has occurred strMsg = Default if I try importing them :- import Control.Monad.Error (noMsg, strMsg) I get the following :- scheme.hs:4:29: Module `Control.Monad.Error' does not export `noMsg' scheme.hs:4:36: Module `Control.Monad.Error' does not export `strMsg' Many thanks in advance, Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Problem with class Control.Monad.Error noMsg usage
On 21 December 2010 15:40, Henning Thielemann schlepp...@henning-thielemann.de wrote: Aaron Gray schrieb: if I try importing them :- import Control.Monad.Error (noMsg, strMsg) I think it was moved to Control.Monad.Error.Class. Great, importing Control.Monad.Error.Class does the trick. Thanks, Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] REPL loop
Is it possible to implement a REPL (Read-eval-print loop) in Haskell ? Many thanks in advance, Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Musings on type systems
On 19 November 2010 22:14, Albert Y. C. Lai tre...@vex.net wrote: On 10-11-19 04:39 PM, Matthew Steele wrote: TAPL is also a great book for getting up to speed on type theory: http://www.cis.upenn.edu/~bcpierce/tapl/ I am no type theorist, and I nonetheless found it very approachable. TAPL is surprisingly easy-going. It is long (many pages and many chapters, each chapter short), but it is the good kind of long: long but gradual ramp to get you to the hard stuff. Its first chapter explains convincingly why you should care about types to begin with (summary: a lightweight formal method). But it is not entirely for Haskell. It covers subtyping, and it doesn't cover type classes. It is also too bulky to be mobile (because it's long). IIRC It Does not deal Hindley-Milner type system at all. i.e. it does not cover ML's type system. Its successor ATTAPL :- http://www.cis.upenn.edu/~bcpierce/attapl/index.html Handles an ML like type systems using constraints. AFAICT This area area of type theory's history is not covered properly in any of the sources I have came across. Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] borked windows environment, want to start over
On 17 November 2010 15:47, Henk-Jan van Tuyl hjgt...@chello.nl wrote: On Wed, 17 Nov 2010 01:39:40 +0100, Michael Litchard mich...@schmong.org wrote: I think I may have borked things good using cygwin. I want to remove it and do a clean install of haskell platform w/out cygwin. What do I need to do to make sure all configuration files have been removed? There are not many Cygwin experts here, I think, but it seems the answer can be found at: http://www.cygwin.com/faq/faq-nochunks.html#faq.setup.uninstall-all AFAICT Just don't use Cygwin. Install Windows Haskell from the Haskell.org web site download. Then run from Windows command line. You may have to put the haskell bin directory on the Windows PATH. Although I think it does this itself on instillation. Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Gödel's System T
On 11 November 2010 11:43, Petr Pudlak d...@pudlak.name wrote: Thanks Dan, the book is really interesting, all parts of it. It looks like I'll read the whole book. Watch out for the decidability issue though :- http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.6.6483 Aaron Best regards, Petr On Wed, Nov 10, 2010 at 05:21:16PM -0500, Dan Doel wrote: On Wednesday 10 November 2010 1:42:00 pm Petr Pudlak wrote: I was reading the paper Total Functional Programming [1]. I encountered an interesting note on p. 759 that primitive recursion in a higher-order language allows defining much larger set of function than classical primitive recursion (which, for example, cannot define Ackermann's function). And that this is studied in in Gödel's System T. It also states that this larger set of primitive functions includes all functions whose totality can be proved in first order logic. I was searching the Internet but I couldn't find a resource (a paper, a book) that would explain this in detail, give proofs etc. I'd be happy if someone could give me some directions. Girard's book, Proofs and Types, has some stuff on System T. A translation is freely available: http://www.paultaylor.eu/stable/Proofs+Types.html Skimming, it looks like he gives an argument that T can represent all functions that are provably total in Peano arithmetic. The rest of the book is also excellent. -- Dan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.10 (GNU/Linux) iQEcBAEBAgAGBQJM29b+AAoJEC5dcKNjBzhn7CAH/1DYIpZcWenZs4D+cPW2V9+F oET+abW2MgdRPPRquDT4qd/nLnI4XhTiiJEZq8mwfAY4OXBUjHnXLKTlKWyHkgCH zIRPIXWj0PSHNX+2yAB7muhWmOJv/BfrS9DOKsUDF3Qirtl9kc9x9SkWkVuRe2Yf JSAp+biYQkTSQg2MntHuprqTn783lfsLyKOvtNkybk3Kt+Ft7dzPmQgtgXCd5fPm eKI1D3b5H5NOH4cwYYUKejpc+8mptTdJVy6Hw8USI4e+hnoe62CZ/2bBf/lOyoCB UwNJ09sT5yepyA2DimvI3yZX33OB/K24xfPhsnvHaWAHyz3AkdeMG21eertnmtM= =zOw9 -END PGP SIGNATURE- ___ 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
[Haskell-cafe] ActionScript Byte Code backend ?
Is there a Flash ActionScript Byte Code generating backend for Haskell ? I know there was an older SWF 3 backend :- http://www.n-heptane.com/nhlab/repos/haskell-swf/ But is there anything more up to date ? Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] [ANNAUNCE] ghcjs-0.1.0 Haskell to Javascript compiler
On 27 October 2010 13:30, Martijn Schrage mart...@oblomov.com wrote: On 21-10-10 01:01, Victor Nazarov wrote: This example creates a text field that turns red if it contains any non-digit characters. It is on-line at http://tryout.oblomov.com/ghcjs/ghcjs.html (Note: I only tested it on Firefox on a Mac) All used files are in a zip file at http://tryout.oblomov.com/ghcjs/ghcjs.zip (validate is in Test.hs, the JS monad in JS.hs, and the JavaScript for execHaskell in util.js) What browser are you using, IE8, IE9, FF and Chrome on Windows throw up errors, both locally and to your above code. Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Windows binary for latest darcs head
Does anyone have a Windows binary for the latest GHC darcs head or at least October 8th they could send me. Many thanks in advance, Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Regular Expression to Determinate Finite Automata translator
Hi, I am a Haskell newbie. I have coded a Regular Expression to Determinate Finite Automata translator. Algorithm from the Dragon Book. Would someone eyeball the code and give me suggestions please. I have not done anything on character classes yet though. And the parsing is a bit of a hack. What I am not sure about is having to have multiple versions of similar datatype, each with variations in order to enumerate and generate followPos set. Is there a better way of implementing this ? Many thanks in advance, Aaron RE2DFA.hs Description: Binary data ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Typing Haskell in Haskell
Hi, I am relatively new to Haskell. I am attempting to get Typing Haskell in Haskell to work on HUGS or GHC. http://web.cecs.pdx.edu/~mpj/thih/ I am getting an error on loading SourcePrelude :- Hugs :l SourcePrelude ERROR .\PPrint.hs - Can't find imported module Pretty And I cannot find a Pretty module, the module and Language.Haskell.Pretty does not seem to be what is required. Any help welcome, Aaron ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
