Re: [Haskell-cafe] regex libraries: matching operators (=~) and (=~~) are not methods
On Tue, Nov 30, 2010 at 05:50:02PM -0200, José Romildo Malaquias wrote: Hello. When learning how to use the many regular expression libraries for Haskell, I noticed that the interface API from the regex-base package introduces several high level operations that are abstracted from the implementations (backends). This is done by means of classes. For instance, there are methods for compiling an external representation (like a string or a bytestring) into a regular expression. There are also methods for matching a regular expression and some text (like a string, or a bytestring). But the most high level functions for pattern matching using regular expressions, (=~) and (=~~), are not defined as methods in a class. They are independent functions defined for each backend in the corresponding package. This prevents one from writing a general function using these operators without deliberately choosing a regex backend. Why are those operators not defined as methods, like all other relevant functions? I think I have found the reason for that. Let's consider the operator (=~ ). Its type in the Text.Regex.TDFA is: ( RegexMaker Regex CompOption ExecOption source , RegexContext Regex source1 target ) = source1 - source - target It has two arguments: the text and the regex (in a textual format) used in matching. They may be both of type String, or ByteString, for instance. Therefore there is no way to infer which regex engine to use when the regex text is compiled to an internal format. So the regex engine cannot be deduced automatically from the arguments. Because of that each regex backend has to define his own function, and a class is of no help. Romildo ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Out of memory if compiled with -O2, why?
Hello Jason, Wednesday, December 1, 2010, 8:54:58 PM, you wrote: I'm using ghc7 here. If I run your program with -O2, it takes 1943 MB of memory max. If I comment out everything except g then with -O2 it takes 1521 MB. I'm not sure where the extra 400 MB of memory are going. i think, it's because memory isn't collected immediately, so in first case you just have more garbage hanging around. if you need to measure real workset of your program, you should apply very aggressive (and slow) garbage collection settings -- Best regards, Bulatmailto:bulat.zigans...@gmail.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Wondering if this could be done.
On 22 November 2010 07:48, Magicloud Magiclouds magicloud.magiclo...@gmail.com mailto:magicloud.magiclo...@gmail.com wrote: Hi, For example, I have a data A defined. Then I want to add (+) and (-) operators to it, as a sugar (compared to addA/minusA). But * or other stuff defined in class Num is meanless to A. So I just do: (+) :: A - A - A (+) a b = A (elem1 a + elem1 b) (elem2 a + elem2 b) -- I got errors here, for the (+) is ambiguous. So, just wondering, does this way work in Haskell? (*) and (+) are in separate type classes in Numeric-Prelude. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Reduceron: reduced to numbers.
Serguey Zefirov schrieb: Of course, Reduceron in ASIC will require some cache memory, some controllers, etc. So it won't be that small, like 230K transistors. But, mzke it 2.3M transistors and it still be 2 orders of magnitude less than Core2 Duo... ;) Cool! Do you have plans how it can be used eventually? As expansion card? As main processor? How to compile Haskell to Reduceron code? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Wondering if this could be done.
On Mon, 2010-11-22 at 14:48 +0800, Magicloud Magiclouds wrote: (+) :: A - A - A (+) a b = A (elem1 a + elem1 b) (elem2 a + elem2 b) -- I got errors here, for the (+) is ambiguous. That's because (+) is implicitly imported from the Prelude. If you import Prelude hiding ((+)) the error disappears. Sebastian ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Safer common subexpression elimination
Joachim Breitner schrieb: Hi, although semantically it could, ghc does not do common subexpression elimination (CSE), at least not in every case. The canonical example where it would be bad is the function (with div to avoid numerical casting): avg :: [Int] - Int avg n = (sum [0..n] `div` length [0..n]) The reason why [0..n] is not shared is because then it would be kept in memory completely after the evaluation of sum, because length will still need it, possibly overflowing the memory. In the non-shared form, though, the garbage collector can clean up directly behind sum and length, and the program runs in constant space. Note that the shared expression would be very large compared to the thunks. Now consider the program: avg' :: [Int] - (Int, Int) avg' n = (sum [0..n] `div` length [0..n], length [0..n]) It think this is not typecorrect, since 'n' denotes a list and is used as upper bound in [0..n]. Should it be avg' ns = (sum ns `div` length ns, length ns) ? I’d say that CSE to avg n = (sum [0..n] `div` l, l) where l = length [0..n] is safe, because the shared expression (an Int) is smaller than the thunks and the compiler can tell. If this is meant to be avg n = (sum ns `div` l, l) where l = length ns according to my substitution above, then 'ns' still has to be shared and stored completely. I think the general problem is more complicated than common subexpression elimination, because lazy evaluation sometimes forces an inefficient order of computation. Other examples are viewR xs = (init xs, last xs) and an elegant Haskell implementation of the Unix command 'wc' like wc text = (length text, length (words text), length (lines text)) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Safer common subexpression elimination
Hello Henning, Am Samstag, den 04.12.2010, 12:41 +0100 schrieb Henning Thielemann: Joachim Breitner schrieb: Now consider the program: avg' :: [Int] - (Int, Int) avg' n = (sum [0..n] `div` length [0..n], length [0..n]) It think this is not typecorrect, since 'n' denotes a list and is used as upper bound in [0..n]. Should it be avg' ns = (sum ns `div` length ns, length ns) ? Thanks for noting. The type annotation is wrong. In your case (which I had first), ns is shared and thus would not allow for constant-space calculation of sum and length and would fail to demonstrate my point. I’d say that CSE to avg n = (sum [0..n] `div` l, l) where l = length [0..n] is safe, because the shared expression (an Int) is smaller than the thunks and the compiler can tell. If this is meant to be avg n = (sum ns `div` l, l) where l = length ns according to my substitution above, then 'ns' still has to be shared and stored completely. Right, sorry for the confusion by the wrong type. Greetings, Joachim -- Joachim Breitner e-Mail: m...@joachim-breitner.de Homepage: http://www.joachim-breitner.de ICQ#: 74513189 Jabber-ID: nome...@joachim-breitner.de signature.asc Description: This is a digitally signed message part ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Reduceron: reduced to numbers.
2010/12/4 Henning Thielemann schlepp...@henning-thielemann.de: Serguey Zefirov schrieb: Of course, Reduceron in ASIC will require some cache memory, some controllers, etc. So it won't be that small, like 230K transistors. But, mzke it 2.3M transistors and it still be 2 orders of magnitude less than Core2 Duo... ;) Cool! Do you have plans how it can be used eventually? As expansion card? As main processor? How to compile Haskell to Reduceron code? I don't know answers to most of your questions. But colleague of mine said that reduceron could be programmed into FPGA part of upcoming Atom E600 - the one with Altera FPGA nearby. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] OverloadedStrings mixed with type classes leads to boilerplate type signatures
Hi,
I'm trying to generalize my string substitution library
(http://hackage.haskell.org/package/template) to allow users to
provide different kinds of key/value mappings (e.g. functions and
association lists) for filling in the placeholders in a template. Here
are two examples I'd like to work:
ghci :set -XOverloadedStrings
ghci $name ate a banana. % [(name, Johan)]
Johan ate a banana.
ghci $name ate a banana. % (\v - if v == name then Johan
else error KeyError)
Johan ate a banana.
At the moment the context (i.e. the second argument to %) is always a function
type Context = T.Text - T.Text
I would like to generalize that to
class Context a where
lookup :: a - T.Text - T.Text
Different key/value mappings fulfill different use cases:
* Association lists have a small syntactic overhead, great for
one-off string substitution.
* Functions are flexible, allowing for arbitrary complex lookup
logic, but are syntactically heavy (in this case.)
Here's the gist of my implementation:
{-# LANGUAGE FlexibleInstances #-}
module Template where
import Data.Maybe (fromMaybe)
import qualified Data.Text as T
import qualified Data.Text.Lazy as LT
import Prelude as P
class Context a where
lookup :: a - T.Text - T.Text
instance Context (T.Text - T.Text) where
lookup f = f
instance Context [(T.Text, T.Text)] where
lookup xs k = fromMaybe (error $ KeyError: ++ show k) (P.lookup k xs)
-- | Perform string substitution. Example:
--
-- $foo % [(foo :: T.Text, bar :: T.Text)]
(%) :: Context c = T.Text - c - LT.Text
(%) = undefined
The problem is that the compiler is not able to deduce that string
literals should have type 'Text' when used in 'Context's. For example
ghci :t $foo % [(foo, bar)]
interactive:1:8:
No instance for (Context [(a, a1)])
arising from a use of `%'
Possible fix: add an instance declaration for (Context [(a, a1)])
In the expression: $foo % [(foo, bar)]
This forces the user to provide explicit type signatures, which makes
the construct more heavy weight and defeats the whole purpose of
introducing the 'Context' class:
ghci :t $foo % [(foo :: T.Text, bar :: T.Text)]
$foo % [(foo :: T.Text, bar :: T.Text)] :: LT.Text
Is there any way to make the syntactically short `$foo % [(foo,
bar)]` work but still keep the 'Context' class?
Johan
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[Haskell-cafe] Hackage down?
http://downforeveryoneorjustme.com/http://hackage.haskell.org -- Ozgur Akgun ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Hackage down?
On Sat, Dec 04, 2010 at 02:01:44PM +, Ozgur Akgun wrote:
http://downforeveryoneorjustme.com/http://hackage.haskell.org
Apparently {darcs,hackage}.haskell.org is out for the day -- announced
on Reddit but not here.
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[Haskell-cafe] Offer to mirror Hackage
With Hackage down, now seemed like a good time to push this issue again. It's such an important site to us that it's really rather a shame there are no mirrors of it. I have a personal-and-business server in a data center in Newark, with a fair chunk of bandwidth, which I'd like to offer for a permanent mirror. Is there interest in this? Who do I need to talk to for it to happen? Strategy-wise, I think the best approach is round-robin DNS, since that's transparent to the end user - everything would still appear at the URL it's at now, but behind-the-scenes magic would let things keep working when one or the other site is down. I haven't personally set up such a system before but I'm willing to take on the burden of figuring it out. So I have a better idea of what I'm signing up for, can anyone tell me how much disk space and how much bandwidth per month Hackage uses? I have a fair chunk of both, as I say, but I'd like to know in advance to ensure that things go smoothly. As for what I'd want in return for this, really nothing. I wouldn't say no to an unobtrusive mention somewhere on the site, but I'd be happy just knowing I'd given something back to the Haskell community, which has given a lot to me. -- Dan Knapp An infallible method of conciliating a tiger is to allow oneself to be devoured. (Konrad Adenauer) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Offer to mirror Hackage
I am no decision maker regarding Hackage, but I would like to echo my support for this offer. Hackage is a vital part of my workflow, and I'm sure I'm not the only one. Its importance to the Haskell community has grown quickly and is continuing to do so. Each time it goes down, the impact is larger than before. We should have a mirror in place for situations like these. - Jake ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] getErrorStatus in HXT
Hi Tobias, I have some problems with the error processing in HXT. Here is a trivial example: e - runX (transformDoc [] someRules src dst) transformDoc cfg rules src dst = configSysVars cfg readDocument [] src rules -- some transformations writeDocument [] dst getErrStatus I would expect e to contain an error value = c_err for the case where any of the processing steps in transformDoc fails. But it does not, even with an io error on writeDocument. I guess I misunderstand getErrStatus in some way. Any idea? no, you've got it as it should be. This is an error introduced hxt-9.0 when changing the internals of the global hxt state. I've removed that bug in the head of the development version. If there's no time for you to wait until hxt-9.1, the dev. version is available from github at https://github.com/UweSchmidt/hxt;. Sorry for that inconvenience, Uwe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Hackage down?
Thanks, Ross.
Here's a Reddit post:
http://www.reddit.com/r/haskell/comments/efw38/reminder_hackagehaskellorg_outage_tomorrow_due_to/
Antoine
On Sat, Dec 4, 2010 at 8:20 AM, Ross Paterson r...@soi.city.ac.uk wrote:
On Sat, Dec 04, 2010 at 02:01:44PM +, Ozgur Akgun wrote:
http://downforeveryoneorjustme.com/http://hackage.haskell.org
Apparently {darcs,hackage}.haskell.org is out for the day -- announced
on Reddit but not here.
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Re: [Haskell-cafe] getErrorStatus in HXT
Hi Uwe, thanks a lot for the clarification! Indeed, I was a bit confused since all other concepts in HXT are straight forward and easy to grasp. When is the release of hxt-9.1 on hackage expected? On 12/04/2010 05:49 PM, Uwe Schmidt wrote: Hi Tobias, I have some problems with the error processing in HXT. Here is a trivial example: e- runX (transformDoc [] someRules src dst) transformDoc cfg rules src dst = configSysVars cfg readDocument [] src rules -- some transformations writeDocument [] dst getErrStatus I would expect e to contain an error value= c_err for the case where any of the processing steps in transformDoc fails. But it does not, even with an io error on writeDocument. I guess I misunderstand getErrStatus in some way. Any idea? no, you've got it as it should be. This is an error introduced hxt-9.0 when changing the internals of the global hxt state. I've removed that bug in the head of the development version. If there's no time for you to wait until hxt-9.1, the dev. version is available from github at https://github.com/UweSchmidt/hxt;. Sorry for that inconvenience, Uwe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Hackage down?
What the heck does a full torque of the electrical bus riser mean?
Don't get me wrong, it sounds badass.
-deech
On Sat, Dec 4, 2010 at 12:03 PM, Antoine Latter aslat...@gmail.com wrote:
Thanks, Ross.
Here's a Reddit post:
http://www.reddit.com/r/haskell/comments/efw38/reminder_hackagehaskellorg_outage_tomorrow_due_to/
Antoine
On Sat, Dec 4, 2010 at 8:20 AM, Ross Paterson r...@soi.city.ac.uk wrote:
On Sat, Dec 04, 2010 at 02:01:44PM +, Ozgur Akgun wrote:
http://downforeveryoneorjustme.com/http://hackage.haskell.org
Apparently {darcs,hackage}.haskell.org is out for the day -- announced
on Reddit but not here.
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Re: [Haskell-cafe] Offer to mirror Hackage
This is a very generous offer. However, I must say I like the following idea more: http://www.reddit.com/r/haskell/comments/efw38/reminder_hackagehaskellorg_outage_tomorrow_due_to/c17u7nk On 4 December 2010 16:31, Dan Knapp dan...@gmail.com wrote: With Hackage down, now seemed like a good time to push this issue again. It's such an important site to us that it's really rather a shame there are no mirrors of it. I have a personal-and-business server in a data center in Newark, with a fair chunk of bandwidth, which I'd like to offer for a permanent mirror. Is there interest in this? Who do I need to talk to for it to happen? Strategy-wise, I think the best approach is round-robin DNS, since that's transparent to the end user - everything would still appear at the URL it's at now, but behind-the-scenes magic would let things keep working when one or the other site is down. I haven't personally set up such a system before but I'm willing to take on the burden of figuring it out. So I have a better idea of what I'm signing up for, can anyone tell me how much disk space and how much bandwidth per month Hackage uses? I have a fair chunk of both, as I say, but I'd like to know in advance to ensure that things go smoothly. As for what I'd want in return for this, really nothing. I wouldn't say no to an unobtrusive mention somewhere on the site, but I'd be happy just knowing I'd given something back to the Haskell community, which has given a lot to me. -- Dan Knapp An infallible method of conciliating a tiger is to allow oneself to be devoured. (Konrad Adenauer) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Ozgur Akgun ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC 7.0.1 developer challenges
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 11/24/10 20:59 , John D. Ramsdell wrote: Due to a security concern, GHC 7.0.1 disables all runtime flags unless a new flag is provided during linking. Since limiting memory usage is so important, many developers will modify their cabal files to add the linker flag or prepare for complaints from users that the developer's program caused their machine to freeze and lose their work. We went over this some time back; the GHC runtime is wrong here, it should only disable flags when running with geteuid() == 0. Also, the current mechanism for specifying runtime flags at compile time is horridly ugly and this really needs to be fixed before any such runtime limitation is viable. I hope that will be fixed in a later point release. - -- brandon s. allbery [linux,solaris,freebsd,perl] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.10 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkz6i6gACgkQIn7hlCsL25VajgCeKqReTXt0JlQ90iTPtvU6VRXy 1PkAoJC83Glcy3jurrxH7eoiNGFZdazJ =Zi+B -END PGP SIGNATURE- ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC 7.0.1 developer challenges
Excerpts from Brandon S Allbery KF8NH's message of Sat Dec 04 13:42:48 -0500 2010: We went over this some time back; the GHC runtime is wrong here, it should only disable flags when running with geteuid() == 0. Also, the current mechanism for specifying runtime flags at compile time is horridly ugly and this really needs to be fixed before any such runtime limitation is viable. I hope that will be fixed in a later point release. There are many setuid binaries to non-root users, so getuid() != geteuid() would probably make more sense, though I'm not 100% it has all the correct security properties. Edward ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Offer to mirror Hackage
Ozgur Akgun ozgurak...@gmail.com wrote: This is a very generous offer. However, I must say I like the following idea more: http://www.reddit.com/r/haskell/comments/efw38/ reminder_hackagehaskellorg_outage_tomorrow_due_to/c17u7nk I'd support this, but I'm strongly in favor of the use of WePay.com over PayPal for collecting funds. The former's shady history is a matter of public record. Alternatively, I'd also be willing to throw some of my own bandwidth and disk space towards a mirror. -=rsw ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC 7.0.1 developer challenges
Edward Z. Yang ezy...@mit.edu wrote: There are many setuid binaries to non-root users, so getuid() != geteuid() would probably make more sense, though I'm not 100% it has all the correct security properties. Might as well throw in getegid() != getgid() for good measure. Another issue with this: in the next couple years it looks like Fedora and Ubuntu will both be going towards filesystem capabilities instead of suid. If access to +RTS is restricted for suid binaries, it should probably also be restricted for binaries with elevated capabilities. -=rsw ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Safer common subexpression elimination
Joachim Breitner schrieb: Am Samstag, den 04.12.2010, 12:41 +0100 schrieb Henning Thielemann: Joachim Breitner schrieb: Now consider the program: avg' :: [Int] - (Int, Int) avg' n = (sum [0..n] `div` length [0..n], length [0..n]) It think this is not typecorrect, since 'n' denotes a list and is used as upper bound in [0..n]. Should it be avg' ns = (sum ns `div` length ns, length ns) ? Thanks for noting. The type annotation is wrong. In your case (which I had first), ns is shared and thus would not allow for constant-space calculation of sum and length and would fail to demonstrate my point. I see. It may be that GHC actually eliminates common subexpression of primitive types. Its Core output will tell you. Nonetheless, maybe it is more sensible for a compiler not to answer the question whether a common subexpression should be shared or not, but it may try to evaluate the depending expressions in a way such that the shared data structure can be garbage collected as computation goes on. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Data.Typeable TypeRep Ord instance.
Why TypeRep does have equality and doesn't have ordering? It would be good to have that. Right now when I have to order two type representations I convert them to string and then compare. This is somewhat inefficient and not quite straightforward. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHC 7.0.1 developer challenges
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 12/4/10 14:35 , Riad S. Wahby wrote: Edward Z. Yang ezy...@mit.edu wrote: There are many setuid binaries to non-root users, so getuid() != geteuid() would probably make more sense, though I'm not 100% it has all the correct security properties. Might as well throw in getegid() != getgid() for good measure. Another issue with this: in the next couple years it looks like Fedora and Ubuntu will both be going towards filesystem capabilities instead of suid. If access to +RTS is restricted for suid binaries, it should probably also be restricted for binaries with elevated capabilities. Yes to both. And on Windows I wonder if it makes sense to try to detect that a program is running with restricted permissions (lack of membership in certain groups) and likewise restrict use of runtime options. (I don't think there's anything like setuid, though, and it probably makes no sense to try to detect that someone installed the program as a service running as LSA or used RunAs.) - -- brandon s. allbery [linux,solaris,freebsd,perl] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.10 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkz6xIQACgkQIn7hlCsL25XuiACfbUPTtk1Qkvo5fpWJzhX/WrbL A54An2CLYNa6Rza5KmswyrRJlKAb/w0G =X0nY -END PGP SIGNATURE- ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Data.Typeable TypeRep Ord instance.
Why should they? You can compare them in whatever way you like. And there isn't a natural/inherent sense of total order between types. On Sun, Dec 5, 2010 at 6:08 AM, Serguey Zefirov sergu...@gmail.com wrote: Why TypeRep does have equality and doesn't have ordering? It would be good to have that. Right now when I have to order two type representations I convert them to string and then compare. This is somewhat inefficient and not quite straightforward. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Tianyi Cui ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] the beginning of the end (was: Hackage down?)
On 10-12-04 01:03 PM, Antoine Latter wrote: Here's a Reddit post: http://www.reddit.com/r/haskell/comments/efw38/reminder_hackagehaskellorg_outage_tomorrow_due_to/ This is the second consecutive time a planned downtime is not announced on either mailing lists. This seems to me planned obsoletion of the mailing lists. http://article.gmane.org/gmane.comp.lang.haskell.cafe/82673 Was the planned obsoletion of the mailing lists also announced on reddit? Personally I refuse to use reddit and many web 2.0 things for both pragmatic (usability) and ideological reasons. The most important pragmatic reason for me is retarded or no attempt at mark-as-read and show-all-and-only-those-unread. For now, if a web 2.0 source I care enough about provides RSS, I make do with adding it to Google Reader, which provides mark-as-read and show-all-and-only-those-unread as perfectly as long-existing email programs. But it is always refreshing to see that our young ones are heading to a brave new world of synergy in which the only web 2.0 programmers who have heard of the discrete math idea of subset are the elite ones at Google. And to think that I once joked that in the future only math PhDs, and only some of them, know how to divide. http://groups.google.com/group/k12.chat.teacher/msg/62eccc5e1916a1da ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Data.Typeable TypeRep Ord instance.
2010/12/5 Tianyi Cui tianyi...@gmail.com:
Why should they? You can compare them in whatever way you like. And there
isn't a natural/inherent sense of total order between types.
I cannot compare then the way I'd like. ;)
Consider the following:
data BiMap a = BiMap {
values :: Map Int a
,indices :: Map a Int
}
It will serve well for Int's, Bool's and Expr's.
Then I decided to store typed Expr's, based on GADTs. Those Expr's
contains type indices and it would be natural to classify BiMaps by
their type indices and look up in there. If I require type indices to
be Typeable, all I need is ordering on TypeRep.
Also, I prototyped hypergraph library with hyperedges as types with
type family as HList of types denoting labels. There I needed ordering
on TypeRep too, again, for efficiency reasons.
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Re: [Haskell-cafe] the beginning of the end (was: Hackage down?)
trebla: On 10-12-04 01:03 PM, Antoine Latter wrote: Here's a Reddit post: http://www.reddit.com/r/haskell/comments/efw38/reminder_hackagehaskellorg_outage_tomorrow_due_to/ This is the second consecutive time a planned downtime is not announced on either mailing lists. This seems to me planned obsoletion of the mailing lists. http://article.gmane.org/gmane.comp.lang.haskell.cafe/82673 For now, if a web 2.0 source I care enough about provides RSS, I make do with adding it to Google Reader, which provides mark-as-read and show-all-and-only-those-unread as perfectly as long-existing email programs. You can get a feed of haskell.org announcements here: http://twitter.com/statuses/user_timeline/216043045.rss Particularly when the mailing lists are down (e.g. due to server migration), cloud-hosted services have proven invaluable for getting the word out. -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Offer to mirror Hackage
On 12/4/10 11:31 AM, Dan Knapp wrote: With Hackage down, now seemed like a good time to push this issue again. It's such an important site to us that it's really rather a shame there are no mirrors of it. I have a personal-and-business server in a data center in Newark, with a fair chunk of bandwidth, which I'd like to offer for a permanent mirror. Is there interest in this? Absolutely. Who do I need to talk to for it to happen? I'd guess that'd be the haskell.org steering committee: http://haskellorg.wordpress.com/2010/11/15/the-haskell-org-committee-has-formed/ -- Live well, ~wren ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Offer to mirror Hackage
On 12/4/10 2:21 PM, Riad S. Wahby wrote: Ozgur Akgunozgurak...@gmail.com wrote: This is a very generous offer. However, I must say I like the following idea more: http://www.reddit.com/r/haskell/comments/efw38/ reminder_hackagehaskellorg_outage_tomorrow_due_to/c17u7nk That sounds like a great idea. The 501(c)(3) I mean. The distributed hosting is nice too, though I'd like to see the 501(c)(3) formed before donating, just so we can get official reports and all that. But once that's up, I'm definitely willing to contribute. FWIW, I've been on the board of directors for a 501(c)(3), helped write their bylaws, and know a few people in the business (lawyers, etc). I'm willing to offer advice, effort, and references whenever the committee decides to do this. I'd support this, but I'm strongly in favor of the use of WePay.com over PayPal for collecting funds. The former's shady history is a matter of public record. Semantic Parse Fail: did you mean the latter or strongly opposed to? Alternatively, I'd also be willing to throw some of my own bandwidth and disk space towards a mirror. For a scalable solution I think we should be aiming for both (1) a distributed central server, and (2) mirrors around the globe. The former gives reliability to the main site, but the latter help for locality and loadbalancing as well as failover. -- Live well, ~wren ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Offer to mirror Hackage
wren ng thornton w...@freegeek.org wrote: Semantic Parse Fail: did you mean the latter or strongly opposed to? s/former/latter/ :) -=rsw ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Offer to mirror Hackage
Why is there even any consideration of some committee if someone wants to mirror the Hackage site? Why not mirror the site? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
