December 2006 - Libraries

proposal: add 'unsafeCoerce'
by Malcolm Wallace 02 Apr '07

02 Apr '07

Currently, all implementations provide either the 'unsafeCoerce' or 'unsafeCoerce#' functions, but they live in implementation-specific locations. This proposal is to adopt the Haskell'98-compatible name 'unsafeCoerce', and to add it to the standard base library package. Suggested location: Data.Function.Unsafe? http://hackage.haskell.org/trac/ghc/ticket/994 Regards, Malcolm

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hs-plugins runtime error with GHC 6.6: index out of range
by Cyril Schmidt 15 Jan '07

15 Jan '07

After upgrading from GHC 6.4.2 to GHC 6.6 and rebuilding hs-plugins package, I noticed that hs-plugins does not work anymore. When I try to load a plugin, I get an "Index out of range" error. For example, when I compile the hs-plugins\testsuite\make\simple example and run the executable, the error message is a.out: Ix{Int}.index: Index (65536) out of range ((0,11)) Other tests give similar results; the values of the index and the range vary. Does anybody know what is wrong here? I use hs-plugins-1.0-rc0 and GHC 6.6 on Windows (hs-plugins worked fine with GHC 6.4.2). Cheers, Cyril

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haddock & web-friendly library links?
by Conal Elliott 10 Jan '07

10 Jan '07

My library uses others (including base & wxHaskell), and so references to types & identifiers from those libraries show up in my Haddock docs. When I put the docs on the web, the links are bogus. How can I get those links to be web-accessible versions instead of my local versions? Similarly, I want to package up my library so that others can build on top of it and have their published haddock documentation contain web-accessible pointers to my doc. Have these issues been thought through? Thanks, - Conal ---------- Forwarded message ---------- From: Doaitse Swierstra <doaitse(a)cs.uu.nl> Date: Dec 13, 2006 2:26 AM Subject: Re: [Haskell] ANNOUNCE: Phooey -- a Functional UI library for Haskell To: Conal Elliott <conal(a)conal.net> Cc: Doaitse Swierstra <doaitse(a)cs.uu.nl> Hi Conal, when clicking on "Arrow" in your haddock documentation at: http://darcs.haskell.org/packages/phooey/doc/Graphics-UI-Phooey.html#t%3AUI my browser is directed to: c:/ghc/ghc-6.6/doc/html/libraries/base/Control-Arrow.html#t%3AArrow which does not seem good to me, Best, Doaitse

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RE: Idea to allow people to comment on Haskell docs
by Simon Peyton-Jones 09 Jan '07

09 Jan '07

| I've had a go at patching Haddock to put a link on the page for each | module. It's controlled by an optional --wiki=URL flag. | | As an example, I used this with the (devel version of the) Gtk2Hs docs: | | http://haskell.org/gtk2hs/docs/devel/ | | For example this page: | | http://haskell.org/gtk2hs/docs/devel/Graphics-Rendering-Cairo-SVG.html It looks great! But I'd never have found the link if you hadn't pointed me at it. Rather than "Wiki" say "User comments". And I think the per-entry [User comment] link is essential. Typically people are going to be looking at a particular thing. For example, here http://haskell.org/gtk2hs/docs/devel/Graphics-Rendering-Cairo-SVG.html#v %3AsvgRenderFromString is where I'd look for the link for svgRenderFromString. Does MediaWiki support anchors in the middle of a page? That's essential here -- we want one Wiki page for one Haddock page. On a closely related matter, Benjamin Pierce told me how often he wished that there was a link from the Haddock documentation to the source code for a function. Especially for Prelude functions, he's dead right. So another really useful Haddock enhancement would be the ability to add links to the source code from the Haddock docs --- again on a per-function basis. Do you feel like adding that too? Where should the code live? I'd suggest snap-shoting it at the moment that the Haddock docs are generated, and putting the files with the Haddock docs. Simon

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Proposal: Add parsing (and some other changes) to the time package
by Bjorn Bringert 21 Dec '06

21 Dec '06

I propose adding parsing to the time package. I also propose some minor other changes and bugfixes. I have implemented the changes that I consider reasonably clear-cut. The rest I will implement after community input. All already implemented changes are available from: http://www.cs.chalmers.se/~bringert/darcs/time/ All objections, comments, etc. are welcome. I especially would like feedback on the unimplemented enhancements, and any objections to the already implemented ones. I have created ticket #1007 to track this proposal: http:// hackage.haskell.org/trac/ghc/ticket/1007 Proposal: == Executive summary == (see below for more details). === Implemented enhancements === * Add time parsing to the time package, including Read instances. * Add fromMondayStartWeek and fromSundayStartWeek. * Add secondsToDiffTime and picosecondsToDiffTime. === Unimplemented enhancements === * Change %S to: the number of whole seconds. * Add %q: the number of picoseconds (including trailing zeroes). * Add %Q: decimal point and second decimals, without trailing zeros. * Add %f: The century part of the week date year. * Change %Z to produce the time zone offset if the time zone name is "". * Add Eq and Ord instances for ZonedTime? * Add Typeable and Data instances for all the time package types. === Fixed bugs === * formatTime "%c" did not include the time zone when applied to ZonedTime or UTCTime. * s/propleptic/proleptic/ in some Haddock comments. * formatTime documentation of range of %U and %W was wrong, should include 00. * The showWeekDate Haddock comment was missing the example. * The taiEpoch Haddock comment was missing the epoch time. === Unfixed bugs === * Haddock comments for toJulianYearAndDay and isJulianLeapYear talk about the Gregorian calendar. == Details == === Implemented enhancements === * Add time parsing to the time package. Rationale: The old System.Time has had a TODO "* add functions to parse strings to `CalendarTime' (some day...)" for a long time. The question about date parsing comes up once in a while on the mailing lists (e.g. http://comments.gmane.org/gmane.comp.lang.haskell.cafe/16438) * Add fromMondayStartWeek and fromSundayStartWeek to Data.Time.Calendar.OrdinalDate. Rationale: I can't find any duals of mondayStartWeek and sundayStartWeek. They are useful when implementing parsing for %W and %U. * Add secondsToDiffTime and picosecondsToDiffTime. Rationale: As has come up on haskell-cafe (http://comments.gmane.org/gmane.comp.lang.haskell.cafe/15653) it takes a while to figure out how to make DiffTime values. secondsToDiffTime is not that important since it is just another name for fromInteger, but I suspect that it would be used a lot. Using fromRational to create a DiffTime from a number of picoseconds is a bit of a hassle, so having a picosecondsToDiffTime would be useful. === Unimplemented enhancements === * formatTime: Change %S to: the number of whole seconds. * formatTime: Add %q: the number of picoseconds (including trailing zeroes). * formatTime: Add %Q: decimal point and second decimals, without trailing zeros. If the number of picoseconds is zero, nothing is produced (not even the decimal point). Rationale: Currently %S includes decimals if there are any. This is different from strftime, and there is no format specifier for just the integer part of the seconds. It would be nice to have such a specifier to implement many standard date formats (e.g. RFC 822). Also a specifier for second decimals would also help when using %s. Currently there is no reasonable way to get more than integer second precision with since-epoch timestamps. Thus the current %S would be equivalent to %S%Q under this proposal. * Add %f: The century part of the week date year. Rationale: There is a %g specifier for the last two digits of the week date year, but no specifier for the century. %C cannot be used, since the normal century and the week date century can differ: {{{ > formatTime defaultTimeLocale "%Y %G" (fromGregorian 2000 1 1) "2000 1999" }}} * Change %Z to produce the time zone offset if the time zone name is "". Rationale: Without this, if you format a ZonedTime which contains an unnamed timezone, %Z produces the empty string. This is invalid in many formats. It would be better to output the offset when there is no timezone name. * Add Eq and Ord instances for ZonedTime? Rationale: It's useful at least for the QuickCheck properties, but probably also elsewhere. There are lots of standard functions that want Eq and Ord. Problems: Should ZonedTimes be converted to UTC and compared, or should times in different timezones never be equal? I would argue for the latter, but I suspect that this problem is the reason why it never got included in the first place. Interestingly, there is a derived instance of Eq for TimeZone, which means that timezones with the same offset but different names are considered different. Following this logic, I think that ZonedTimes with different timezones should also be different. This should be noted in the documentation. * Add Typeable and Data instances for all the time package types. Rationale: It's useful and doesn't hurt anyone. === Fixed bugs === * formatTime "%c" does not include the time zone even when applied to ZonedTime or UTCTime, since "%c" is handled by the FormatTime LocalTime instance: {{{ > fmap (formatTime System.Locale.defaultTimeLocale "%c") getZonedTime "Sat Nov 11 19:12:45.395568 2006" > fmap (formatTime System.Locale.defaultTimeLocale "%c") getCurrentTime "Sat Nov 11 18:13:52.010944 2006" }}} * s/propleptic/proleptic/ in Data/Time/Calendar/JulianYearDay.hs and Data/Time/Calendar/OrdinalDate.hs * formatTime documentation of range of %U and %W was wrong, should include 00. * The showWeekDate haddock comment is: "show in ISO 8601 Week Date format as yyyy-Www-dd (e.g." * The taiEpoch haddock comment is just "The epoch of TAI, which is" === Unfixed bugs === * The haddock comments for toJulianYearAndDay and isJulianLeapYear in Data.Time.Calendar.JulianYearDay talk about the proleptic Gregorian calendar. This looks like a copy-and-paste problem. What is the calendar called? Proleptic Julian? /Björn Bringert

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Re: Control.Monad.Error documentation
by Andriy Palamarchuk 21 Dec '06

21 Dec '06

Just updated the source and Haddock output in the proposal: http://hackage.haskell.org/trac/ghc/ticket/1059 Haddock output: http://hackage.haskell.org/trac/ghc/attachment/ticket/1059/Control-Monad-Er… Changes: 1) Moved comments: ********************************* Rendered by Michael Weber <mailto:michael.weber@post.rwth-aachen.de>, inspired by the Haskell Monad Template Library from Andy Gill (<http://www.cse.ogi.edu/~andy/>) ********************************* outside of haddock documentation. 2) Created separate titles for both examples. 3) Replaced an example for custom error. Please review. Andriy __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Haddock plan -- syntactic extensions?
by Conal Elliott 20 Dec '06

20 Dec '06

I'd like to know what's realistic to expect with Haddock and GHC's language extensions in the near future, particularly arrow notation and GADTs. So far, I've been able to avoid arrow notation, at some cost some obfuscation, but I don't know how to avoid exposing Haddock to my GADTs. Cheers, - Conal

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Re: Control.Monad.Identity documentation
by Andriy Palamarchuk 19 Dec '06

19 Dec '06

Just to sum it up - there are no questions about this submission. It is ready for committing. Andriy ----- Original Message ---- From: Andriy Palamarchuk <apa3a(a)yahoo.com> To: libraries(a)haskell.org Sent: Monday, December 18, 2006 7:54:35 PM Subject: Re: Control.Monad.Identity documentation The deadline of the documentation proposal is up. There were no comments, so I assume everything is Ok. Can somebody commit the change? The patch is attached to the proposal: http://hackage.haskell.org/trac/ghc/ticket/1039 Thanks, Andriy __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com _______________________________________________ Libraries mailing list Libraries(a)haskell.org http://www.haskell.org/mailman/listinfo/libraries __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Re: Control.Monad.Error documentation
by Andriy Palamarchuk 19 Dec '06

19 Dec '06

----- Original Message ---- From: Neil Mitchell <ndmitchell(a)gmail.com> > "Rendered by Michael Weber mailto:michael.weber@post.rwth-aachen.de, > inspired by the Haskell Monad Template Library from Andy Gill > (http://www.cse.ogi.edu/~andy/)"; > > I can see the use of linking to papers describing modules, or linking > to sources of information where further details can be found, but I > can't remember many other modules which just have links to the > authors? If author credit is needed, wouldn't the source code be a > better place to put it? Do you suggest to move this information to the source code comments, so they won't appear in Haddock output? I'm for it. Any objections? > The bit at the top of description seems useful. Great. I'll use same format for other monads. > The example seems awfully long. The documentation contains 2 examples - one about general use of Error, the second one is about ErrorT monad transformer. You are right, the first example seems too long as for library documentation. Neil, you are not in general against examples in the library documentation, right? What do you think if I replace the first example with more cut-and-dry one, similiar to the ErrorT example? Andriy __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Re: Control.Monad.Identity documentation
by Andriy Palamarchuk 19 Dec '06

19 Dec '06

----- Original Message ---- From: Neil Mitchell <ndmitchell(a)gmail.com> > I know the deadline is up, but... No problem. Deadline is just another nudge to start a discussion :-) > "Rendered by Michael Weber mailto:michael.weber@post.rwth-aachen.de, > inspired by the Haskell Monad Template Library from Andy Gill > (http://www.cse.ogi.edu/~andy/)"; > > I can see the use of linking to papers describing modules, or linking > to sources of information where further details can be found, but I > can't remember many other modules which just have links to the > authors? If author credit is needed, wouldn't the source code be a > better place to put it? Well, this message was about all the documentation for most of the modules in Control.Monad packages. I just left it in place. Do you suggest to move this notice to non-haddock comments? I'm for it. > The bit at the top of description seems useful. Great. I'll include these descriptions for other monads too. > The example seems > awfully long. How about putting the example on a wiki, and then having > a link to say where further details and an example can be found? The Identity documentation does not have any examples :-) I assume this comment about the Error module documentation. I'll respond to you in that thread. Andriy __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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