- Haskell-prime - Haskell.org

defaults
by Malcolm Wallace 16 Jan '07

16 Jan '07

Prompted by recent discussion on the Hat mailing list about the problems of type-defaulting, I have added two new proposals for this issue to the Haskell-prime wiki at: http://hackage.haskell.org/trac/haskell-prime/wiki/Defaulting The main new proposal is a different way of specifying defaults, which includes the name of the class being defaulted (thus allowing user-defined classes to play this game), but unlike the original proposal, permits only one type to be specified per class. The rules are therefore also simpler, whilst still (I believe) capturing the useful cases. A secondary proposal is to generalise defaults from having module-local scope, to global scope. This would allow library authors to capture the intended behaviour of their own classes and types, without bothering the library users. (Also, whilst removing module-local redefinition of defaults, the proposal would instead permit function-local re-definition.) I am less convinced of the need for this proposal, but in the spirit of exploring the design space, I thought it worth bringing up. Regards, Malcolm

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pattern guards: recent changes to draft haskell prime report
by isaac jones 15 Jan '07

15 Jan '07

Greetings! We've been working to add pattern guards to the Haskell' report, and doing some cleanup work on the repository. Not all of the emails are making it to the list, sadly, but here's a list of recent changes from the report. You can view the report itself here (I couldn't think of a good place to put it): http://hackage.haskell.org/~ijones/haskell-prime-report/report/haskell98-re… peace, isaac Fri Jan 12 16:32:28 PST 2007 iavor.diatchki(a)gmail.com * moved rules for guards in a separate figure because the old figure didn't fit on a page Fri Jan 12 16:21:46 PST 2007 iavor.diatchki(a)gmail.com * fixed rule (g) of pattern semantics to avoid duplicating the evaluation of e' Fri Jan 12 16:13:50 PST 2007 iavor.diatchki(a)gmail.com * added rules for pattern guards to the formal semantics of case Fri Jan 12 14:53:30 PST 2007 iavor.diatchki(a)gmail.com * gneralized function bindings to support pattern guards, not just boolean guards Thu Jan 11 16:59:30 PST 2007 ijones(a)syntaxpolice.org * reworking the informal explanation of pattern gaurds Modified the syntax again to talk about "guards" (which are pattern guards, boolean guards, and let expressions) . Moved the "Pattern guards" section I created before into the Case Expressions section. Thu Jan 11 15:51:14 PST 2007 ijones(a)syntaxpolice.org * update pattern binding translation for pattern guards (with Iavor's help!) Mon Jan 8 10:21:14 PST 2007 Andres Loeh <mail(a)andres-loeh.de> * turn macro into function -- makes it work with newer flex versions Mon Jan 8 09:50:40 PST 2007 Andres Loeh <mail(a)andres-loeh.de> * don't include extension in \includegraphics (to make compatible with pdflatex) Mon Jan 8 09:20:29 PST 2007 Andres Loeh <mail(a)andres-loeh.de> * typo: change \r to \tr

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patch applied (haskell-prime-report): Update lots of references to H' 98 -> Prime, especially in build system.
by Malcolm Wallace 15 Jan '07

15 Jan '07

Mon Jan 15 06:47:52 PST 2007 Malcolm.Wallace(a)cs.york.ac.uk * Update lots of references to H'98 -> Prime, especially in build system. I have taken the liberty of rejigging the build system somewhat, so that we can auto-generate the PDF/HTML version of the Language Report every time a patch is checked into darcs. M ./Makefile -3 +8 M ./README -12 +18 M ./report/Makefile -10 +11 M ./report/README -2 +2 R ./report/h98-revised.html R ./report/h98.gif A ./report/haskell-prime-draft.html R ./report/haskell98-bugs.html R ./report/haskell98-revised-bugs.html A ./report/hprime.png A ./report/hprime.ppt M ./report/html.config -6 +6 M ./report/index.html -7 +6 M ./tools/index.hs -1 +1

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patch applied (haskell-prime-report): some notes on how to build it.
by Simon Marlow 14 Jan '07

14 Jan '07

Mon Jan 8 03:11:48 PST 2007 Simon Marlow <simonmar(a)microsoft.com> * some notes on how to build it. M ./README -6 +26

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patch applied (haskell-prime-report): reworking the informal explanation of pattern gaurds
by Isaac Jones 12 Jan '07

12 Jan '07

Thu Jan 11 16:59:30 PST 2007 ijones(a)syntaxpolice.org * reworking the informal explanation of pattern gaurds Modified the syntax again to talk about "guards" (which are pattern guards, boolean guards, and let expressions) . Moved the "Pattern guards" section I created before into the Case Expressions section. M ./report/decls.verb -3 +4 M ./report/exps.verb -63 +71

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patch applied (haskell-prime-report): update pattern binding translation for pattern guards (with Iavor' s help!)
by Isaac Jones 12 Jan '07

12 Jan '07

Thu Jan 11 15:51:14 PST 2007 ijones(a)syntaxpolice.org * update pattern binding translation for pattern guards (with Iavor's help!) M ./report/decls.verb -7 +9

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patch applied (haskell-prime-report): Change front matter to say " Haskell Prime" rather than " Haskell 98" .
by Malcolm Wallace 08 Jan '07

08 Jan '07

Mon Jan 8 07:06:32 PST 2007 Malcolm.Wallace(a)cs.york.ac.uk * Change front matter to say "Haskell Prime" rather than "Haskell 98". M ./report/haskell.verb -5 +6 M ./report/intro.verb -1 +1 M ./report/preface-jfp.verb -53 +68

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patch applied (haskell-prime-report): create $(RELEASE_DIR) if necessary
by Simon Marlow 08 Jan '07

08 Jan '07

Mon Jan 8 03:01:50 PST 2007 Simon Marlow <simonmar(a)microsoft.com> * create $(RELEASE_DIR) if necessary M ./report/Makefile +1

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patch applied (haskell-prime-report): add clean target
by Simon Marlow 08 Jan '07

08 Jan '07

Mon Jan 8 02:59:08 PST 2007 Simon Marlow <simonmar(a)microsoft.com> * add clean target M ./tools/Makefile +4

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patch applied (haskell-prime-report): very rough draft of informal pattern-guard (qualifiers) explanations
by Isaac Jones 08 Jan '07

08 Jan '07

Sun Jan 7 19:26:27 PST 2007 ijones(a)syntaxpolice.org * very rough draft of informal pattern-guard (qualifiers) explanations This is a very rough draft in order to get some discussion going, and does not touch the semantic explanations, which will still need to be done. M ./report/exps.verb -48 +63

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