Re: Second draft of the Haskell 2010 report available
Simon Marlow schrieb: If we changed patterns in the same way as you suggest for expressions above, then this would become clearer, right? By this change you would loose the important restriction that - is only legal to denote negated (integer or float) constants, which would then move from the grammar to the informal description. Any choice is fine. Christian ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
Re: Second draft of the Haskell 2010 report available
On 06/07/2010 13:17, Christian Maeder wrote: http://www.haskell.org/~simonmar/haskell-2010-draft-report-2/haskellch3.html infixexp → lexp qop infixexp (infix operator application) | - infixexp(prefix negation) | lexp This grammar rule describes a right associative nesting of (any) infix operators qop and prefix negation as binding weaker than any infix. Thus a parser would create from - 1 /= 1 a the tree - (1 /= (1 a)). The grammar is non-ambiguous and all you have to do is flatten the result to apply fixity resolution. I don't really see how generalising the grammar would help - the tree still has to be flattened to apply fixity resolution, and the parser would have to make an arbitrary choice from one of the possible parses. Or perhaps I'm missing something here? Cheers, Simon Would it not be better to give an ambiguous grammar and leave it to the infix resolution algorithm to allow only the intended trees, rather than letting the infix resolution algorithm correct a wrong tree? My suggestion would be to change the rule to: infixexp → infixexp qop infixexp (infix operator application) | - infixexp(prefix negation) | lexp thus only replacing the first lexp by infixexp. Cheers Christian ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
Re: Second draft of the Haskell 2010 report available
Simon Marlow schrieb: prefix negation should move to lexp to be consistent with lpat prefix negation should not move to lexp, because this would rule out - 1 ^ 2 as negated infix expression - (1 ^ 2), whereas a negated infix pattern is impossible. Unary minus is no constructor and cannot be defined. The latter should be (or is already?) mentioned somewhere. You could move prefix negation to lexp, if you allow the fixity resolution to construct negated infix expression that are not covered by the grammar (as currently happens anyway). Moving prefix negation from lpat to pat to be consistent with infixexp would be overkill, though. Christian ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
Re: Second draft of the Haskell 2010 report available
http://www.haskell.org/~simonmar/haskell-2010-draft-report-2/haskellch3.html infixexp → lexp qop infixexp (infix operator application) | - infixexp(prefix negation) | lexp This grammar rule describes a right associative nesting of (any) infix operators qop and prefix negation as binding weaker than any infix. Thus a parser would create from - 1 /= 1 a the tree - (1 /= (1 a)). Would it not be better to give an ambiguous grammar and leave it to the infix resolution algorithm to allow only the intended trees, rather than letting the infix resolution algorithm correct a wrong tree? My suggestion would be to change the rule to: infixexp → infixexp qop infixexp (infix operator application) | - infixexp(prefix negation) | lexp thus only replacing the first lexp by infixexp. Cheers Christian ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
Re: Second draft of the Haskell 2010 report available
On 16:01 Tue 29 Jun , Simon Marlow wrote: Comments on the draft report are welcome, before I finalise this and sign off on Haskell 2010. Part II, The Haskell 2010 Libraries, appears to be completely missing the Numeric module. -- Nick Bowler, Elliptic Technologies (http://www.elliptictech.com/) ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
Re: Second draft of the Haskell 2010 report available
On 29/06/2010 16:38, malcolm.wallace wrote: In Foreign.C.Error, the table of values of errno causes an unfortunate page break, and it overflows the fresh page as well. (As in, some values are invisible beyond the bottom of the page, rather than flowing onto the next.) Well spotted, thanks. Now fixed. Cheers, Simon ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
Re: Second draft of the Haskell 2010 report available
On Tue, Jun 29, 2010 at 04:01:54PM +0100, Simon Marlow wrote: The second draft of the Haskell 2010 report is now available in PDF and HTML formats (the PDF looks a lot nicer): http://www.haskell.org/~simonmar/haskell-2010-draft-report-2.pdf http://www.haskell.org/~simonmar/haskell-2010-draft-report-2/haskell.html Great work! I noticed a few things as I skimmed through it: p12(x) It too is intended to be a - It too was intended to be a p40(24) In local bindings are of the form let decls. there is a lot more white space between let and decls than there is in the BNF on the previous page p60(44) There are some odd-looking spaces before closing parentheses in the first paragraph. p62(46) Ix - Data.Ix (3 times) p79(63) Maybe - Data.Maybe p82(66) List - Data.List p121(105) Char, Monad, IO, and Numeric - Data.Char, Control.Monad, System.IO and Numeric p121(105) List - Data.List p122(106) Ratio - Data.Ratio p133(117) Char - Data.Char p139(123) Char - Data.Char p171(155) module provide the - module provides the p171(155) This is a bit klunky, talking about Control.Monad providing things that are actually defined in the Prelude. The The instances of Functor [...] defined in the Prelude is odd if you don't realise that. p172(156) Do you mean to have these instances?: instance Functor ReadP instance Monad P instance Monad ReadP p173(157) I don't think the report should refer to the mtl package. p173(157) Do you mean to have these instances?: instance MonadPlus P instance MonadPlus ReadP p175(159) Odd space after xm in [x1, x2, ..., xm ] p177(161) The module Data.Ix looks confusing; I assume it's being listed as an export? The paragraph above it doesn't look associated with it. p178(162) Talks about the difference between H98 and GHC p178(162) nonstrict - non-strict p179(163) Is strictness of the accumulating function actually relevant? p179(163) Talks about the difference between H98 and GHC p180(164) module Array - module Data.Array module Ix - module Data.Ix import Ix - import Data.Ix import List - import Data.List Something has gone wrong with 2 of the error calls. p186(170) Do you mean to have these instances?: instance Bits WordPtr instance Bits IntPtr p193(177) Do you mean to have these instances?: instance Typeable1 Complex instance (Data a, RealFloat a) = Data (Complex a) p194(178) module Complex - module Data.Complex p195(179) Bad indentation in the Fractional instance p197(181) see the section of the Haskell report dealing with arithmetic sequences) should be a link p201(185) three bullet points are indented more than the other one C20: There are a number of references to Data.List.foo rather than just foo, presumably from when the docs were in the Prelude rather than Data.List C20: In example, sometimes == is used but in other cases - is used p222(206) module Maybe - module Data.Maybe p226(210) module Ratio - module Data.Ratio p227(211) Bad indentation in Show instance p229(213) I don't understand One non-obvious consequence of this is that negate should not raise an error on negative arguments. p229(213) see the section of the Haskell report dealing with arithmetic sequences should be a link p235(219) Do you mean to have these instances?: instance Typeable ExitCode instance Exception ExitCode p236(220) sucessfully - successfully p244(228) Construct a Haskell 98 I/O error p245(229) additionlly - additionally p252(236) onwards: Lots of Typeable instances, and Typeable is also given in the list of classes in the 30.1.1, 30.1.2 and 30.1.3 opening paragraphs. p258(242) Talks about Data.Time p262(246) A Finalizer - A finalizer p262(246) like addForeignPtrFinalizerEnv - Like addForeignPtrFinalizerEnv p263(247) Mentions MVars p263(247) I don't think there should be GHC notes in the report p270(254) Delete This version traverses the array backwards using an accumulating parameter, which uses constant stack space. The previous version using mapM needed linear stack space. p276(260) marshall - marshal p278(262) Why is e.g. Char unqualified but Prelude.Double qualified? p285(269) Do you mean to have these instances?: instance Storable WordPtr instance Storable IntPtr p289(273) System.IO.openFile - openFile p291(275) System.IO.hFlush - hFlush (twice) p291(275) System.IO.hlookAhead - hlookAhead Thanks Ian ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
Re: Second draft of the Haskell 2010 report available
In Foreign.C.Error, the table of values of errno causes an unfortunate page break, and it overflows the fresh page as well. (As in, some values are invisible beyond the bottom of the page, rather than flowing onto the next.)Regards, Malcolm Comments on the draft report are welcome, before I finalise this and sign off on Haskell 2010. ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
Re: Second draft of the Haskell 2010 report available
I have now updated the libraries too. Rather than update all the library documentation manually, I (perhaps rashly) decided to make a LaTeX backend for Haddock instead, and generate the report automatically from the library source code. Perhaps I should have mentioned (before sending a formatting error report): thanks, this looks great! Auto-generation is definitely the way to go, and well worth the effort. I did notice one other small item, which is perhaps an infelicity rather than an error. The documentation for Data.List (20.10.1), the By operations, mentions It is often convenient to use these functions together with Data.Function.on. But sadly, Data.Function is not one of the libraries in the H'2010 set. I would personally be happy to add it, but perhaps it is too late, and we will need to wait for H'2011. Regards, Malcolm ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
