Re: [Haskell-cafe] The Layout Rule
Hi Michael, Michael D. Adams wrote: I am looking for background material on how GHC and other Haskell compilers implement the layout rule. In the context of our work on syntactic extensibility, we have implemented a declarative and extensible mechanism to specify and implement layout rules. A paper about the approach is currently under review, and a draft is available [1]. The implementation and evaluation data is available [2]. [1] http://sugarj.org/layout-parsing.pdf [2] http://github.com/seba--/layout-parsing We used our parser in the implementation of SugarHaskell, a syntactically extensible variant of Haskell. A paper about SugarHaskell is currently under review, and again, a draft is available [3]. The implementation can be installed as an Eclipse plugin from the SugarJ website [4]. A command-line version is forthcoming. [3] http://sugarj.org/sugarhaskell.pdf [4] http://sugarj.org/ Best Regards, Tillmann (on behalf of the SugarJ team) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] The Layout Rule
I am looking for background material on how GHC and other Haskell compilers implement the layout rule. Are there any papers, documentation, commentary, etc. that discus the actual implementation of this rule (even if only a paragraph or two)? I've already looked at the parsing code in GHC and UHC. Do any other Haskell compilers have interesting approaches for implementing the layout rule? I am writing a paper about a new formalism for indentation sensitive languages and I want to ensure I've covered the appropriate background material on existing implementations of the layout rule. Michael D. Adams mdmko...@gmail.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] New Layout Rule take 2
I have made some improvements to the algorithm, and I am happy to say that with some minor tweaks, it correctly lays out the programs in the nofib suite. the algorithm is not much more complicated than the current one in the report, but doesn't have the parse-error rule. it does require a single token of lookahead to look for an in. darcs get http://repetae.net/repos/getlaid/ I have also added a mode so it can work as a ghc preprocesor, allowing very easy testing. just compile with. ghc -pgmF /path/to/getlaid -F --make Main.hs and it will automatically process all your files. Now, it isn't perfect. I can construct pathological examples that the old rule would parse, but this one won't. however, if those examples don't actually occur in practice, then that is not so much an issue. my program doesn't handle many non-haskell 98 extensions, but can probably be easily modified to do so. John -- John Meacham - ⑆repetae.net⑆john⑈ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Layout rule (was Re: PrefixMap: code review request)
I wrote: I just installed Visual Haskell 0.1, and when I type in the editor, CPU usage rises to about 70% and there's a noticeable delay before each character appears on the screen. This is no longer happening, so I guess I ran afoul of a bug. -- Ben ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Layout rule (was Re: PrefixMap: code review request)
Duncan Coutts wrote: hIDE and Visual Haskell use the ghc lexer and get near-instantaneous syntax highlighting. Hmm... I just installed Visual Haskell 0.1, and when I type in the editor, CPU usage rises to about 70% and there's a noticeable delay before each character appears on the screen. This is a very short module (~100 lines) and a Pentium M 1600 CPU. Am I doing something wrong? -- Ben ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Layout rule (was Re: PrefixMap: code review request)
Benjamin Franksen wrote: TAB characters in program text should be forbidden by law. Well... they are quite useful for lining things up if you're using a proportional font, and I don't think proportionally-spaced code is a bad idea. I want them to be optional. But it would be nice if parsers would warn about (or even reject) programs whose meaning depends on tab width. -- Ben ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Layout rule
Ketil Malde wrote:
Multi line comments are nice for commenting out blocks of code.
They're also nice for comments within a line. E.g. haskell-src-exts contains
the declaration
data HsQualConDecl
= HsQualConDecl SrcLoc
{- forall -} [HsName] {- . -} HsContext {- = -} HsConDecl
Probably half of my uses of {- -} begin and end on the same line.
-- Ben
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Re: [Haskell-cafe] Re: Layout rule (was Re: PrefixMap: code review request)
On Wed, 2006-03-01 at 22:58 +, Ben Rudiak-Gould wrote: Duncan Coutts wrote: hIDE and Visual Haskell use the ghc lexer and get near-instantaneous syntax highlighting. Hmm... I just installed Visual Haskell 0.1, and when I type in the editor, CPU usage rises to about 70% and there's a noticeable delay before each character appears on the screen. This is a very short module (~100 lines) and a Pentium M 1600 CPU. Am I doing something wrong? I can't say too much about the internals of VH since I've not see the code, only the description. Perhaps that's because they're starting the parser immediately after every keystroke and/or not killing the parser when the user types another key. I've been using hIDE on a Pentium M 1600 laptop and on the size of modules I've tried so far it's quick. The syntax highlighting updates immediately and the type checker shows up errors a second or so after I stop typing (which is because we wait about that long before starting the parser). Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
