From: Vladimir Prus (ghost_at_[hidden])
Date: 2001-05-24 06:31:59
Joel de Guzman wrote:
>> 1. Potential scope
>> Joel, could you make some more grammars and give performance results
>> compared with traditional parsers, time needed to write and debug parsers,
>> and so on?
>> (Besides, your code fails to compile under g++ 3.0 and bcc 5.5.1).
>My first priority is to compile Spirit with g++ and bcc.
I've done it. You just have to check if my changes are ok from semantical
>As for more grammars and performance analysis, that would involve
>more time. But certainly that's something I intend to do.
>>It is therefore necessary to establish which grammars are suitable.
>>This can be done through experiment only.
Greg Colvin wrote:
>And by understanding, theoretically, just what kind of parser
>Spirit is, and what the known performance characteristics of
>that kind of parser are.
>That said, ease of use is much more important than performance
>for the kind of things I imagine Spirit being used for.
Joel de Guzman wrote:
>Scope? Well admittedly, the original intent of Spirit is for small to
>medium sized grammars. Internet protocols, files, html, xml, scripting
>languages, possibly basic variants, pascal variants, pre-processors,
>resource description, lexers, and yes I intend to use Spirit as an engine
>for another parser.
Theoretical study is not likely do give us much. Backtraing parser have
exponetial complexity in worst case, and "high priests" would find their use
> BTW, could you give me a parser that does not choke on C++?
Well, EDG folks somehow managed to parse the language :-).
>> 2. Syntax
>> Proposed syntax has prefix "*" and "+". This is likely to confuse anyone
>> knows what EBNF is. Reuben Fries and later David Abrahams have already
>> proposed different syntax. Is it better? I tend to say "yes".
Well, our opinions differ. So, we need, as Greg Colvin put it, "argument
and experimentation towards finding a nice, clean syntax.". I don't believe
any argument can be usefull there -- too much is based upon personal
The iterator syntax, apart from being more verbose (and clutters
the grammar), requires more time to comprehend. I'd say go for both. I tend
to agree on the infix + instead of >> for sequencing though.
>> 3. Possible extensions
>> Douglas Gregor's idea of compiling Sprint expression looks very neat. I
>> that if some automata building libary is available, it can be easily
>> accomplished. However, such a library should be completely independent
>Agreed. this is a really cool avenue to explore.
Well, see my parallel post exactly on this subject.
-- Regards, Vladimir
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