[antlr-interest] LL-Regular / WAS: BLOG

[Terence Parr]

Heh, you're right!  It would still be possible to left factor those 
rules, however, making it slightly faster than LL-regular.

Ter

On Tuesday, October 28, 2003, at 03:26 PM, Oliver Zeigermann wrote:

> Talking to myself :)
>
> An example for a grammar that would work with LL-regular is one for
> XML start tags and empty elements
>
> startTag : LT NAME (NAME = VALUE)* GT ;
>
> emptyElement : LT NAME (NAME = VALUE)* SLASH GT ;
>
> endTag : LT SLASH NAME GT ;
>
> xmlElement
>      : startTag
>      	( xmlElement
>      	| TEXT
>         )*
>        endTag
>       | emptyElement
>     ;
>
> Becaues of the attributes, this will not work with any fixed
> lookahead, but would require syntactic predicates in ANTLR 2.x
>
> In ANTLR 3.x a regular scan ahead would do!
>
> That's good!
>
> Oliver
>
> --- In antlr-interest at yahoogroups.com, "Oliver Zeigermann"
> <oliver at z...> wrote:
>> I have just read part of the BLOG and find the idea to scan ahead with
>> an FA a very interesting idea. I noticed, I myself as a human, do
>> exactly the same when disambiguiting something in a formal language:
>> scanning ahead until you find the character you are looking for to
>> decide between the options. So, if this method does not work on a
>> grammar, the language or the grammar should be fairly unreadable for
>> humans as well.
>
>
>
>
>
> Your use of Yahoo! Groups is subject to 
> http://docs.yahoo.com/info/terms/
>
>
>
--
Professor Comp. Sci., University of San Francisco
Creator, ANTLR Parser Generator, http://www.antlr.org
Co-founder, http://www.jguru.com
Co-founder, http://www.knowspam.net enjoy email again!
Co-founder, http://www.peerscope.com pure link sharing




 

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/