xmlgraphics-fop-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Vincent Hennebert <vhenneb...@gmail.com>
Subject Re: Questionable whether font-shorthand grammar LL(1)
Date Wed, 30 Sep 2009 10:39:29 GMT
Hi Jonathan,

Jonathan Levinson wrote:
> Hi Vincent,
> 
> Excellent ideas!  
> 
> The diagram you drew is extremely useful!
> 
> If the font shorthand sub-language has a grammar that is regular then it also has a grammar
that is LL(1).  So recursive descent parsing will work, if there is a regular grammar.
> 
> I think the best way of getting font shorthand to work would proceed in stages:
> 
> 1) First get the current code to properly parse and accept valid font shorthand expressions.
 This should be very easy.  The one remaining problem (AFAIK) is the parsing of font-size/line-height
where /line-height is optional.   Currently spaces are not allowed around the slash "/" and
they should be.  I'm going to try to get to this problem as soon as I have time, probably
in a day or so.

The current code predates the switch to Java 1.4 as a minimum
requirement, so couldn’t use the java.util.regex package. Feel free to
make use of regular expressions if you think that will make the job
easier.


> 2) Evaluate which parser or automaton approach is the simplest and produces better error
states than the current approach.  
> 3) Implement the approach one has chosen in (2).

Good luck!

<snip/>

Vincent

Mime
View raw message