[antlr-interest] XML island grammar

[David Holroyd]

On Sun, Oct 07, 2007 at 10:34:42PM -0700, Matthieu Riou wrote:
> I have a main grammar that can embed some pieces of XML. A bit like E4X in
> Javascript if you're familiar with the language. I'd like to handle this
> with an island grammar but I'm not so clear on how to do detect the XML
> block. I've had a look at the javadoc island grammar example which gives me
> a pretty good idea of how to delegate parsing. However detecting XML in the
> middle of some code is not as simple as with Javadoc (you can assume /** to
> be a uniquely used token but not <).
> 
> Here is a code snippet of what I'm trying to parse:
> 
> process ExternalCounter {
>   receive(my_pl, start_op) (msg_in) {
>     resp = <message><counter>0</counter></message>
>     while(resp.counter < 10) {
>       invoke(partner_pl, partner_start_op) (msg_in)
>       resp = receive(partner_pl, partner_reply_op)
>     }
>     reply resp
>   }
> }

I've hacked together some stuff that tries to handle this kind of thing.
The overview is that I do a bit of extra admin in order to have the
parser 'direct' the lexical interpretation of the input, and
specifically avoid ANTLR's default behaviour of lexing all input at
startup.


See a slightly old description here,

  http://www.antlr.org/wiki/display/ANTLR3/Island+Grammars+Under+Parser+Control


I have a partial E4X grammar (actionscript4 is basically ECMAscript).
See,

  Main grammar:
  http://svn.badgers-in-foil.co.uk/metaas/trunk/src/main/antlr/org/asdt/core/internal/antlr/AS3.g3

  Helper glue code:
  http://svn.badgers-in-foil.co.uk/metaas/trunk/src/main/java/uk/co/badgersinfoil/metaas/impl/parser/E4XHelper.java

  E4X grammar (incomplete):
  http://svn.badgers-in-foil.co.uk/metaas/trunk/src/main/antlr/uk/co/badgersinfoil/metaas/impl/parser/e4x/E4X.g



hope that helps,
dave

-- 
http://david.holroyd.me.uk/