[antlr-interest] multiple tree walkers

[Oliver Zeigermann]

Hi Michael!

I do the same thing and have the same concerns. I have no better
solution now, but ANTLR 3.2 will feature pattern based tree rewriting
which might solve this:

http://www.antlr.org/wiki/display/~admin/2008/11/30/Example+tree+rewriting+with+patterns

I set up a page where I share my experience with multiple tree
transformer stages:

http://www.antlr.org/wiki/display/ANTLR3/Complex+tree+transformations+using+cascading+tree+rewriters

Maybe you would like to add yours?

-Oliver

2009/2/9 Michael Bedward <michael.bedward at gmail.com>:
> Hi folks,
>
> I'm working on a little DSL, called jiffle, to create raster images
> from maths expressions.  I build an initial AST from the input jiffle
> script, and next use a couple of tree walkers to (1) check for
> undefined vars and (2) categorize vars on whether thay depend on pixel
> position or not.
>
> The grammar for each of these tree-walkers is essentially the same as
> that for the token parser, except that only a very small number of
> rules / sub-rules have actions.  Everything is working swimmingly at
> the moment - but I'm concerned that this approach of cloning a grammar
> might be prone to error as the language evolves since it depends on
> keeping all of clones in sync.
>
> Are there other approaches / best-practices for writing multiple tree walkers ?
>
> cheers
> Michael
>
> List: http://www.antlr.org/mailman/listinfo/antlr-interest
> Unsubscribe: http://www.antlr.org/mailman/options/antlr-interest/your-email-address
>