Re: Planning Project to use YAPP - confused on AST Tree Walker

Hello,

Interesting question, made me think about parsing issues again.
Using XML for intermediary or cross-language formats indeed has  
massive advantages, and I think we'll see much more of such formats  
in the future.

Antlr does have a strong treewalker component, though I've found it  
difficult to work with when generating XML (or xml-like) output.

The idea with YAPP is that you feed a grammar (in XML format) as the  
input and you get a parser (an xsl stylesheet) as output.
The example with the BNF parser is a bit like pulling oneself up by  
the straps of one's boots. The resulting BNF parser can parse text- 
based BNF grammars into the XML format that is used to drive the two  
main xsl's.
Note that YAPP is more a proof of concept than a production-grade  
tool - ultimately XSLT is not the best language for writing high- 
performance parsers in.

Another o:XML-related project you might want to check out is MLML  
[1], which aims to be an XML format for representing almost any  
programming language. It would work very well as the basis for a  
Javascript representation in XML. There are also some tools available  
for MLML already, for generating JavaDoc-style documentation in  
DocBook and HTML, and for producing XMI-format class diagrams.
Writing an XSLT stylesheet that can generate valid ECMA Script code  
from a decent XML-based format should not be too difficult.
There is also a framework for compiler construction based on MLML  
which was created for a commercial, production-grade compiler project  
- the GPL-licenced portion of the code is in CVS here [2].

I'd be very interested to hear how you progress with this project, so  
keep us updated!

regards,

/m

[1] http://www.o-xml.org/projects/mlml.html
[2] http://cvs.pingdynasty.com/viewcvs/mlml/


On 19 Apr 2007, at 0:53, Cefn Hoile wrote:

> I've been seeking a suitable XML format and supporting toolset to  
> store both an abstract grammar and the mapping from an instance of  
> the grammar (abstract syntax tree) to executable programs in a  
> target language.
...