[antlr-interest] AST generation: EXPRESSION TREE example.

Bharath Sundararaman bharath at starthis.com
Thu Jun 3 09:05:56 PDT 2004


Hi Tom,

That's pretty much where I'm at, too. I'm creating null placeholders and
using setText() method to bring out a neat AST structure which will be very
readable. Did you try the ASTFrame option to actually view the AST
structure? If you havent tried it already, 
----------------------------------------------
ASTFrame frame = new ASTFrame("My AST", ast);
frame.setVisible(true);
----------------------------------------------

Also, I found Ter's lectures on his course site (lecture notes and audio) on
ASTs extremely useful. http://www.cs.usfca.edu/~parrt/course/652/ is the
site.

Hope this helps.

Bharath.


-----Original Message-----
From: Tom Verbeure [mailto:hombre at gmail.com] 
Sent: Thursday, June 03, 2004 10:45 AM
To: antlr-interest at yahoogroups.com
Subject: Re: [antlr-interest] AST generation: EXPRESSION TREE example.


Hi Bharath,

> Thank you very much. Are you generating an abstract syntax tree for 
> your grammar, yet? I would like to know what drives your AST 
> structure. What do you need it for?

I've only just started working on it and it's going slowly. One
(trivial) thing I didn't realize up front, was that, without any
annotations, the AST tree is simply a list of all the original tokens. I
found it very useful to add

System.out.println(parser.getAST()).toStringList());

to get an idea about what was generated after building the AST.

I add a quite number of non-token nodes to tree to make tree parsing as
simple as possible. Other than that, I can't give you much useful
information. Right now, it's quite an interative process.

Tom


 
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