[antlr-interest] Newbie questions

[Vaclav Barta]

Adnan Siddiqi wrote:
 > confusion for me that how to extract data after successful parsing?
Well, there's a couple of ways...

 > Let me explain you further that I have to create a SQL QUERY like
 > language for a web portal where different 'custom objects' would be
 > add/retrieved by using SQL like language. for example:
 >
 > "Select objModule from Module Respositoary where @type='entertainment' "
 >
 > now lets suppose i successfully generate grammer and parse as well by
 > using ANTLR generated code. Now How do I pick required 'objModule' of
 > type ='entertainment'? can ANTLR allows to make custom functions
 > which should be parsed after successful parsing? if not then should I
Yes, that's one way - they're called actions, can be specified as part 
of your grammar and can contain any Java code you need at that point.

 > pick values from SYMBOL TABLE?
There's another way, where you just generate AST (abstract syntax tree)
and work on it outside the grammar (i.e. by writing _another_ so called
tree parser), but I really wouldn't recommend that - that way didn't 
exist in 1998 (other than as a gleam in some computer scientist's eye 
:-) ), so you haven't seen it before, and I fail to see the advantages 
of complicating my parsing that way - but of course, perhaps it's just 
because I don't understand...

	Bye
		Vasek

P.S.: If you're doing something like SQL, there's an SQL grammar (for 
the previous version of ANTLR) at 
http://www.antlr.org/grammar/1062280680642/MS_SQL_SELECT.html , which I 
found quite useful.