[antlr-interest] Parse trees

[Adrian Sandor]

Hi, I'm using antlr 3 and trying to get a parse tree.
I followed the instructions from http://www.antlr.org/wiki/pages/viewpage.action?pageId=1760 and I have some questions:
- in the example from that page, why does the parser accept a statement ending in a semicolon? ("i=4;")
- I modified the grammar to this:

grammar P;
prog: decl* stat* ;
decl: type ID (',' ID)* ';' ;
type: 'int' | 'float' ;
stat: ID '=' expr;   
expr: OP* simple (OP+ simple)* OP*;
simple: INT;
        
ID  : 'a'..'z'+ ; 
INT : '0'..'9'+ ;
OP: '+'|'-';
WS  : (' '|'\n')+ {$channel=HIDDEN;} ;

and the input to this:

int i;
i=1+ -2+3

This time it complained about a semicolon in the statement, so I removed it. But the problem is that the resulting parse tree looks like this:
(<grammar prog> (prog (decl (type int) i ;) (stat i = (expr (simple 1) + - 2 + - (simple 2) + 3 + (simple 3)))))

What's going on? Is this a bug?

Thanks
Adrian



      
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