Getting tree construction with ANTLR
- by prosseek
As asked and answered in http://stackoverflow.com/questions/2999755/removing-left-recursion-in-antlr , I could remove the left recursion
E - E + T|T
T - T * F|F
F - INT | ( E )
After left recursion removal, I get the following one
E - TE'
E' - null | + TE'
T - FT'
T' - null | * FT'
Then, how to make the tree construction with the modified grammar?
With the input 1+2, I want to have a tree ^('+' ^(INT 1) ^(INT 2)). Or similar.
grammar T;
options {
output=AST;
language=Python;
ASTLabelType=CommonTree;
}
start : e - e
;
e : t ep - ???
;
ep :
| '+' t ep - ???
;
t : f tp - ???
;
tp :
| '*' f tp - ???
;
f : INT
| '(' e ')' - e
;
INT : '0'..'9'+ ;
WS: (' '|'\n'|'\r')+ {$channel=HIDDEN;} ;
