ANTLR3: how to map the instructions in AST to line number in its java source file

Question

How to find the line numbers(of source file) of instructions from AST.

example:

for the following code

24> void foo(){

25> System.out.println(" hi ");

26> }

the ast corresponding to print statement is

         METHOD_CALL
              .
                 .
                    System
                    out
                 println
              ARGUMENT_LIST
                 EXPR
                    " hi "

I want to retrieve the line number of "System" from the generated Tree. The answer for "System" should be 25(line number in the source code).

Answer 1

If your Tree for the System token is in fact a CommonTree, then you can use the CommonTree.getToken() method to get the Token for Symbol. You can then call Token.getLine() to get the line number.