Search program in 'PERFORM subroutine(program)'

Hi,

What is the best way to find the <b>program</b> name in PERFORM subroutine(<b>program</b>) in customized programs?

I have been making use of RPR_ABAP_SOURCE_SCAN, but this std prog only allows (1)first level of drill down

(1)Example:

Main program ZABC.

PERFORM sub1(ZSUBPROG).

-

Subprogram ZSUBPROG.

PERFORM sub2(ZSUBPROG2).

For the above, i need to have the result returns me both subprogram <b>ZSUBPROG</b> and <b>ZSUBPROG2</b>.

-

My second problem would be difficult to (2)merely extract the sub program name alone since there is a lot of pattern of syntax declaration for PERFORM xxx(ZXXX).

(2) Example:

a.   PERFORM xxx(ZABC)         .
b.  PERFORM: xxx(ZABC),
                       xxx(ZEFG),      "perform xxx(ZEFG)
          .
c. PERFORM: xxx(ZABC), xxx(ZEFG)    .

Pls comment is there is any std FM or any tools can help.

Thanks in advance.