Dynamic computation

Question

hi all,
i need to compute the result given a formula that is extracted from a table with character field. sort of converting the text into a numeric formula. i've been trying to use macro, compute and class but to no avail as it always produce dump due to conversion (char to numeric). my last recourse would be to dynamically create a program. is there an easier way? your help/input would be greatly appreciated.
ex.
table: ztab.
field: fld1(120).
ztab-fld1 = ( PRICE_AMT / 0.1 ) * 0.98
the PRICE_AMT is to replaced with a corresponding value.
Thanks,
emcc

Answer 1

Hi emcc
Here is a snippet of code which I roughly wrote. I hope it satisfies your requirement. It still needs some optimization. Here, the program replaces all occurences of <b>'&'</b> with the input <b>"ip_par1"</b> in the formula input via the parameter <b>"ip_form"</b>. Then it generates a subroutine-pool to calculate the formula. You may extend it to support more than one parameter. As I remember, in 4.7+ there is a new statement as <b>"REPLACE ALL OCCURRENCES OF <str> IN <str> WITH <str>"</b> which may replace the DO-loop .
<b>REPORT dynamic_calculate .
DATA: BEGIN OF gt_itab OCCURS 1 ,
        line(80) TYPE c ,
      END OF gt_itab .
PARAMETERS: ip_form(120) .
PARAMETERS: ip_par1(10) .
START-OF-SELECTION .
  DATA gv_result TYPE i .
  DATA gv_name(30) TYPE c .
  DATA gv_err(120) TYPE c .
  DATA gv_index LIKE sy-fdpos .
  DATA gv_fore(30) TYPE c .
  DATA gv_back(30) TYPE c .
  DATA gv_formula(120) TYPE c .
  gv_formula = ip_form .
  gt_itab-line = 'REPORT generated_forms.' .
  APPEND gt_itab .
  gt_itab-line = 'FORM calculate CHANGING ep_result TYPE i . ' .
  APPEND gt_itab .
  DO .
    REPLACE  '&' WITH ip_par1 INTO gv_formula .
    IF sy-subrc NE 0 .
      EXIT .
    ENDIF .
  ENDDO .
  CONCATENATE 'ep_result =' gv_formula '.'
   INTO gt_itab-line SEPARATED BY space .
  APPEND gt_itab .
  gt_itab-line = 'ENDFORM.' .
  APPEND gt_itab .
  GENERATE SUBROUTINE POOL gt_itab NAME gv_name MESSAGE gv_err .
  PERFORM calculate IN PROGRAM (gv_name) CHANGING gv_result
                 IF FOUND .
  WRITE:/ gv_err .
  WRITE:/ gv_result .</b>
*--Serdar