Hi,
Could you please check the source and target defined within the subroutine, if they are of type standard table. Hence you have to code the logic within the LOOP statement on it_source and append the corresponding values to the it_target table.
Eg:
FORM compute_data_transformation
USING it_source TYPE yt_source_fields
ir_context TYPE REF TO if_rsan_rt_routine_context
EXPORTING et_target TYPE yt_target_fields.
DATA: ls_source TYPE y_source_fields,
ls_target TYPE y_target_fields.
LOOP AT it_source INTO ls_source.
CLEAR ls_target.
* Code the logic*
APPEND ls_target to et_target.
ENDLOOP.
ENDFORM.
Regards,
Mayur Priyan. S