New Question for ABAP....( &1 and &2 )....

Question

Dear Sir And Madams,
Cool Hii to all of you....Here once again i have stuck with a little probem... kindly help me out if you had solutons....
In one module pool coding i have found one strange thing and it is that :
  LOOP AT &1.
    &1-SEL = &2.
    MODIFY &1.
  ENDLOOP.
END-OF-DEFINITION.
DEFINE SET_SELECTION.
  &1-SIGN   = 'I'.
  &1-LOW    = &2.
  &1-HIGH   = ' '.
  &1-OPTION = 'EQ'.
  APPEND &1.
END-OF-DEFINITION.
DEFINE TOTAL.
  LOOP AT &1.
    &2 = &2 + &1-AMOUNT.
  ENDLOOP.
END-OF-DEFINITION.
DEFINE GET_DOC.
  CLEAR: IT_DOCMSTRT, &2 .
  READ TABLE IT_DOCMSTRT WITH KEY DOC_CODE = &1.
  &2 =  IT_DOCMSTRT-&3.
END-OF-DEFINITION.
DEFINE GET_DOCL.
  CLEAR: IT_DOCMSTRT, &2 .
  READ TABLE IT_DOCMSTRT WITH KEY DOC_CODE = &1.
  IF SY-SUBRC = 0.
    &2 =  IT_DOCMSTRT-&3.
    &2P = 'X'.
  ENDIF.
END-OF-DEFINITION.
DEFINE CHARGE_SET.
  CLEAR:&2.
  CASE &1.
    WHEN 'B'.
      &2 = CON_BEN.
    WHEN 'P'.
      &2 = CON_APL.
  ENDCASE.
END-OF-DEFINITION.
: Here will you explain me what is meant of '&1' and '&2' ???? by double clicking on it... navigates no where.... and asking for creating an object as per procedure of standard SAP.....
Take care....
Warm Regards,
Nirav Parekh

Answer 1

Hi Nirav,
All the piece of code below refers to definition of Macros.
Here &1 and &2 are the parameters that need to be passed to the macro.
Remember the Formal and actual parameters funda.
The Parameters &1 and &2 are the formal parameters and they will take the actual values once the Macro is used.
e.g. SET_SELECTION S_OPTION 2.
In this SET_SELECTION is the macro and S_OPTION is the actual parameter which will take place of &1.
Hence the coding will convert to
S_OPTION-SIGN = 'I'.
S_OPTION-LOW = 2.
S_OPTION-HIGH = ' '.
S_OPTION-OPTION = 'EQ'.
APPEND &1.
Regards,
Himanshu