Calling an ABAP form SAPScript

Calling an ABAP form SAPScript
 

In Layout Set:
	DEFINE &X& = ...
        DEFINE &Y& = ...
        DEFINE &Z& = ...
        PERFORM XXXXXX  IN Zxxxxxxx
                        USING &X&
                        USING &Y&
    		CHANGING &Z&

In ABAP program Zxxxxxx
		FORM XXXXXX TABLES INPUT1 STRUCTURE ITCSY
                                                        OUTPUT1 STRUCTURE ITCSY

*get input parameters
                LOOP AT INPUT1.
                CASE INPUT1-NAME.
                                            WHEN 'X'.
               	                 INPUT_X = INPUT1-VALUE.
                                            WHEN 'Y'.
               		                INPUT_Y = INPUT1-VALUE.
     ENDCASE.
		ENDLOOP.

{logic to use program variable input_x and input_y to set say program variable output_z}

*set output variables:
	REFRESH OUTPUT1.
	OUTPUT1-NAME  = 'Z'.
	OUTPUT1-VALUE = OUTPUT_Z.
	APPEND OUTPUT1.