FM write_form

Dear All!

For SAP-Script is this below shown FM very important and elementary.

Who can say to me how can I call a window type -> var (not main)

with this FM.

Worlds all examples about sap script show how it works with

main but never an example with other window types like var or constants ?

I can't almost see this line -> WINDOW = 'MAIN'

I hope you have insight for my nervousness.

Regards

Ilhan

CALL FUNCTION 'WRITE_FORM'

EXPORTING

ELEMENT = 'INTRODUCTION'

FUNCTION = 'SET'

TYPE = 'BODY'

WINDOW = 'MAIN'

EXCEPTIONS

OTHERS = 8