SAP provides a conversion for SAPscript into SMARTforms.
There are two way through which you can convert sapscript into smartforms.
(1)
This is basically a function module, called FB_MIGRATE_FORM.
You can start this function module by hand (via SE37), or create a small ABAP which migrates all SAPscript forms automatically.
(2)
You can also do this one-by-one in transaction SMARTFORMS, under
Utilities -> Migrate SAPscript form.
You could also write a small batch program calling transaction SMARTFORMS and running the migration tool.
Note :
While Converting sapscript into smartforms,only layout has passed.But you have do all logic coding in your smartforms.
Steps :
(1) Understand logic of sapscript program.
(2) Understand SAP script windows data.
Now make your technical Design Accordingly,and now do code accordingly for your smartforms.