How does this compile???????

[erikzcai]

How does this code fragment compile?

Notice the word "and" in the string declaration

        Procedure OnConstrain 
            Boolean bShowNonInvent bNew bEdit bDelete bAll
            Date dStart dStop
            String sInit sStart and sStop
            Get Value of oInit to sInit
            Get Value of oStartDate to dStart
            Get Value of oStopDate to dStop
            If (trim(sInit)<>'') Constrain Invdaudt.Init eq sInit
            If (dStart<>'') Constrain Invdaudt.Date ge dStart
            If (dStop<>'') Constrain Invdaudt.Date le dStop
            .
            .
            .
        End_Procedure