Tested the speed difference IIRC in vfp6, there == with !datatypes =="C" perf was slightly lower, whereas it was slightly faster with datatype=="C",
and back then vfp was getting new versions, so we used it only with Char/Strings as to be certain a future version would not bark on the code

>Without looking at your code, == is supposed to be just an exact *string* comparison: https://msdn.microsoft.com/en-US/library/3b6st626%28v=vs.80%29.aspx . It's interesting that it "works" - or at least doesn't give errors - if used with other data types. I haven't seen it used for other data types in VFP before, although it is a convention in other languages. You're thinking outside the box ;)