Hmm, I am afraid I found the answer: Under most circumstances, if you get or set an object property using the dot operator, IDL will call the object's GetProperty or SetProperty method. However, if inside of a method you get or set a property of the self object, IDL will access the property directly. If this is tue it's kind of bizar, two different things that go by the same identifier. Apparently there's no distinction between the property and the underlying variable.

Here's a fun trick to get around this. Rather than specifying "print, self.x", try using the syntax "print, (self).x" when your intent is to call ::getproperty or ::setproperty. Alternatively, create a copy of self first, for example "s = self & print, s.x". There should only be a slight hit to execution since you're only copying the object reference or treating it as an expression. I'd offered to write a IDL blog post on this entitled "Not feeling like my self", but the idea was shot down. :-(

Send it to me. I'll publish it under Coyote's byline. :-)

Jim Pendleton wrote: try using the syntax "print, (self).x" when your intent is to call ::getproperty or ::setproperty. Alternatively, create a copy of self first, for example "s = self & print, s.x". Jolly good trick! Only my IDL is not fooled by the first one (=(self).x )

I stand corrected. Putting my self into a parenthetical expression (something I am known to do in real life) frequently fails to lead me to the expected outcome. Life's lesson learned again.