I've been playing around with the polygon editor in the SQ5 code (via the SCI1.1 template game), and it crashes in Scumm with a "signature mismatch" for kPrevNode when adding the second polygon point.
PolyEdit::saveForUndo passes a node value to the prev method of a List, which then calls PrevNode with the node value (instead of the node handle). It looks like Scumm expects only a node handle.
From the code in PolyEdit, it seems that PrevNode (et al) in Sierra's interpreter must have been able to handle node values in addition to node handles? I'm not sure how, since if the same value appeared in different nodes, how could it do the reverse mapping? Nonetheless, that's what the code does (it also expects a node value returned from PrevNode, instead of a handle). The code in LSL6 is identical too.
Actually, come to think of it, it just may be a bug in Sierra's code - as long as the bad code didn't crash the interpreter (it doesn't), it's possible it might not be terribly noticeable - it just breaks the undo functionality of their polygon editor.
[edit:] Also, the polygon editor code calls the Atan kernel, which is unimplemented in Scumm. Sierra's interpreter freezes when I try to exit and save the polygon, and I'm trying to debug it - but I'm having trouble doing that with Scumm because I can't even get that far
. I'll remove the Atan call (which appears to be part of validation) and keep trying...
