What is the point of conditional statements?

Submitted by pacermike on Fri, 2010-10-08 17:31

I start a new session of Max and type into the Listener:

custAttributes.getScenedefs()

It returns:

#()

Ok, sweet. There are no definitions in the scene.

Then, I run this piece of code:

if selection.count == 1 and selection[1].baseobject.custAttributes.count == 0 then
(
if sceneDataCADef == undefined do
(
	sceneDataCADef = attributes sceneDataCA version:1 attribID:#(0x61e9ff5f, 0x63784819)
	(
		parameters main rollout:params
		( note type:#string ui:et_note default:"" )
		rollout params "Scene Data Parameters"
		( edittext et_note "Note: " )
	)
)
custAttributes.add selection[1].baseobject sceneDataCADef
)
else false

This returns:

false

I type in to the Listener again:

custAttributes.getScenedefs()

It now returns:

#(<AttributeDef:sceneDataCA>)

What the eff is going on? The very first line of the code:

selection.count == 1 and selection[1].baseobject.custAttributes.count == 0

evaluates FALSE! Why does it continue to create an Attribute Definition when the very first line of the code should be telling it to stop?

Any ideas?

Thanks!

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pacermike's picture
Submitted by pacermike on Fri, 2010-10-08 18:49.

Another Test

The conditional statement without the Attributes Definition:

if $selection.count == 1 and $selection[1].baseobject.custAttributes.count == 0 then 
(
	box()
)	
else 2 + 2

Returns:

4

But if I change the conditional statement so that it's true, like this:

if $selection.count == 0 or $selection[1].baseobject.custAttributes.count == 0 then 
(
	box()
)	
else 2 + 2

It creates a box.

So the conditional statement seems to be working just fine... until I put an Attributes Definition in the code which it seems to evaluate whether I want it to or not.

Why?!

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