Dumb Newbie Questions -- 1 of N

[Scott Rossi]

Recently, Judy Perry wrote:

> I'm trying to figure out what new (to me) things are worth spending time
> on this summer (worth = useful for me) and which are not.  I honestly do
> not see myself doing 32,000 card stacks anytime soon as my little things
> are just educational aids for my kids, so I thought I'd pick custom
> properties since everyone seems to be of the opinion that they are the
> bee's knees. Howevder, I need to see an example along the lines of the
> sorts of things I'd be likely to use them for as well as an extremely
> detailed set of instructions with explanations of why as well as how.

Judy, maybe this analogy can help:

You can think of custom properties as global variables that are tied to
objects, instead of variables that float around in space.

You know how to use globals, yes?  If you script:
  global specialValues
  put "a,b,c" into specialValues

...you've created a global variable named specialValues that is accessible
everywhere in your stack.  And to use the contents of specialValues, you
simply declare the variable and do something with it:
   global specialValues
   answer specialValues

The above is similar for custom properties, except that you assign the
"global" to an object:
  set the specialValues of btn 1 to "a,b,c"

In scripting this, you have created a custom property of button 1 called
specialValues, and you can retrieve the contents of the property anywhere in
your stack by referencing the object to which the property is attached:
   answer the specialValues of btn 1

Notice that you need to use the word "the" when accessing a custom property,
the same way you would script "the backColor of btn 1" or "the width of btn
1".  Now, in addition to backColor and width properties, button 1 also has a
specialValues property -- a property you created.

So while a custom property is not a global variable from a semantic
standpoint, it does behave a bit like a global variable, but one that is
assigned to an object, and the object can be a control, a card, or a stack.

I think this has been stated before, but one reason I use custom properties
so often in my stacks is the values stored in them are persistent across
sessions, whereas globals need to be populated each time.  I also like the
fact that custom properties are no longer present after a stack is closed,
unlike globals which hang around in memory until they are deleted or Rev is
shut down.

Finally, the association that can be made between and object and a custom
property makes sense to me.  I can set the "bouncing" property of a ball
image to true or false; if I have many ball images in a stack, they can all
have the same "bouncing" property which I can check on an object-by-object
basis.

Hope you find this somewhat useful.

Regards,

Scott Rossi
Creative Director
Tactile Media, Multimedia & Design