"bg fld" vs "cd fld" in Hypercard/Hypertalk

Question

I'm up to porting an old application built in Hypercard to make use of the latest Mac OSX speech synthesis capabilities. What is the difference between

bg fld

and

cd fld

in Hypercard?

Thanks.

Answer 1

bg fld == background field, cd fld == card field

Every card has two layers, the background layer (which can be shared by several cards) and the card layer. A background is something like a master slide in Keynote. Text fields that you create on the background layer may (if their sharedText is FALSE) have different contents on each card.

E.g. when you make a database, you can define the different record fields for a database entry as background fields, then enter a different person's details on each card to use it as a database entry.

Answer 2

As already answered:

bg fld == background field, cd fld == card field

Also worth noting is that the "bg" or "background" identifier is the default, so any references to simply "fld" or "field" are just alternate ways of writing "bg fld" or "background field".