Is there a better way than what is proposed here to create a one-to-one mapping between an table view cell's NSIndexPath and a unique NSUInteger or int, in order to create a unique tag property value for a widget in the cell (a UIProgressView)?
The link adds methods through a UIKit category extension that converts between NSIndexPath and int, but they only work for less than a certain number of rows.
Granted, I may not run into that limit, but I'm wondering if there is a mapping that someone has come up with that can be guaranteed to work for any number of rows.
No, there really isn't a way that is guaranteed to work for any number of rows. If you have a table with 2 sections, each with 3 billion rows, then there's no way to map those 6 billion potential NSIndexPaths into the 4 billion 32-bit NSIntegers.
(if you were building a 64-bit app, the same thing is true, but the numbers would have to be another 4 billion times bigger in the example.)
They use a limit of 10,000 rows per section in the example you linked to; if you're seriously worried you might have more rows than that, you could use a bigger constant, i.e. you could use 1,000,000 as the maximum number of rows if you know you won't have more than 4,000 sections.
Note that a "real programmer" would presumably use 65536 as the constant, of course.