Calculating the size of Array::pack format string

Question

How do you calculate the length of the string that would be returned by Array::pack? Is there something like Python's calcsize?

Answer 1

By making an interpreter complying to the specifications found in Array::pack.

Or, reusing the existing implementation to count the number of characters instead of appending them to a string.

Answer 2

array.pack("").count I would say. Not really the fastest method, but it works.