As a practice and learn session, I'd like to construct a FileMaker
calc field that "looks" at a credit card number in a field, and then
ID the card based on the first number, and then show the credit card
CC_number <= CC number entered into this field.
CC_ID.c <= CC type identified in this field.
This simple calc is obviously wrong, but describes what I think it
logically looks like (identify the first number and relate that to the
if (left 1, 3, "AMEX"),
if (left 1, 4, "Visa"),
if (left 1, ...