nextPermutation and ranges

[bearophile]

H. S. Teoh:

> any implementation based on factorial would have to
> address the issue of how to handle the exponential growth. I 
> think it'sunacceptable for the standard library to support
> permutations only up to ranges of 20 elements or less,
> because 21! > 2^64.

What are the use cases of generating the permutations of a set of 
items higher than abot 20? (in my code I don't remember having to 
permute more than few items.)

One thing I was forgetting: thank you for your work H. S. Teoh.

Bye,
bearophile