H. S. Teoh:
any implementation based on factorial would have toaddress the issue of how to handle the exponential growth. I think it'sunacceptable for the standard library to supportpermutations 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
