Combine combinations and with_replacement_combinations

[ararslan]

It might be worthwhile to combine the combinations and with_replacement_combinations functions. I could see a potential API as

combinations(x, n)               # No replacement
combinations(x, n, replace=true) # With replacement

Having separate functions was probably worthwhile in The Olden Days, when keyword arguments were a performance killer and value-based dispatch with Val didn't exist.

[Nosferican]

Might be nice to have this for permutations as well.

[ignaciomartin]

I subscribe to this proposal, both for combinations and for permutations. It could be interesting to use the same R arguments:
https://rdrr.io/cran/arrangements/man/permutations.html

[Moelf]

from google search to this issue, thus bump