generic indexOf() for arrays ?

[M.Gore]

I'd like to know if there's a generic function over arrays to 
find the index of a specific elemnt therein, something like, say:

int indexOf(S) (in S[] arr, S elem);

which works the same way the std.string.indexOf() function 
works... couldn't find anything in the std.array module for this 
scenario. Would be nice to have this functionality built-in 
somehow.

Or is there a completely different / better approach to this in D?
Thx, M.