Version: R13B01
Documentation:
===
usort(Fun, List1) -> List2
Types Fun = fun(Elem1, Elem2) -> bool()
Elem1 = Elem2 = term()
List1 = List2 = [term()]
Returns a list which contains the sorted elements of List1 where
all but the first element of the elements comparing equal
according to the ordering function Fun have been deleted. Fun(A,
B) should return true if A comes before B in the ordering, false
otherwise.
===
Actual behavior:
18> lists:usort(fun(A, B) -> A < B end, [a, a]).
[a,a]
19> lists:usort(fun(A, B) -> A =< B end, [a, a]).
[a]
20> lists:usort(fun(A, B) -> A >= B end, [a, a]).
[a]
21> lists:usort(fun(A, B) -> A > B end, [a, a]).
[a,a]
22>
Contradicts description "should return true if A comes before B in the
ordering, false otherwise".
--
Lev Walkin
vlm@REDACTED