What do these operators do in D 2.0: <>= !<>= !<= !>=

Question

What do these operators do in D 2.0:

• <>=
• !<>=
• !<=
• !>=

Answer 1

They are used for values that could be unordered, such as NaN for floats and doubles. 1 <>= NaN evaluates to false, whereas x <>= y evaluates to true for any pair of numbers, as long as neither number is NaN. The other operators you mention work the same, mutatis mutandis.