DateTime.difference() documentation could be clearer; why not have operator-?

[jamesderlin]

The documentation to DateTime.difference could be clearer about how the difference is computed. That is, instead of :

Returns a [Duration] with the difference between [this] and [other].

I think it'd be better as:

Returns a [Duration] with the difference subtracting [other] from [this].

Or instead of relying on readers to deduce it from the example code, explicitly state:

The returned [Duration] will be negative if [other] occurs after [this].

Even better would be to provide an operator - that allows one DateTime to be subtracted from the other without ambiguity.

(Dart VM version: 2.1.0 (Tue Nov 13 18:22:02 2018 +0100) on "linux_x64")

[lrhn]

The operator- on DateTime is taken by operator-(Duration difference), so we can't also use it to subtract a DateTime.
Apart from that, we should update the documentation.

[jamesderlin]

Duration has as operator-(Duration other), but I don't see any operator-(Duration difference) listed for DateTime. Am I looking in the wrong place?

[lrhn]

No, my bad. I was probably thinking of Duration.

The actual reason for not having - is probably that it felt wrong without having + (and some resistance to using +/- on things that are not numbers, or number-like like Duration).