Please reconsider the Boolean evaluation of midnight

The rule, in its entirety, is this:

- Booleans are falsy when false.

- Numbers are falsy when zero.

- Containers are falsy when empty.

- None is always falsy.

- No other type of value is ever falsy.

I can think of two ways we might possibly want to alter the rule.

The first is to expand the idea of number to include arbitrary groups (or monoids?), with the identity element being falsy. So, for example, a matrix with all entries zero might be falsy. Or a 3-D transformation might be falsy if it does not move anything.

The second is one I have encountered in C++. There, an I/O stream is falsy if it is in an error state. This makes error checking easy; there is one less member-function name to remember. We might expand this idea to include things like Python's urllib, or any object that wraps a connection or stream of some kind.

EDIT: OTOH, there is the Haskell philosophy, where the only thing that can be evaluated in a Boolean context is a Bool, so the only falsy thing is False.

EDIT 2: The comment by clarkevans (quoting a message from INADA Naoki) already partially addressed the above group idea: "I feel zero value of non abelian group should not mean False in bool context."

This is the obvious intuition, which doesn't match the current implementation.

> Why would anyone evaluate dates in a boolean context?

I'd guess, usually to tell whether a variable has a date or None. For example, maybe you have some kind of GUI with a form where the user is supposed to fill in a time, and some variable somewhere in the code is set to None [1] when the time field is blank [2], and a time object representing the time entered by the user otherwise.

Maybe you want to require the user to fill in all fields in the form before advancing to the next step in your program's workflow. If you like falsiness, you might write:

    if not form.time_field:
        show_warning("You must enter a time to proceed")
        continue_current_phase()
    else:
        proceed_to_next_phase()

    if form.time_field is not None:

[1] None is the Python equivalent of other programming languages' null (or NULL).

[2] Or unparseable

    >>> {} + {}
    Traceback (most recent call last):
      File "", line 1, in 
    TypeError: unsupported operand type(s) for +: 'dict' and 'dict'
    >>> bool({})
    False

Those who think it this argument is pursuasive, should bool({}) raise an exception? Or should {1:"A"}+{1:"B"} not raise an exception and instead return ... what?

Or do I misunderstand something?