Proposed modifications for the example of "Widgets"

[jrycw]

This issue is intended to propose modifications to the example provided in guide/widgets, and the original code can be accessed here.

• In reality, the on_bit_switch_bit_changed of ByteEditor receives BitSwitch.BitChanged but does not use it. Consequently, there is no need to pass the bit and value to BitSwitch.BitChanged while initializing.

• The value(textual.reactive.reactive) in BitSwitch appears to indicate the switch status (on/off). Therefore, it seems more natural to use value = reactive(False) instead of value = reactive(0).

To summarize, I would suggest modifying BitSwitch with the following code:

class BitSwitch(Widget):
    """A Switch with a numeric label above it."""

    DEFAULT_CSS = """
    BitSwitch {
        layout: vertical;
        width: auto;
        height: auto;
    }
    BitSwitch > Label {
        text-align: center;
        width: 100%;
    }
    """

    class BitChanged(Message):
        """Sent when the 'bit' changes."""

    value = reactive(False)

    def __init__(self, bit: int) -> None:
        self.bit = bit
        super().__init__()

    def compose(self) -> ComposeResult:
        yield Label(str(self.bit))
        yield Switch()

    def watch_value(self, value: bool) -> None:
        """When the value changes we want to set the switch accordingly."""
        self.query_one(Switch).value = value

    def on_switch_changed(self, event: Switch.Changed) -> None:
        """When the switch changes, notify the parent via a message."""
        event.stop()
        self.value = event.value
        self.post_message(self.BitChanged())

[rodrigogiraoserrao]

Hey @jrycw, thanks for opening this issue!

We represent BitSwitch.value with a switch because bits are commonly thought of in terms of on/off, like you said, but BitSwitch.value is the value of the binary expansion of the number in that bit, so it makes sense to keep it as an integer.
I'll go through the example to make sure it's clear when we're working with integers vs Booleans.

As for the event accepting the bit and value parameters, I believe the author of that guide added them because those are sensible things to include in that sort of message...
But it may be confusing for people reading the code because they can't see those parameters being used...
Point taken.

[rodrigogiraoserrao]

Apparently the remainder of the code also thinks BitSwitch.value is a Boolean, so I'll go with your suggestion!

[rodrigogiraoserrao]

See the PR linked above for the resolution of this issue.

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