Static widget can't handle [] properly

[tibetsam]

Have you checked closed issues? (https://github.com/Textualize/textual/issues?q=is%3Aissue+is%3Aclosed)
yes

Have you checked against the most recent version of Textual? (https://pypi.org/search/?q=textual)
yes
~> pip3 show textual
Name: textual
Version: 2.1.1

The bug

MarkupError: Expected markup style value (found '00] foo bar').

from textual.app import App, ComposeResult
from textual.widgets import Static


class FailedStatic(App):
    def __init__(self):
        self.text = None
        super().__init__()
    def compose(self) -> ComposeResult:
        yield Static(f"Textual cannot handle bracket [00] foo bar", id="line-content")



app = FailedStatic()
if __name__ == "__main__":
    app.run()

[github-actions[bot]]

We found the following entries in the FAQ which you may find helpful:

• How do I center a widget in a screen?
• No widget called TextLog

Feel free to close this issue if you found an answer in the FAQ. Otherwise, please give us a little time to review.

This is an automated reply, generated by FAQtory

[Zaloog]

Hi @tibetsam Static takes a rich renderable, you have to escape the squared brackets, so they are not interpreted as styles like
e.g. coloring it red "[red] red string[/]".

This fixes your string f"Textual can handle escaped bracket \[00] foo bar" :)

[willmcgugan]

You can also set markup=False on the widget to not process markup.

https://textual.textualize.io/guide/content/

[boeddeker]

Is there a way to automatically escape a string to make it valid for textual?
For example,

rich.print("Toggle [1, 2] Me")

works as expected, but for widgets, the string causes problems (See example at the bottom).
I found rich.markup.escape and textual.markup.escape, but both don't escape the [ in Toggle [1, 2] Me.

Motivation: I have arbitarty python code, that I want to show as title of a Collapsible.
My workaround is to manually .replace('[', '\['), but it would be nice to have
widgets to accept what rich.print expects or an escape function that yields a valid string for widgets.

Here a small example, where it fails:

import textual.app
import textual.widgets
import textual.markup

class CollapsibleExample(textual.app.App):
    def compose(self):
        yield textual.widgets.Collapsible(
            textual.widgets.Label("Inside!"), 
            title=textual.markup.escape("Toggle [1, 2] Me"),  # <-- The "[" causes the error
            # title="Toggle [1, 2] Me",  # <-- also fails
        )

if __name__ == "__main__":
    CollapsibleExample().run()