manim/tests/module/mobject/text
Benjamin Hackl 000e7792bd
fix: MathTex double-brace splitting no longer fires on natural LaTeX }} (#4602)
* fix: replace double-brace splitting regex with state-machine parser

The previous re.split(r'{{|}}', ...) call split on any occurrence of
{{ or }} in the input string, which broke strings whose only }} came
from closing two nested LaTeX brace groups (e.g. ^{\frac{Mq}{M+m}}).

The new _split_double_braces() static method uses a character-level
state machine with three guards:

* Escape priority: \\ is consumed before \{ / \}, so \\}} is
  correctly read as an escaped backslash followed by a real }}, not
  misinterpreted as \ + \} + lone }.

* Whitespace-gated opener: {{ is only treated as a Manim group opener
  at the start of the string or after whitespace. Naturally-occurring
  {{ in LaTeX is usually preceded by non-whitespace (e.g. \frac{{{n}}}
  or a^{{2}}), so this eliminates the most common false positives.

* Depth-tracking closer: inside a Manim group, }} only closes the
  group when the inner brace depth is zero, so {{ a^{b^{c}} }} is
  handled correctly and nested LaTeX }} cannot trigger an early close.

Fixes #4601.

* docs: document double-brace whitespace requirement

Add a Notes section to the MathTex docstring explaining:
- how {{ }} splits a string into submobjects
- that {{ must be at start-of-string or preceded by whitespace
- that this leaves natural LaTeX like \frac{{{n}}}{k} untouched
- the { { ... } } escape hatch when a split is not wanted

Apply the same explanation to the double-brace paragraph in
docs/source/guides/using_text.rst.

* fix: use r-string for _split_double_braces docstring, halve backslash escaping
2026-02-22 10:48:51 +01:00
..
test_markup.py [pre-commit.ci] pre-commit autoupdate (#4035) 2025-01-19 18:08:36 +01:00
test_numbers.py Standardize docstrings with ruff pydocstyle rules (#3881) 2024-09-01 08:03:38 -04:00
test_texmobject.py fix: MathTex double-brace splitting no longer fires on natural LaTeX }} (#4602) 2026-02-22 10:48:51 +01:00
test_text_mobject.py Standardize docstrings with ruff pydocstyle rules (#3881) 2024-09-01 08:03:38 -04:00