Method __init__

lib/matplotlib/_mathtext.py:2099–2291

(self)

    _latin_alphabets = set(string.ascii_letters)

    def __init__(self) -> None:
        p = types.SimpleNamespace()

        def set_names_and_parse_actions() -> None:
            for key, val in vars(p).items():
                if not key.startswith('_'):
                    # Set names on (almost) everything -- very useful for debugging
                    # token, placeable, and auto_delim are forward references which
                    # are left without names to ensure useful error messages
                    if key not in ("token", "placeable", "auto_delim"):
                        val.set_name(key)
                    # Set actions
                    if hasattr(self, key):
                        val.set_parse_action(getattr(self, key))

        # Root definitions.

        # In TeX parlance, a csname is a control sequence name (a "\foo").
        def csnames(group: str, names: Iterable[str]) -> Regex:
            ends_with_alpha = []
            ends_with_nonalpha = []
            for name in names:
                if name[-1].isalpha():
                    ends_with_alpha.append(name)
                else:
                    ends_with_nonalpha.append(name)
            return Regex(
                r"\\(?P<{group}>(?:{alpha})(?![A-Za-z]){additional}{nonalpha})".format(
                    group=group,
                    alpha="|".join(map(re.escape, ends_with_alpha)),
                    additional="|" if ends_with_nonalpha else "",
                    nonalpha="|".join(map(re.escape, ends_with_nonalpha)),
                )
            )

        p.float_literal  = Regex(r"[-+]?([0-9]+\.?[0-9]*|\.[0-9]+)")
        p.space          = one_of(self._space_widths)("space")

        p.style_literal  = one_of(
            [str(e.value) for e in self._MathStyle])("style_literal")

        p.symbol         = Regex(
            r"[a-zA-Z0-9 +\-*/<>=:,.;!\?&'@()\[\]|\U00000080-\U0001ffff]"
            r"|\\[%${}\[\]_|]"
            + r"|\\(?:{})(?![A-Za-z])".format(
                "|".join(map(re.escape, tex2uni)))
        )("sym").leave_whitespace()
        p.unknown_symbol = Regex(r"\\[A-Za-z]+")("name")

        p.font           = csnames("font", self._fontnames)
        p.start_group    = Optional(r"\math" + one_of(self._fontnames)("font")) + "{"
        p.end_group      = Literal("}")

        p.delim          = one_of(self._delims)

        # Mutually recursive definitions.  (Minimizing the number of Forward
        # elements is important for speed.)
        p.auto_delim       = Forward()