Source code for mdit_py_plugins.amsmath

"""An extension to capture amsmath latex environments."""
from __future__ import annotations

import re
from typing import TYPE_CHECKING, Callable, Optional, Sequence

from markdown_it import MarkdownIt
from markdown_it.common.utils import escapeHtml
from markdown_it.rules_block import StateBlock

from mdit_py_plugins.utils import is_code_block

    from markdown_it.renderer import RendererProtocol
    from markdown_it.token import Token
    from markdown_it.utils import EnvType, OptionsDict

# Taken from amsmath version 2.1
    # 3.2 single equation with an automatically gen-erated number
    # 3.3 variation equation, used for equations that dont fit on a single line
    # 3.5 a group of consecutive equations when there is no alignment desired among them
    # 3.6 Used for two or more equations when vertical alignment is desired
    # allows the horizontal space between equationsto be explicitly specified.
    # stretches the space betweenthe equation columns to the maximum possible width
    # 4.1 The pmatrix, bmatrix, Bmatrix, vmatrix and Vmatrix have (respectively)
    # (),[],{},||,and ‖‖ delimiters built in.
    # eqnarray is another math environment, it is not part of amsmath,
    # and note that it is better to use align or equation+split instead
# other "non-top-level" environments:

# 3.4 the split environment is for single equations that are too long to fit on one line
# and hence must be split into multiple lines,
# it is intended for use only inside some other displayed equation structure,
# usually an equation, align, or gather environment

# 3.7 variants gathered, aligned,and alignedat are provided
# whose total width is the actual width of the contents;
# thus they can be used as a component in a containing expression

RE_OPEN = re.compile(r"\\begin\{(" + "|".join(ENVIRONMENTS) + r")([\*]?)\}")

[docs]def amsmath_plugin( md: MarkdownIt, *, renderer: Optional[Callable[[str], str]] = None ) -> None: """Parses TeX math equations, without any surrounding delimiters, only for top-level `amsmath <>`__ environments: .. code-block:: latex \\begin{gather*} a_1=b_1+c_1\\\\ a_2=b_2+c_2-d_2+e_2 \\end{gather*} :param renderer: Function to render content, by default escapes HTML """ md.block.ruler.before( "blockquote", "amsmath", amsmath_block, {"alt": ["paragraph", "reference", "blockquote", "list", "footnote_def"]}, ) _renderer = (lambda content: escapeHtml(content)) if renderer is None else renderer def render_amsmath_block( self: RendererProtocol, tokens: Sequence[Token], idx: int, options: OptionsDict, env: EnvType, ) -> str: content = _renderer(str(tokens[idx].content)) return f'<div class="math amsmath">\n{content}\n</div>\n' md.add_render_rule("amsmath", render_amsmath_block)
def match_environment(string: str) -> None | tuple[str, str, int]: match_open = RE_OPEN.match(string) if not match_open: return None environment = numbered = match_close = r"\\end\{" + environment + numbered.replace("*", r"\*") + "\\}", string ) if not match_close: return None return (environment, numbered, match_close.end()) def amsmath_block( state: StateBlock, startLine: int, endLine: int, silent: bool ) -> bool: if is_code_block(state, startLine): return False begin = state.bMarks[startLine] + state.tShift[startLine] outcome = match_environment(state.src[begin:]) if not outcome: return False environment, numbered, endpos = outcome endpos += begin line = startLine while line < endLine: if endpos >= state.bMarks[line] and endpos <= state.eMarks[line]: # line for end of block math found ... state.line = line + 1 break line += 1 if not silent: token = state.push("amsmath", "math", 0) token.block = True token.content = state.src[begin:endpos] token.meta = {"environment": environment, "numbered": numbered} = [startLine, line] return True