Adding upstream version 0.3.3.upstream/0.3.3upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 126 insertions, 0 deletions

diff --git a/mdit_py_plugins/amsmath/__init__.py b/mdit_py_plugins/amsmath/__init__.py
new file mode 100644
index 0000000..0b367b5
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+++ b/mdit_py_plugins/amsmath/__init__.py
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+"""An extension to capture amsmath latex environments."""
+import re
+from typing import Callable, Optional
+
+from markdown_it import MarkdownIt
+from markdown_it.common.utils import escapeHtml
+from markdown_it.rules_block import StateBlock
+
+# Taken from amsmath version 2.1
+# http://anorien.csc.warwick.ac.uk/mirrors/CTAN/macros/latex/required/amsmath/amsldoc.pdf
+ENVIRONMENTS = [
+    # 3.2 single equation with an automatically gen-erated number
+    "equation",
+    # 3.3 variation equation, used for equations that don’t fit on a single line
+    "multline",
+    # 3.5 a group of consecutive equations when there is no alignment desired among them
+    "gather",
+    # 3.6 Used for two or more equations when vertical alignment is desired
+    "align",
+    # allows the horizontal space between equationsto be explicitly specified.
+    "alignat",
+    # stretches the space betweenthe equation columns to the maximum possible width
+    "flalign",
+    # 4.1 The pmatrix, bmatrix, Bmatrix, vmatrix and Vmatrix have (respectively)
+    # (),[],{},||,and ‖‖ delimiters built in.
+    "matrix",
+    "pmatrix",
+    "bmatrix",
+    "Bmatrix",
+    "vmatrix",
+    "Vmatrix",
+    # eqnarray is another math environment, it is not part of amsmath,
+    # and note that it is better to use align or equation+split instead
+    "eqnarray",
+]
+# 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")([\*]?)\}")
+
+
+def amsmath_plugin(md: MarkdownIt, *, renderer: Optional[Callable[[str], str]] = None):
+    """Parses TeX math equations, without any surrounding delimiters,
+    only for top-level `amsmath <https://ctan.org/pkg/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"]},
+    )
+
+    if renderer is None:
+        _renderer = lambda content: escapeHtml(content)
+    else:
+        _renderer = renderer
+
+    def render_amsmath_block(self, tokens, idx, options, env):
+        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):
+    match_open = RE_OPEN.match(string)
+    if not match_open:
+        return None
+    environment = match_open.group(1)
+    numbered = match_open.group(2)
+    match_close = re.search(
+        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):
+
+    # if it's indented more than 3 spaces, it should be a code block
+    if state.sCount[startLine] - state.blkIndent >= 4:
+        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}
+        token.map = [startLine, line]
+
+    return True