Merge pull request #438 from saschabuehrle/fix/issue-370

fix: handle escaped dollar signs in inline math

Author: lepture

src/mistune/plugins/math.py

@@ -10,7 +10,7 @@
 __all__ = ["math", "math_in_quote", "math_in_list"]
 
 BLOCK_MATH_PATTERN = r"^ {0,3}\$\$[ \t]*\n(?P<math_text>[\s\S]+?)\n\$\$[ \t]*$"
-INLINE_MATH_PATTERN = r"\$(?!\s)(?P<math_text>.+?)(?!\s)\$"
+INLINE_MATH_PATTERN = r"\$(?!\s)(?P<math_text>(?:[^$\\]|\\.)+?)(?!\s)\$"
 
 
 def parse_block_math(block: "BlockParser", m: Match[str], state: "BlockState") -> int:

tests/fixtures/math.txt

@@ -55,3 +55,9 @@ with $a\neq b$ such that $f(a)=f(b)$.
 singleton set <span class="math">\(e_G\)</span>, because otherwise <span class="math">\(\exists a,b\in G\)</span>
 with <span class="math">\(a\neq b\)</span> such that <span class="math">\(f(a)=f(b)\)</span>.</p>
 ````````````````````````````````
+
+```````````````````````````````` example
+Escaped dollar sign in math: $x=\$$
+.
+<p>Escaped dollar sign in math: <span class="math">\(x=\$\)</span></p>
+````````````````````````````````