Merge pull request #399 from lostenderman/fix-tex-backslash-extensions

Witiko · Jan 31, 2024 · fb24af4 · fb24af4
2 parents b113333 + 0ac80c5
commit fb24af4
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diff --git a/CHANGES.md b/CHANGES.md
@@ -31,6 +31,12 @@ Docker:
 
 - Uninstall the distribution Markdown package. (258a73d4)
 
+Fixes:
+
+- Make Pandoc syntax extensions `tex_single_backslash_math` and
+  `tex_double_backslash_math` robust against extra spaces at the beginning /
+  end of inline / display math. (#386, #399, contributed by @lostenderman)
+
 ## 3.3.0 (2023-12-30)
 
 Development:

diff --git a/markdown.dtx b/markdown.dtx
@@ -31603,8 +31603,16 @@ M.extensions.tex_math = function(tex_math_dollars,
         return (starter * Cs(p * (p - ender)^0) * ender)
       end
 
+      local function strip_preceding_whitespaces(str)
+        return str:gsub("^%s*(.-)$", "%1")
+      end
+
       local allowed_before_closing = B( parsers.backslash * parsers.any
-                                      + parsers.any * (parsers.nonspacechar - parsers.backslash))
+                                      + parsers.any * (parsers.any - parsers.backslash))
+
+      local allowed_before_closing_no_space = B( parsers.backslash * parsers.any
+                                               + parsers.any * (parsers.nonspacechar - parsers.backslash))
+
 %    \end{macrocode}
 % \begin{markdown}
 %
@@ -31621,7 +31629,7 @@ M.extensions.tex_math = function(tex_math_dollars,
       local inline_math_opening_dollars = parsers.dollar
                                         * #(parsers.nonspacechar)
 
-      local inline_math_closing_dollars = allowed_before_closing
+      local inline_math_closing_dollars = allowed_before_closing_no_space
                                         * parsers.dollar
                                         * -#(parsers.digit)
 
@@ -31660,29 +31668,32 @@ M.extensions.tex_math = function(tex_math_dollars,
       local inline_math_opening_double  = parsers.backslash
                                         * parsers.backslash
                                         * parsers.lparent
-                                        * #(parsers.nonspacechar)
 
       local inline_math_closing_double  = allowed_before_closing
+                                        * parsers.spacechar^0
                                         * parsers.backslash
                                         * parsers.backslash
                                         * parsers.rparent
 
       local inline_math_double  = between(Cs( backslash_math_content),
                                           inline_math_opening_double,
                                           inline_math_closing_double)
+                                / strip_preceding_whitespaces
 
       local display_math_opening_double = parsers.backslash
                                         * parsers.backslash
                                         * parsers.lbracket
 
       local display_math_closing_double = allowed_before_closing
+                                        * parsers.spacechar^0
                                         * parsers.backslash
                                         * parsers.backslash
                                         * parsers.rbracket
 
       local display_math_double = between(Cs( backslash_math_content),
                                           display_math_opening_double,
                                           display_math_closing_double)
+                                / strip_preceding_whitespaces
 %    \end{macrocode}
 % \begin{markdown}
 %
@@ -31693,26 +31704,29 @@ M.extensions.tex_math = function(tex_math_dollars,
 %  \begin{macrocode}
       local inline_math_opening_single  = parsers.backslash
                                         * parsers.lparent
-                                        * #(parsers.nonspacechar)
 
       local inline_math_closing_single  = allowed_before_closing
+                                        * parsers.spacechar^0
                                         * parsers.backslash
                                         * parsers.rparent
 
       local inline_math_single  = between(Cs( backslash_math_content),
                                           inline_math_opening_single,
                                           inline_math_closing_single)
+                                / strip_preceding_whitespaces
 
       local display_math_opening_single = parsers.backslash
                                         * parsers.lbracket
 
       local display_math_closing_single = allowed_before_closing
+                                        * parsers.spacechar^0
                                         * parsers.backslash
                                         * parsers.rbracket
 
       local display_math_single = between(Cs( backslash_math_content),
                                           display_math_opening_single,
                                           display_math_closing_single)
+                                / strip_preceding_whitespaces
 
       local display_math = parsers.fail
 

diff --git a/tests/testfiles/lunamark-markdown/tex-math-double-backslash.test b/tests/testfiles/lunamark-markdown/tex-math-double-backslash.test
@@ -31,17 +31,29 @@ c\\)
 
 c\\]
 
-No spaces are allowed at the beginning or the end of inline math:
-
-\\( \infty \\)
-
 Escaped spaces are allowed at the beginning or the end of inline math:
 
 \\(\ \\)
 
 The following is not inline math:
 
 \\\(a\\\)
+
+Whitespace characters are allowed at the beginning or the end of inline math or display math:
+
+\\( 1+2=3 \\)
+
+\\(	1+2=3	\\)
+
+\\[ 1+2=3 \\]
+
+\\[	1+2=3	\\]
+
+Whitespace-only content is allowed:
+
+\\( \\)
+
+\\[ \\]
 >>>
 BEGIN document
 codeSpan: texMathDoubleBackslash
@@ -68,14 +80,23 @@ paragraphSeparator
 backslash
 paragraphSeparator
 paragraphSeparator
-backslash
+inlineMath: \ 
+paragraphSeparator
+paragraphSeparator
 backslash
 backslash
 paragraphSeparator
 paragraphSeparator
-inlineMath: \ 
+inlineMath: 1+2=3
 paragraphSeparator
+inlineMath: 1+2=3
 paragraphSeparator
-backslash
-backslash
+displayMath: 1+2=3
+paragraphSeparator
+displayMath: 1+2=3
+paragraphSeparator
+paragraphSeparator
+inlineMath: 
+paragraphSeparator
+displayMath: 
 END document
diff --git a/tests/testfiles/lunamark-markdown/tex-math-single-backslash.test b/tests/testfiles/lunamark-markdown/tex-math-single-backslash.test
@@ -31,17 +31,29 @@ c\)
 
 c\]
 
-No spaces are allowed at the beginning or the end of inline math:
-
-\( \infty \)
-
 Escaped spaces are allowed at the beginning or the end of inline math:
 
 \(\ \)
 
 The following is inline math with two backslashes:
 
 \\\(a\\\)
+
+Whitespace characters are allowed at the beginning or the end of inline math or display math:
+
+\( 1+2=3 \)
+
+\(	1+2=3	\)
+
+\[ 1+2=3 \]
+
+\[	1+2=3	\]
+
+Whitespace-only content is allowed:
+
+\( \)
+
+\[ \]
 >>>
 BEGIN document
 codeSpan: texMathSingleBackslash
@@ -60,12 +72,23 @@ paragraphSeparator
 paragraphSeparator
 paragraphSeparator
 paragraphSeparator
-backslash
-paragraphSeparator
-paragraphSeparator
 inlineMath: \ 
 paragraphSeparator
 paragraphSeparator
 backslash
 inlineMath: a\\
+paragraphSeparator
+paragraphSeparator
+inlineMath: 1+2=3
+paragraphSeparator
+inlineMath: 1+2=3
+paragraphSeparator
+displayMath: 1+2=3
+paragraphSeparator
+displayMath: 1+2=3
+paragraphSeparator
+paragraphSeparator
+inlineMath: 
+paragraphSeparator
+displayMath: 
 END document