Do not re-wrap align environments, and do not apply AsciiMath to LaTeX (autodetect).

Author: sangwinc

corsscripts/ascii/filters/010_latexwrap.js

@@ -8,6 +8,29 @@ import findtextindex from './findtextindex.js';
 //   col 3 – relation symbol and right-hand side
 // A \text{…} that is not \text{or/and/if} is pushed into a 4th column.
 export default function latexwrap(lines) {
+    // Do not attempt to wrap LaTeX which is already aligned.
+    const nonest = [
+        'align',
+        'flalign',
+        'alignat',
+        'xalignat',
+        'xxalignat',
+        'gather',
+        'multline',
+        'equation',
+        'split',
+        'subequations'
+        ];
+    const skipenv = nonest.flatMap(token => [`\\begin{${token}}`, `\\begin{${token}*}`]);
+    var skip = false;
+    for (let str of lines) {
+        if (findtextindex(str, skipenv) !== false) {
+            skip = true;
+        }
+    }
+    if (skip) {
+        return lines;
+    }
     const output = [`\\[\\begin{align*}`];
     for (let str of lines) {
         str = str.trim();

corsscripts/ascii/markdownitrules.js

@@ -22,11 +22,18 @@ export default function markdownitrules(mdit, options) {
     mdit.renderer.rules.code_inline = function(tokens, idx) {
         const code = tokens[idx].content;
         const inlineWrap = (s) => `\\(${s}\\)`;
+        if (isLaTeX(code)) {
+            return inlineWrap(code);
+        }
         return inlineWrap(window.AMparseMath(code, true));
     };
 
     mdit.renderer.rules.asciimath_block = function(tokens, idx) {
         const code = tokens[idx].content;
+        const blockWrap = (s) => `\\[${s}\\]`;
+        if (isLaTeX(code)) {
+            return blockWrap(code);
+        }
         return applyFilters(code, true);
     };
 
@@ -41,6 +48,24 @@ export default function markdownitrules(mdit, options) {
         return applyFilters(code, false);
     };
 
+    function isLaTeX(code) {
+        // Do not attempt to apply ASCIIMath to blocks which are already LaTeX.
+        const islatex = [
+            '^{',
+            '_{',
+            '\\left',
+            '\\right',
+            '\\begin',
+            ];
+        if (islatex.some(s => code.includes(s))) {
+            return true;
+        };
+        // Use of a general control code. 
+        // (Yes, this duplicates \left, \right, \begin above...)
+        const regex = /\\[a-zA-Z]+/;
+        return regex.test(code);
+        };
+
     function splitBlock(code) {
         return code.split(/\r?\n/).map(line => line.trim()).filter(line => line !== '');
     }