don't replace mbox when used as intended in LaTeX

compiler/src/pre-parse/__test__/convert-block-tex.test.ts

@@ -41,6 +41,33 @@ describe('convertNewPageToDirective', () => {
     expect(ignoreWhitespace(md)).toBe(ignoreWhitespace(expected));
   });
 
+  it('should reformat a \\mbox{ } to pagebreak directive', async () => {
+    const { md } = await testProcessor(`
+      \\mbox{ }
+    `);
+
+    const expected = unindentStringAndTrim(`
+      ::pagebreak
+    `);
+
+    expect(ignoreWhitespace(md)).toBe(ignoreWhitespace(expected));
+  });
+
+  it('should NOT reformat a \\mbox{x} to pagebreak directive', async () => {
+    const { md } = await testProcessor(String.raw`
+      \begin{equation}
+      \mathrm{sign}(x)=
+      \begin{cases}
+      1  & \mbox{if } $x>0$\\
+      0  & \mbox{if } $x=0$\\
+      -1 & \mbox{if } $x<0$\\
+      \end{cases}
+      \end{equation}
+    `);
+
+    expect(md.includes('::pagebreak')).toBe(false);
+  });
+
   it('should be idempotent', async () => {
     const { md } = await testProcessor(`
       \\newpage

compiler/src/pre-parse/convert-block-tex.ts

@@ -1,8 +1,23 @@
-const blockList = ['\\newpage', '\\pagebreak', '\\mbox'];
+const blockList = ['\\newpage', '\\pagebreak'];
 
 export function convertNewPageToDirective(contents: string) {
   return contents
     .split('\n')
     .map((a) => (blockList.some((b) => a.includes(b)) ? '::pagebreak' : a))
     .join('\n');
 }
+
+export function convertEmptyMBoxToDirective(contents: string) {
+  return contents
+    .split('\n')
+    .map((line) => {
+      if (
+        line.includes('\\mbox') &&
+        line.replace('{', '').replace('}', '').trim() === '\\mbox'
+      ) {
+        return '::pagebreak';
+      }
+      return line;
+    })
+    .join('\n');
+}

compiler/src/pre-parse/index.ts

@@ -1,7 +1,10 @@
 import { VFile } from 'vfile';
 
 import { allowNoWhitespaceBeforeHeading } from './allow-no-whitespace-before-heading';
-import { convertNewPageToDirective } from './convert-block-tex';
+import {
+  convertEmptyMBoxToDirective,
+  convertNewPageToDirective,
+} from './convert-block-tex';
 import { convertTextBfToMd, convertUrlToMd } from './convert-inline-tex';
 import { convertMacroToDirective } from './convert-macro-to-directive';
 import { reformatPandocSimpleTables } from './reformat-pandoc-simple-tables';
@@ -21,6 +24,7 @@ export function preParsePhase(file: VFile) {
   result = convertTextBfToMd(result);
   result = convertUrlToMd(result);
   result = convertNewPageToDirective(result);
+  result = convertEmptyMBoxToDirective(result);
   result = reformatPandocSimpleTables(result);
   file.contents = result;
   return file;