feat(latex): latex in tui

ui-tui/src/__tests__/markdown.test.ts

@@ -61,6 +61,66 @@ describe('stripInlineMarkup', () => {
     expect(stripInlineMarkup('Yay ~! nice work ~!')).toBe('Yay ~! nice work ~!')
     expect(stripInlineMarkup('H~2~O and CO~2~')).toBe('H_2O and CO_2')
   })
+
+  it('strips inline math delimiters but keeps the formula text', () => {
+    expect(stripInlineMarkup('$\\mathbb{Z}$ is a ring')).toBe('\\mathbb{Z} is a ring')
+    expect(stripInlineMarkup('see \\(a + b\\) ok')).toBe('see a + b ok')
+  })
+})
+
+describe('INLINE_RE inline math', () => {
+  it('matches single-dollar math and beats emphasis at the same start', () => {
+    // Without math handling, `*b*` would have matched as italics and
+    // corrupted the formula. With math added to INLINE_RE, the leftmost
+    // match at column 0 (`$P=a*b*c$`) wins.
+    expect(matches('$P=a*b*c$')).toEqual(['$P=a*b*c$'])
+    expect(matches('see $\\mathbb{Z}$ here')).toEqual(['$\\mathbb{Z}$'])
+  })
+
+  it('does not match currency-style prose', () => {
+    expect(matches('it costs $5 and $10')).toEqual([])
+    expect(matches('paid $5')).toEqual([])
+  })
+
+  it('does not let inline math swallow a $$ display fence', () => {
+    // `$$x$$` is a display block, not two abutting inline-math spans.
+    expect(matches('$$x$$')).toEqual([])
+  })
+
+  it('matches \\(...\\) inline math', () => {
+    expect(matches('foo \\(x + y\\) bar')).toEqual(['\\(x + y\\)'])
+  })
+
+  it('does not corrupt subscripts/superscripts inside math', () => {
+    // `_n` and `^r` are markdown emphasis/superscript markers in prose, but
+    // inside a `$...$` span the entire formula is captured as a single
+    // inline-math token so the inner regexes never see those characters.
+    expect(matches('$P=a_n x^n + a_0$')).toEqual(['$P=a_n x^n + a_0$'])
+    expect(matches('$\\beta_1,\\dots,\\beta_r$')).toEqual(['$\\beta_1,\\dots,\\beta_r$'])
+  })
+
+  it('places math content in the correct capture group (regression: m[16] is bare URL)', () => {
+    // When `m[16]` was the bare URL group AND the inline-math `$...$`
+    // group simultaneously (because the bare URL pattern lacked its own
+    // capturing parens), MdInline rendered `$\\mathbb{R}$` as an
+    // underlined autolink instead of italic amber math. Lock down the
+    // numbering: math goes in m[17] / m[18], URLs go in m[16].
+    const url = [...'see https://example.com here'.matchAll(INLINE_RE)][0]!
+    const dollarMath = [...'$\\mathbb{R}$'.matchAll(INLINE_RE)][0]!
+    const parenMath = [...'\\(\\pi\\)'.matchAll(INLINE_RE)][0]!
+
+    expect(url[16]).toBe('https://example.com')
+    expect(url[17]).toBeUndefined()
+    expect(url[18]).toBeUndefined()
+
+    expect(dollarMath[16]).toBeUndefined()
+    expect(dollarMath[17]).toBe('\\mathbb{R}')
+    expect(dollarMath[18]).toBeUndefined()
+
+    expect(parenMath[16]).toBeUndefined()
+    expect(parenMath[17]).toBeUndefined()
+    expect(parenMath[18]).toBe('\\pi')
+  })
 })
 
 describe('protocol sentinels', () => {