fix: Support MathML \oiint and \oiiint (#2461)

* fix: Support MathML \oiint and \oiiint

* Update direct input section of docs

docs/supported.md

@@ -339,7 +339,7 @@ Available functions include:
 | $\iiint$ `\iiint`| $\smallint$ `\smallint` | $\biguplus$ `\biguplus`  | $\bigcup$ `\bigcup`
 | $\oint$ `\oint`  | $\oiint$ `\oiint`       | $\oiiint$ `\oiiint`      | $\bigsqcup$ `\bigsqcup`
 
-Direct Input: $∫ ∬ ∭ ∮ ∏ ∐ ∑ ⋀ ⋁ ⋂ ⋃ ⨀ ⨁ ⨂ ⨄ ⨆$
+Direct Input: $∫ ∬ ∭ ∮ ∏ ∐ ∑ ⋀ ⋁ ⋂ ⋃ ⨀ ⨁ ⨂ ⨄ ⨆$ ∯ ∰
 
 ### Binary Operators
 

src/symbols.js

@@ -663,6 +663,8 @@ defineSymbol(math, main, op, "\u2a02", "\\bigotimes");
 defineSymbol(math, main, op, "\u2a01", "\\bigoplus");
 defineSymbol(math, main, op, "\u2a00", "\\bigodot");
 defineSymbol(math, main, op, "\u222e", "\\oint");
+defineSymbol(math, main, op, "\u222f", "\\oiint");
+defineSymbol(math, main, op, "\u2230", "\\oiiint");
 defineSymbol(math, main, op, "\u2a06", "\\bigsqcup");
 defineSymbol(math, main, op, "\u222b", "\\smallint");
 defineSymbol(text, main, inner, "\u2026", "\\textellipsis");

test/__snapshots__/mathml-spec.js.snap

@@ -688,6 +688,61 @@ exports[`A MathML builder should use <mpadded> for raisebox 1`] = `
 </math>
 `;
 
+exports[`A MathML builder should use <msupsub> for integrals 1`] = `
+<math xmlns="http://www.w3.org/1998/Math/MathML">
+  <semantics>
+    <mrow>
+      <mstyle scriptlevel="0"
+              displaystyle="true"
+      >
+        <msubsup>
+          <mo>
+            ∫
+          </mo>
+          <mi>
+            a
+          </mi>
+          <mi>
+            b
+          </mi>
+        </msubsup>
+        <mo>
+          +
+        </mo>
+        <msubsup>
+          <mo>
+            ∯
+          </mo>
+          <mi>
+            a
+          </mi>
+          <mi>
+            b
+          </mi>
+        </msubsup>
+        <mo>
+          +
+        </mo>
+        <msubsup>
+          <mo>
+            ∰
+          </mo>
+          <mi>
+            a
+          </mi>
+          <mi>
+            b
+          </mi>
+        </msubsup>
+      </mstyle>
+    </mrow>
+    <annotation encoding="application/x-tex">
+      \\displaystyle\\int_a^b + \\oiint_a^b + \\oiiint_a^b
+    </annotation>
+  </semantics>
+</math>
+`;
+
 exports[`A MathML builder should use <msupsub> for regular operators 1`] = `
 <math xmlns="http://www.w3.org/1998/Math/MathML">
   <semantics>

test/mathml-spec.js

@@ -44,6 +44,11 @@ describe("A MathML builder", function() {
         expect(getMathML("\\displaystyle\\sum_a^b")).toMatchSnapshot();
     });
 
+    it('should use <msupsub> for integrals', () => {
+        expect(getMathML("\\displaystyle\\int_a^b + " +
+            "\\oiint_a^b + \\oiiint_a^b")).toMatchSnapshot();
+    });
+
     it('should use <msupsub> for regular operators', () => {
         expect(getMathML("\\textstyle\\sum_a^b")).toMatchSnapshot();
     });