Fix incorrect preference for multi-letter alpha over Roman

Author: aboks

README.md

@@ -165,7 +165,8 @@ Supported configuration options:
   </ol>
   ```
   Multi-letter alphabetic numerals can consist of at most 3 characters, which should be enough for a
-  typical list.
+  typical list. When a list starts with a numeral that can be both Roman or multi-letter alphabetic,
+  like "II", it is considered to be Roman.
 
 Versioning
 ----------

src/index.ts

@@ -149,7 +149,7 @@ function analyseMarker(state: StateBlock, startLine: number, endLine: number, pr
 			};
 		} else if (isCharCodeLowercaseAlpha(charCode)) {
 			const isValidAlpha = bulletChar.length === 1 || options.allowMultiLetter === true;
-			const preferRoman = ((previousMarker !== null && previousMarker.isRoman === true) || ((previousMarker === null || previousMarker.isAlpha === false) && bulletChar === "i"));
+			const preferRoman = ((previousMarker !== null && previousMarker.isRoman === true) || ((previousMarker === null || previousMarker.isAlpha === false) && (bulletChar === "i" || bulletChar.length > 1)));
 			const { parsedRomanNumber, isValidRoman } = analyzeRoman(bulletChar);
 
 			if (isValidRoman === true && (isValidAlpha === false || preferRoman === true)) {
@@ -174,7 +174,7 @@ function analyseMarker(state: StateBlock, startLine: number, endLine: number, pr
 			return null;
 		} else if (isCharCodeUppercaseAlpha(charCode)) {
 			const isValidAlpha = bulletChar.length === 1 || options.allowMultiLetter === true;
-			const preferRoman = ((previousMarker !== null && previousMarker.isRoman === true) || ((previousMarker === null || previousMarker.isAlpha === false) && bulletChar === "I"));
+			const preferRoman = ((previousMarker !== null && previousMarker.isRoman === true) || ((previousMarker === null || previousMarker.isAlpha === false) && (bulletChar === "I" || bulletChar.length > 1)));
 			const { parsedRomanNumber, isValidRoman } = analyzeRoman(bulletChar);
 
 			if (isValidRoman === true && (isValidAlpha === false || preferRoman === true)) {

test/index.ts

@@ -784,6 +784,42 @@ Ac) baz
 <p>Aa) foo
 Ab) bar
 Ac) baz</p>
+`;
+			await assertHTML(expectedHtml, markdown, {
+				allowMultiLetter: true,
+			});
+		});
+
+		it("prefers roman numerals over multi-letter alphabetic numerals", async () => {
+			const markdown = `
+II) foo
+III) bar
+IV) baz
+`;
+			const expectedHtml = `
+<ol type="I" start="2">
+  <li>foo</li>
+  <li>bar</li>
+  <li>baz</li>
+</ol>
+`;
+			await assertHTML(expectedHtml, markdown, {
+				allowMultiLetter: true,
+			});
+		});
+
+		it("prefers multi-letter alphabetic numerals over roman numerals when already in an alphabetic list", async () => {
+			const markdown = `
+IH) foo
+II) bar
+IJ) baz
+`;
+			const expectedHtml = `
+<ol type="A" start="242">
+  <li>foo</li>
+  <li>bar</li>
+  <li>baz</li>
+</ol>
 `;
 			await assertHTML(expectedHtml, markdown, {
 				allowMultiLetter: true,