Add multiline math syntax

Co-authored-by: syuilo <syuilotan@yahoo.co.jp>

src/mfm/html.ts

@@ -87,7 +87,13 @@ export default (tokens: MfmForest, mentionedRemoteUsers: INote['mentionedRemoteU
 			return el;
 		},
 
-		math(token) {
+		mathInline(token) {
+			const el = doc.createElement('code');
+			el.textContent = token.node.props.formula;
+			return el;
+		},
+
+		mathBlock(token) {
 			const el = doc.createElement('code');
 			el.textContent = token.node.props.formula;
 			return el;

src/mfm/parser.ts

@@ -103,7 +103,8 @@ const mfm = P.createLanguage({
 		r.blockCode,
 		r.inlineCode,
 		r.quote,
-		r.math,
+		r.mathInline,
+		r.mathBlock,
 		r.search,
 		r.title,
 		r.center,
@@ -121,7 +122,7 @@ const mfm = P.createLanguage({
 			r.mention,
 			r.hashtag,
 			r.emoji,
-			r.math,
+			r.mathInline,
 			r.text
 		).atLeast(1).tryParse(x), {})),
 	//#endregion
@@ -135,7 +136,7 @@ const mfm = P.createLanguage({
 			r.mention,
 			r.hashtag,
 			r.emoji,
-			r.math,
+			r.mathInline,
 			r.text
 		).atLeast(1).tryParse(x), {})),
 	//#endregion
@@ -180,7 +181,7 @@ const mfm = P.createLanguage({
 			r.mention,
 			r.hashtag,
 			r.emoji,
-			r.math,
+			r.mathInline,
 			r.url,
 			r.link,
 			r.text
@@ -274,10 +275,16 @@ const mfm = P.createLanguage({
 		}),
 	//#endregion
 
-	//#region Math
-	math: r =>
+	//#region Math (inline)
+	mathInline: r =>
 		P.regexp(/\\\((.+?)\\\)/, 1)
-		.map(x => createLeaf('math', { formula: x })),
+		.map(x => createLeaf('mathInline', { formula: x })),
+	//#endregion
+
+	//#region Math (block)
+	mathBlock: r =>
+		P.regexp(/\\\[([\s\S]+?)\\\]/, 1)
+		.map(x => createLeaf('mathBlock', { formula: x.trim() })),
 	//#endregion
 
 	//#region Mention
@@ -311,7 +318,7 @@ const mfm = P.createLanguage({
 			r.emoji,
 			r.url,
 			r.link,
-			r.math,
+			r.mathInline,
 			r.text
 		).atLeast(1).tryParse(x), {})),
 	//#endregion