quoteのネスト制限を追加 (#91)

* refactor quote

* add nesting limit test for quote

* nesting limit for quote

src/internal/parser.pegjs

@@ -77,7 +77,7 @@
 
 	// nesting control
 
-	const nestLimit = options.nestLimit || 20;
+	const nestLimit = (options.nestLimit != null ? options.nestLimit : 20);
 	let depth = 0;
 	function enterNest() {
 		if (depth + 1 > nestLimit) {
@@ -166,25 +166,32 @@ plain
 // block: quote
 
 quote
-	= &(BEGIN ">") q:quoteInner LF? { return q; }
+	= &(BEGIN ">") &{ return (depth + 1 <= nestLimit); } @quoteInner LF?
 
 quoteInner
 	= head:(quoteLine / quoteEmptyLine) tails:(quoteLine / quoteEmptyLine)+
 {
+	depth++;
 	const children = applyParser([head, ...tails].join('\n'), 'fullParser');
+	depth--;
 	return QUOTE(children);
 }
 	/ line:quoteLine
 {
+	depth++;
 	const children = applyParser(line, 'fullParser');
+	depth--;
 	return QUOTE(children);
 }
 
 quoteLine
-	= BEGIN ">" _? text:$CHAR+ END { return text; }
+	= BEGIN ">" _? @$CHAR+ END
 
 quoteEmptyLine
-	= BEGIN ">" _? END { return ''; }
+	= BEGIN ">" _? END
+{
+	return '';
+}
 
 // block: search
 

test/parser.ts

@@ -1128,6 +1128,36 @@ hoge`;
 	});
 
 	describe('nesting limit', () => {
+		describe('quote', () => {
+			it('basic', () => {
+				const input = '>>> abc';
+				const output = [
+					QUOTE([
+						QUOTE([
+							TEXT('> abc'),
+						]),
+					]),
+				];
+				assert.deepStrictEqual(mfm.parse(input, { nestLimit: 2 }), output);
+			});
+
+			it('basic 2', () => {
+				const input = '>> **abc**';
+				const output = [
+					QUOTE([
+						QUOTE([
+							TEXT('*'),
+							ITALIC([
+								TEXT('abc'),
+							]),
+							TEXT('*'),
+						]),
+					]),
+				];
+				assert.deepStrictEqual(mfm.parse(input, { nestLimit: 2 }), output);
+			});
+		});
+
 		it('big', () => {
 			const input = '<b><b>***abc***</b></b>';
 			const output = [