chore: fix math block matcher

plugin/gomark/ast/ast.go

@@ -74,7 +74,7 @@ func (n *BaseNode) SetNextSibling(node Node) {
 
 func IsBlockNode(node Node) bool {
 	switch node.Type() {
-	case ParagraphNode, CodeBlockNode, HeadingNode, HorizontalRuleNode, BlockquoteNode, OrderedListNode, UnorderedListNode, TaskListNode:
+	case ParagraphNode, CodeBlockNode, HeadingNode, HorizontalRuleNode, BlockquoteNode, OrderedListNode, UnorderedListNode, TaskListNode, MathBlockNode:
 		return true
 	default:
 		return false

plugin/gomark/parser/math_block.go

@@ -18,7 +18,7 @@ func (*MathBlockParser) Match(tokens []*tokenizer.Token) (int, bool) {
 		return 0, false
 	}
 
-	if tokens[0].Type != tokenizer.DollarSign && tokens[1].Type != tokenizer.DollarSign && tokens[2].Type != tokenizer.Newline {
+	if tokens[0].Type != tokenizer.DollarSign || tokens[1].Type != tokenizer.DollarSign || tokens[2].Type != tokenizer.Newline {
 		return 0, false
 	}
 

plugin/gomark/parser/math_block_test.go

@@ -21,6 +21,12 @@ func TestMathBlockParser(t *testing.T) {
 				Content: "(1+x)^2",
 			},
 		},
+		{
+			text: "$$\na=3\n$$",
+			link: &ast.MathBlock{
+				Content: "a=3",
+			},
+		},
 	}
 	for _, test := range tests {
 		tokens := tokenizer.Tokenize(test.text)

plugin/gomark/parser/parser_test.go

@@ -197,6 +197,22 @@ func TestParser(t *testing.T) {
 				},
 			},
 		},
+		{
+			text: "\n\n",
+			nodes: []ast.Node{
+				&ast.LineBreak{},
+				&ast.LineBreak{},
+			},
+		},
+		{
+			text: "\n$$\na=3\n$$",
+			nodes: []ast.Node{
+				&ast.LineBreak{},
+				&ast.MathBlock{
+					Content: "a=3",
+				},
+			},
+		},
 	}
 
 	for _, test := range tests {