chore: add line break node

plugin/gomark/parser/line_break.go

@@ -0,0 +1,33 @@
+package parser
+
+import (
+	"github.com/usememos/memos/plugin/gomark/ast"
+	"github.com/usememos/memos/plugin/gomark/parser/tokenizer"
+)
+
+type LineBreakParser struct{}
+
+var defaultLineBreakParser = &LineBreakParser{}
+
+func NewLineBreakParser() *LineBreakParser {
+	return defaultLineBreakParser
+}
+
+func (*LineBreakParser) Match(tokens []*tokenizer.Token) (int, bool) {
+	if len(tokens) == 0 {
+		return 0, false
+	}
+	if tokens[0].Type != tokenizer.Newline {
+		return 0, false
+	}
+	return 1, true
+}
+
+func (p *LineBreakParser) Parse(tokens []*tokenizer.Token) ast.Node {
+	size, ok := p.Match(tokens)
+	if size == 0 || !ok {
+		return nil
+	}
+
+	return ast.NewLineBreak()
+}