feat: implement auto link parser

plugin/gomark/parser/auto_link.go

@@ -0,0 +1,50 @@
+package parser
+
+import (
+	"errors"
+
+	"github.com/usememos/memos/plugin/gomark/ast"
+	"github.com/usememos/memos/plugin/gomark/parser/tokenizer"
+)
+
+type AutoLinkParser struct{}
+
+func NewAutoLinkParser() *AutoLinkParser {
+	return &AutoLinkParser{}
+}
+
+func (*AutoLinkParser) Match(tokens []*tokenizer.Token) (int, bool) {
+	if len(tokens) < 3 {
+		return 0, false
+	}
+	if tokens[0].Type != tokenizer.LessThan {
+		return 0, false
+	}
+	urlTokens := []*tokenizer.Token{}
+	for _, token := range tokens[1:] {
+		if token.Type == tokenizer.Newline || token.Type == tokenizer.Space {
+			return 0, false
+		}
+		if token.Type == tokenizer.GreaterThan {
+			break
+		}
+		urlTokens = append(urlTokens, token)
+	}
+	if 2+len(urlTokens) > len(tokens) {
+		return 0, false
+	}
+
+	return 2 + len(urlTokens), true
+}
+
+func (p *AutoLinkParser) Parse(tokens []*tokenizer.Token) (ast.Node, error) {
+	size, ok := p.Match(tokens)
+	if size == 0 || !ok {
+		return nil, errors.New("not matched")
+	}
+
+	urlTokens := tokens[1 : size-1]
+	return &ast.AutoLink{
+		URL: tokenizer.Stringify(urlTokens),
+	}, nil
+}