feat(gomark): add bold parser (#1724)

plugin/gomark/parser/bold.go

@@ -0,0 +1,46 @@
+package parser
+
+import (
+	"github.com/usememos/memos/plugin/gomark/parser/tokenizer"
+)
+
+type BoldParser struct {
+	ContentTokens []*tokenizer.Token
+}
+
+func NewBoldParser() *BoldParser {
+	return &BoldParser{}
+}
+
+func (*BoldParser) Match(tokens []*tokenizer.Token) *BoldParser {
+	if len(tokens) < 5 {
+		return nil
+	}
+
+	prefixTokens := tokens[:2]
+	if len(prefixTokens) != 2 || prefixTokens[0].Type != prefixTokens[1].Type {
+		return nil
+	}
+	prefixTokenType := prefixTokens[0].Type
+
+	contentTokens := []*tokenizer.Token{}
+	cursor := 2
+	for ; cursor < len(tokens)-1; cursor++ {
+		token, nextToken := tokens[cursor], tokens[cursor+1]
+
+		if token.Type == tokenizer.Newline || nextToken.Type == tokenizer.Newline {
+			break
+		}
+		if token.Type == prefixTokenType && nextToken.Type == prefixTokenType {
+			break
+		}
+		contentTokens = append(contentTokens, token)
+	}
+	if cursor != len(tokens)-2 {
+		return nil
+	}
+
+	return &BoldParser{
+		ContentTokens: contentTokens,
+	}
+}