updates

frontmatter/runes.go

@@ -0,0 +1,58 @@
+package frontmatter
+
+import (
+	"bytes"
+	"errors"
+	"strings"
+)
+
+// HasRune checks if the file has the frontmatter rune
+func HasRune(file []byte) bool {
+	return strings.HasPrefix(string(file), "---") ||
+		strings.HasPrefix(string(file), "+++") ||
+		strings.HasPrefix(string(file), "{")
+}
+
+// AppendRune appends the frontmatter rune to a file
+func AppendRune(frontmatter []byte, mark rune) []byte {
+	frontmatter = bytes.TrimSpace(frontmatter)
+
+	switch mark {
+	case '-':
+		return []byte("---\n" + string(frontmatter) + "\n---")
+	case '+':
+		return []byte("+++\n" + string(frontmatter) + "\n+++")
+	case '{':
+		return []byte("{\n" + string(frontmatter) + "\n}")
+	}
+
+	return frontmatter
+}
+
+// RuneToStringFormat converts the rune to a string with the format
+func RuneToStringFormat(mark rune) (string, error) {
+	switch mark {
+	case '-':
+		return "yaml", nil
+	case '+':
+		return "toml", nil
+	case '{', '}':
+		return "json", nil
+	default:
+		return "", errors.New("Unsupported format type")
+	}
+}
+
+// StringFormatToRune converts the format name to its rune
+func StringFormatToRune(format string) (rune, error) {
+	switch format {
+	case "yaml":
+		return '-', nil
+	case "toml":
+		return '+', nil
+	case "json":
+		return '{', nil
+	default:
+		return '0', errors.New("Unsupported format type")
+	}
+}