diff --git a/reserved.go b/reserved.go
new file mode 100644
index 0000000..75ebb10
--- /dev/null
+++ b/reserved.go
@@ -0,0 +1,12 @@
+package rfc2234
+
+// IsReserved returns true if value of 'r' matches 'reserved' as defined in IETF RFC-2234:
+//
+//	reserved    = gen-delims / sub-delims
+//	
+//	gen-delims  = ":" / "/" / "?" / "#" / "[" / "]" / "@"
+//	
+//	sub-delims  = "!" / "$" / "&" / "'" / "(" / ")" / "*" / "+" / "," / ";" / "="
+func IsReserved(r rune) bool {
+	return IsGenDelim(r) || IsSubDelim(r)
+}