string: add a templated transform comparator

string.hpp

@@ -339,11 +339,21 @@ namespace cruft::string {
                     return false;
             }
 
-
             if (a_cursor == a.end () && b_cursor != b.end ())
                 return true;
+
             return false;
         }
+
+        template <typename A, typename B>
+        requires (!std::is_same_v<A,B>)
+        bool operator() (A &&a, B &&b) const noexcept
+        {
+            return (*this) (
+                std::string_view (a),
+                std::string_view (b)
+            );
+        }
     };