very basic version of usql

usql/exception.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#include "lexer.h"
+
+#include <string>
+
+namespace usql {
+
+class Exception : public std::exception {
+private:
+    std::string cause;
+
+public:
+    Exception(const std::string &msg);
+
+    const char *what() const noexcept;
+};
+
+}