Implement throw_on_error functionality, rename some template parameters

include/ss/exception.hpp

@@ -0,0 +1,30 @@
+#pragma once
+#include <exception>
+#include <string>
+
+namespace ss {
+
+////////////////
+// exception
+////////////////
+
+class exception : public std::exception {
+    std::string msg_;
+
+public:
+    exception(const std::string& msg): msg_{msg} {
+    }
+
+    virtual char const* what() const noexcept {
+        return msg_.c_str();
+    }
+};
+
+template <bool throw_on_error>
+void throw_if_throw_on_error(const std::string& msg) {
+    if constexpr (throw_on_error) {
+        throw ss::exception(msg);
+    }
+}
+
+} /* ss */