/// Callback executed by the Lua syntax() function.
///
/// \param syntax_version The syntax format version as provided by the
/// configuration file in the call to syntax().
void
syntax_callback(const int syntax_version)
{
if (_syntax_called)
throw syntax_error("syntax() can only be called once");
_syntax_called = true;
// Allow the parser caller to populate the tree with its own schema
// depending on the format/version combination.
_parent->setup(_tree, syntax_version);
// Export the config module to the Lua state so that all global variable
// accesses are redirected to the configuration tree.
config::redirect(_state, _tree);
}
