- (once-only (x . xs) xpr . xprs)syntax
to be used in a macro-body to avoid side-effects. The arguments x . xs are only evaluated once. once-only must be used for-syntax in explicit or implicit renaming macros.
to be used in a macro-body to avoid side-effects. The arguments x . xs are only evaluated once. once-only must be used for-syntax in explicit or implicit renaming macros.