Ar an séú lá déag de mí Eanair, scríobh Jerry James: Some suggestions to try, reverse the sense of the test, like so: if (NILP (s->tail)) s->head = read0 (readcharfun); else XCDR (s->tail) = read0 (readcharfun); Introduce a temporary variable, like so: else { Lisp_Object stale = s->tail; if (!NILP (stale)) XCDR (s->tail) = read0 (readcharfun); else s->head = read0 (readcharfun); Add some always-true code to the condition, where it’s not evident to the compiler that it’s always true, so it can’t simplify: if (Vmost_positive_fixnum != Vmost_negative_fixnum && !NILP (s->tail)) XCDR (s->tail) = read0 (readcharfun); else s->head = read0 (readcharfun); -- ‘Iodine deficiency was endemic in parts of the UK until, through what has been described as “an unplanned and accidental public health triumph”, iodine was added to cattle feed to improve milk production in the 1930s.’ (EN Pearce, Lancet, June 2011) _______________________________________________ XEmacs-Beta mailing list XEmacs-Beta(a)xemacs.org http://lists.xemacs.org/mailman/listinfo/xemacs-beta