-/* inserts at front, removing dublicates */
-inline SCM ly_assoc_front_x (SCM alist, SCM key, SCM val)
-{
- return scm_acons (key, val, scm_assoc_remove_x (alist, key));
-}
+SCM ly_assoc_prepend_x (SCM alist, SCM key, SCM val);
+inline bool ly_is_fraction (SCM x) { return SCM_FRACTIONP(x) || scm_is_integer (x); }
+