SCM ly_offset2scm (Offset);
Offset ly_scm2offset (SCM);
SCM ly_chain_assoc (SCM key, SCM achain);
-SCM ly_chain_assoc_get (SCM key, SCM achain, SCM dfault);
+SCM ly_chain_assoc_get (SCM key, SCM achain, SCM val);
SCM ly_assoc_cdr (SCM key, SCM alist);
SCM ly_assoc_get (SCM key, SCM alist, SCM def);
Interval ly_scm2interval (SCM);