Drul_array<bool> robust_scm2booldrul (SCM, Drul_array<bool>);
Interval robust_scm2interval (SCM, Drul_array<Real>);
Offset robust_scm2offset (SCM, Offset);
-string robust_scm2string (SCM, string);
SCM ly_quote_scm (SCM s);
bool type_check_assignment (SCM val, SCM sym, SCM type_symbol);
SCM ly_alist_vals (SCM alist);
SCM ly_hash2alist (SCM tab);
-SCM ly_hash_table_keys (SCM tab);
+
int procedure_arity (SCM);
/* inserts at front, removing dublicates */