SCM ly_assoc_get (SCM key, SCM alist, SCM default_value, SCM strict_checking = SCM_BOOL_F);
Interval ly_scm2interval (SCM);
Drul_array<Real> ly_scm2realdrul (SCM);
SCM ly_assoc_get (SCM key, SCM alist, SCM default_value, SCM strict_checking = SCM_BOOL_F);
Interval ly_scm2interval (SCM);
Drul_array<Real> ly_scm2realdrul (SCM);