+
+
+void
+taint (SCM *)
+{
+ /*
+ nop.
+ */
+}
+
+/*
+ display stuff without using stack
+ */
+SCM
+display_list (SCM s)
+{
+ SCM p = scm_current_output_port();
+
+ scm_puts ("(", p);
+ for (; gh_pair_p(s); s =gh_cdr(s))
+ {
+ scm_display (gh_car(s), p);
+ scm_puts (" ", p);
+ }
+ scm_puts (")", p);
+ return SCM_UNSPECIFIED;
+}
+
+Slice
+int_list_to_slice (SCM l)
+{
+ Slice s;
+ s.set_empty ();
+ for (; gh_pair_p (l); l = gh_cdr (l))
+ {
+ if (gh_number_p (gh_car (l)))
+ s.add_point (gh_scm2int (gh_car (l)));
+ }
+
+ return s;
+}
+
+
+/*
+ Return I-th element, or last elt L. If I < 0, then we take the first
+ element.
+
+ PRE: length (L) > 0
+ */
+SCM
+robust_list_ref(int i, SCM l)
+{
+ while (i-- > 0 && gh_pair_p (gh_cdr(l)))
+ l = gh_cdr (l);
+
+ return gh_car(l);
+}
+
+
+
+Real
+robust_scm2double (SCM k, double x)
+{
+ if (gh_number_p (k))
+ x = gh_scm2double (k);
+ return x;
+}
+
+Interval
+robust_scm2interval (SCM k, Drul_array<Real> v)
+{
+ Interval i;
+ i[LEFT]= v[LEFT];
+ i[RIGHT]= v[RIGHT];
+ if (is_number_pair (k))
+ i = ly_scm2interval (k);
+ return i;
+}
+
+Drul_array<Real>
+robust_scm2drul (SCM k, Drul_array<Real> v)
+{
+ if (is_number_pair (k))
+ v = ly_scm2interval (k);
+ return v;
+}
+
+Offset
+robust_scm2offset (SCM k, Offset o)
+{
+ if (is_number_pair (k))
+ o = ly_scm2offset (k);
+
+ return o;
+}
+
+
+int
+robust_scm2int (SCM k, int o)
+{
+ if (scm_integer_p (k) == SCM_BOOL_T)
+ o = gh_scm2int (k);
+
+ return o;
+}
+
+
+SCM
+alist_to_hashq (SCM alist)
+{
+ int i = scm_ilength (alist);
+ if (i < 0)
+ return scm_make_vector (gh_int2scm (0), SCM_EOL);
+
+ SCM tab = scm_make_vector (gh_int2scm (i), SCM_EOL);
+ for (SCM s = alist; gh_pair_p (s); s = ly_cdr (s))
+ {
+ SCM pt = ly_cdar (s);
+ scm_hashq_set_x (tab, ly_caar (s), pt);
+ }
+ return tab;
+}