--- a/scripts/special-matrix/vander.m
+++ b/scripts/special-matrix/vander.m
@@ -60,37 +60,36 @@
     print_usage ();
   endif
 
-  if (isvector (c))
-    retval = zeros (length (c), n, class (c));
-    ## avoiding many ^s appears to be faster for n >= 100.
-    d = 1;
-    c = c(:);
-    for i = n:-1:1
-      retval(:,i) = d;
-      d = c .* d;
-    endfor
-  else
-    error ("vander: argument must be a vector");
+  if (! isvector (c))
+    error ("vander: polynomial C must be a vector");
   endif
 
+  ## avoiding many ^s appears to be faster for n >= 100.
+  retval = zeros (length (c), n, class (c));
+  d = 1;
+  c = c(:);
+  for i = n:-1:1
+    retval(:,i) = d;
+    d .*= c;
+  endfor
+
 endfunction
 
+
 %!test
 %! c = [0,1,2,3];
 %! expect = [0,0,0,1; 1,1,1,1; 8,4,2,1; 27,9,3,1];
-%! result = vander(c);
-%! assert(expect, result);
+%! assert(vander (c), expect);
 
-%!assert((vander (1) == 1 && vander ([1, 2, 3]) == vander ([1; 2; 3])
-%! && vander ([1, 2, 3]) == [1, 1, 1; 4, 2, 1; 9, 3, 1]
-%! && vander ([1, 2, 3]*i) == [-1, i, 1; -4, 2i, 1; -9, 3i, 1]));
+%!assert (vander (1), 1)
+%!assert (vander ([1, 2, 3]), vander ([1; 2; 3]))
+%!assert (vander ([1, 2, 3]), [1, 1, 1; 4, 2, 1; 9, 3, 1])
+%!assert (vander ([1, 2, 3]*i), [-1, i, 1; -4, 2i, 1; -9, 3i, 1])
 
 %!assert(vander (2, 3), [4, 2, 1])
 %!assert(vander ([2, 3], 3), [4, 2, 1; 9, 3, 1])
 
-%!error vander ([1, 2; 3, 4]);
+%!error vander ();
+%!error vander (1, 2, 3);
+%!error <polynomial C must be a vector> vander ([1, 2; 3, 4]);
 
-%!error vander ();
-
-%!error vander (1, 2, 3);
-