diff --git a/arrays.scad b/arrays.scad
index 5068d3b..5154407 100644
--- a/arrays.scad
+++ b/arrays.scad
@@ -66,8 +66,8 @@ function select(list, start, end=undef) =
                 list[ (start%l+l)%l ]
             :   assert( is_list(start) || is_range(start), "Invalid start parameter")
                 [for (i=start) list[ (i%l+l)%l ] ]
-        :   assert(is_num(start), "Invalid start parameter.")
-            assert(is_num(end), "Invalid end parameter.")
+        :   assert(is_finite(start), "Invalid start parameter.")
+            assert(is_finite(end), "Invalid end parameter.")
             let( s = (start%l+l)%l, e = (end%l+l)%l )
             (s <= e)? [for (i = [s:1:e]) list[i]]
             :   concat([for (i = [s:1:l-1]) list[i]], [for (i = [0:1:e]) list[i]]) ;
diff --git a/math.scad b/math.scad
index 3ff62d7..55e662b 100644
--- a/math.scad
+++ b/math.scad
@@ -240,7 +240,7 @@ function atanh(x) =
 //   quant([9,10,10.4,10.5,11,12],3);      // Returns: [9,9,9,12,12,12]
 //   quant([[9,10,10.4],[10.5,11,12]],3);  // Returns: [[9,9,9],[12,12,12]]
 function quant(x,y) =
-    assert(is_finite(y) && !approx(y,0,eps=1e-24), "The multiple must be a non zero integer.")
+    assert(is_finite(y) && !approx(y,0,eps=1e-24), "The multiple must be a non zero number.")
     is_list(x)
     ?   [for (v=x) quant(v,y)]
     :   assert( is_finite(x), "The input to quantize must be a number or a list of numbers.")
@@ -272,7 +272,7 @@ function quant(x,y) =
 //   quantdn([9,10,10.4,10.5,11,12],3);      // Returns: [9,9,9,9,9,12]
 //   quantdn([[9,10,10.4],[10.5,11,12]],3);  // Returns: [[9,9,9],[9,9,12]]
 function quantdn(x,y) =
-    assert(is_finite(y) && !approx(y,0,eps=1e-24), "The multiple must be a non zero integer.")
+    assert(is_finite(y) && !approx(y,0,eps=1e-24), "The multiple must be a non zero number.")
     is_list(x)
     ?    [for (v=x) quantdn(v,y)]
     :    assert( is_finite(x), "The input to quantize must be a number or a list of numbers.")
@@ -304,7 +304,7 @@ function quantdn(x,y) =
 //   quantup([9,10,10.4,10.5,11,12],3);      // Returns: [9,12,12,12,12,12]
 //   quantup([[9,10,10.4],[10.5,11,12]],3);  // Returns: [[9,12,12],[12,12,12]]
 function quantup(x,y) =
-    assert(is_finite(y) && !approx(y,0,eps=1e-24), "The multiple must be a non zero integer.")
+    assert(is_finite(y) && !approx(y,0,eps=1e-24), "The multiple must be a non zero number.")
     is_list(x)
     ?    [for (v=x) quantup(v,y)]
     :    assert( is_finite(x), "The input to quantize must be a number or a list of numbers.")
diff --git a/vectors.scad b/vectors.scad
index 51f4735..80909b2 100644
--- a/vectors.scad
+++ b/vectors.scad
@@ -19,6 +19,8 @@
 // Arguments:
 //   v = The value to test to see if it is a vector.
 //   length = If given, make sure the vector is `length` items long.
+//   zero = If false, require that the length of the vector is not approximately zero.  If true, require the length of the vector to be approximately zero-length.  Default: `undef` (don't check vector length.)
+//   eps = The minimum vector length that is considered non-zero.  Default: `EPSILON` (`1e-9`)
 // Example:
 //   is_vector(4);                          // Returns false
 //   is_vector([4,true,false]);             // Returns false
diff --git a/version.scad b/version.scad
index b6ba49c..483c726 100644
--- a/version.scad
+++ b/version.scad
@@ -8,7 +8,7 @@
 //////////////////////////////////////////////////////////////////////
 
 
-BOSL_VERSION = [2,0,399];
+BOSL_VERSION = [2,0,400];
 
 
 // Section: BOSL Library Version Functions