I think this is an old note, everything seems to be documented

mtiller · mtiller · commit ce9f567dc9a8 · 2014-08-15T09:05:57.000-04:00
diff --git a/text/source/behavior/arrays/functions.rst b/text/source/behavior/arrays/functions.rst
@@ -193,8 +193,6 @@ would yield the vector:
 
     {1.0, 1.5, 2.0, 3.5, 3.0, 3.5, 4.0, 4.5, 5.0}
 
-.. todo:: Document these functions
-
 Conversion Functions
 ^^^^^^^^^^^^^^^^^^^^
 
