Referential data types may need to be declared.

And other small fixes.

doc/tut1.txt

@@ -163,7 +163,6 @@ Another option is to use the `discard`_ statement together with
         yes("May I ask a pointless question?") """
 
 
-
 Numbers
 -------
 
@@ -606,9 +605,11 @@ the exit.
   echo sumTillNegative(3, 4 , -1 , 6) # echos 7
 
 The ``result`` variable is already implicitly declared at the start of the 
-function and initialised with the type's default value, so declaring it again 
-with 'var return', for example, would shadow it with a normal variable of the
-same name.
+function, so declaring it again with 'var result', for example, would shadow it
+with a normal variable of the same name. The result variable is also already
+initialised with the type's default value. Note that referential data types will
+be ``nil`` at the start of the procedure, and thus may require manual
+initialisation.
 
       
 Parameters