Assigned function [Revelation On-Line Wiki]

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====== Assigned function  ======


 
==== Description ====
 
Tests if a variable has been assigned.  Returns the opposite values from [[unassigned|unassigned()]].
 
==== Syntax ====
 
//truefalse// = **Assigned**(//variable//)
 
==== Parameters ====
 
The Assigned function is used to determine whether a value has been assigned to a variable. You can avoid "variable not assigned a value" (VNAV) errors, by making sure that any variable you reference in your code has, at minimum, a null value.

Note:  A null value is different from an unassigned value.  A null value is a known, assigned value of%%''%% .  If a variable is unassigned it has an unknown value.

Note:  The [[unassigned|unassigned()]] function requires a function declaration.  The assigned() function does not require a function declaration.
 

 
==== Returns ====
 
True (1) if variable is assigned;  false (0) if variable is unassigned.
 
==== See Also ====
 
[[unassigned|unassigned()]]
 
==== Example ====
 
<code>
function RowExists(Table, Key)
$insert Logical
Exists = FALSE$
if assigned(Table) and assigned(Key) then
  open Table to Handle then
    read Row from Handle, Key then
      Exists = TRUE$
    end
  end
end
return Exists
 
**
**
</code>