Newbie question - how to check for a varible

[J. Landman Gay]

Stephen Cox wrote:
> Wait. I don't get this. You saying that checking if an unused variable is
> empty returns false? Does revolution put some data in a variable when
> created? 

Sort of, but only in specific cases, which is mostly a side-effect of 
how friendly Rev's interpreter is and how it deals with strings. (The 
discussion about quoted field names shows how flexible Rev is with 
strings.) If a variable is not specifically created with a value, the 
value of the variable is the variable's name itself.

This creates a variable without assigning it any value:

on mouseup
  put (var = empty) && "Var = " & var
end mouseup

You get: false var = var

But this assigns a value and gives what you'd expect:

on mouseUp
  put empty into var
  put (var = empty) && "Var = " & var
end mouseUp

Gives: true var =

-- 
Jacqueline Landman Gay         |     jacque at hyperactivesw.com
HyperActive Software           |     http://www.hyperactivesw.com