Like missing value, this is implemented as a class with no values. I've never found a use for it in communicating with a scriptable application, nor have I ever seen an application return it as a result. But I do sometimes use it in my own scripts, as a way of giving a variable or record item a value that signifies "No value has been assigned yet" without its being undefined. Examples have appeared in "The Run Handler" in Chapter 9 and "Record" in Chapter 13.


 set aPerson to {name:null, age:null, town:null} 

AppleScript. The Definitive Guide
AppleScript: The Definitive Guide, 2nd Edition
ISBN: 0596102119
EAN: 2147483647
Year: 2006
Pages: 267
Authors: Matt Neuburg

Similar book on Amazon © 2008-2017.
If you may any questions please contact us: