Do statement as "Applescript" in caller ?

[Serge Brami]

hello 
somebody knows what means the [caller] param in the command   Do  statement as "Applescript"  in caller
There is not any  example   in the livecode dictionnary 
Is it the name of the handler where  the command is in ? I have tried but doesnt work

I ask because statements as  :  do anything as Applescript  doesnt work on Livecode 6.6 and Maverick 
Any Idea ?

Thanks