User Guide

252 Chapter 12: Methods
callAncestor
Usage
callAncestor handlerName, script, {args...}
Description
Command; sends a message to a child object’s ancestor script.
Ancestors can, in turn, have their own ancestors.
When you use
callAncestor, the name of the handler can be a variable, and you can explicitly
bypass the handlers in the primary script and go directly to the ancestor script.
Parameters
symHandlerName
Required. A symbol that specifies the handler to activate.
scriptInstance Required. A reference to the script or list of scripts that contains the handler.
If
scriptInstance is a single script instance, an error alert occurs if the handler is not defined
in the script’s ancestor script. If
scriptInstance is a list of script instances, the message is sent
to each item in the list in turn; if the handler is not defined in the ancestor script, no alert
is generated.
args Optional. Any optional parameters to be passed to the handler.
Example
This example shows how a callAncestor statement can call handlers in the ancestor of a
behavior or parent script.
• This is the parent script:
-- script "man"
property ancestor
on new me, newTool
set ancestor = new(script "Animal", 2)
return me
end
on run me
put "Man running with "&the legCount of me&"legs"
end
• This is the ancestor script:
-- script "animal"
property legCount
on new me, newLegCount
set legCount = newLegCount
return me
end
on run me
put "Animal running with "& legCount &" legs"
end
on walk me
put "Animal walking with "& legCount &" legs"
end
• The following statements use the parent script and ancestor script.
This statement creates an instance of the parent script:
set m = new(script "man")