Lingo Dictionary > A-C > callAncestor

 

callAncestor

Syntax

callAncestor handlerName, script, {args...}

Description

Command; sends a message to a child object's ancestor script, where handlerName is the name of the handler to be activated, script references the script instance or a list of script instances, and args are any optional parameters to be passed to the handler.

If script is a single script instance, an error alert occurs if the handler is not defined in the ancestor of the script.

If script is a list of script instances, the message is sent to each item in the list in turn. In this case, if the handler is not defined in an ancestor script, no alert is generated.

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.

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")

This statement makes the man walk:

call #walk, m
-- "Animal walking with 2 legs"

This statement makes the man run:

set msg = #run
callAncestor msg, m
-- "Animal running with 2 legs"

This statement creates a second instance of the parent script:

set m2 = new(script "man")

This statement sends a message to the ancestor script for both men:

callAncestor #run,[m,m2]
-- "Animal running with 2 legs"
-- "Animal running with 2 legs"

See also

ancestor, new()