There are two ways to make a variable visible to a command or function. First,
you can declare the variable as a global or script local. A global variable is
one that is available to any handler that declares it, or optionally, to any
script that declares it outside any handlers:
on doSomething
global myValue
end doSomething
on doSomethingElse
global myValue
end doSomethingElse
The second way is to pass the value to the command or function:
on doAnotherthing myValue
-- some commands
end doAnotherthing
The globals or script locals are persistent while Revolution is running. The
parameter is NOT persistent, in that as soon as doAnotherThing terminates,
myValue is destroyed.
You could make it a function:
function doYetAnotherThing myValue
-- do things that change myValue
return myValue
end doYetAnotherThing
and then preserve myValue by putting the result of the function back into
myValue:
put doYetAnotherThing(myValue) into myValue
Seems silly, but there you have it. The better way to do this without using a
function is by declaring the parameter using the @ keyword (keychar??):
on doOneLastThing @myValue
-- some commands that change myValue
end doOneLastThing
in which case myValue will not be destroyed when doOneLastThing terminates,
because the command was passed to the function as a variable and not the value.
The calling program will see the change in myValue.
That about sums it up. Globals and Script Locals are for persistence while
Revolution is running. They are visible to whatever declares then, including
ALL handlers in a script that declares it outside of any handler like so:
local myValue -- or global if you want it to be visible by ALL handlers
-- in ALL scripts in your stack or application
on okayThisLastThing
-- do something to the most used variable ever
end okayThisLastThing
Parameters are for passing values that get destroyed when the command or
function terminates.
Bob
On Feb 8, 2010, at 9:14 AM, Andrew Kluthe wrote:
> Any suggestions on helping this RevNub get this sorted out? In your
> response, try to include how the params are used in handlers. Thank you so
> much in advance for your replies!
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