/ScriptX/Documentation/HTML Files/language guide HTML/chars/cdreturn.gif)
25
global z, x := 15
(
local q:= 10
z := x + q
)
z -- evaluate z
q-- evaluate q
-- ** Warning: Undeclared global q
Note that z continued to exist outside the block because it was declared globally. The variable q, however, was declared locally, and so is only available within the block expression in which it was defined. In the example that follows, note that the local definition within the block overrides the global definition outside the block.
global var1 := "string"
(
local var1 := "a different string"
var1 -- the block returns the value of this because it's
-- the last expression in the block
)
var1
The first
var1 evaluates to the value of the local assignment, as declared in the block. The second var1 , which occurs after the end of the block, returns the value of the global var1 variable. When ScriptX encounters a variable reference, it first checks the local scope for the value of that variable, and then each surrounding variable scope. This causes local variables to "hide" the values of global variables and local variables of the same name, including variables that may contain substrate classes, objects, and functions.
The following example shows that the global variable is visible inside the block until it is overriden by a local variable with the same name. After the block's scope has ended, the local variable no longer exists.
global a, b:2, c:3
(
a := b
local b:5
c := b
)
a -- evaluate a
b -- evaluate b
c -- evaluate c
This document is part of the ScriptX Language Guide, one of the volumes of the ScriptX Technical Reference Series. ScriptX is developed by the ScriptX Engineering Team at Apple Computer, successor to the Kaleida Engineering Team at Kaleida Labs, Inc.