MACROMEDIA FLASH 8-ACTIONSCRIPT 2.0 LANGUAGE, Справочник

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238 ActionScript language elements
The following code snippet shows how to write the preceding code without using a
with
statement.
someOther_mc._x = 50;
someOther_mc._y = 100;
someOther_mc.gotoAndStop(3);
The
with
statement is useful for accessing multiple items in a scope chain list simultaneously.
In the following example, the built-in
Math
object is placed at the front of the scope chain.
Setting
Math
as a default object resolves the identifiers
cos
,
sin
, and
PI
to
Math.cos
,
Math.sin
, and
Math.PI
, respectively. The identifiers
a
,
x
,
y
, and
r
are not methods or
properties of the
Math
object, but because they exist in the object activation scope of the
function
polar()
, they resolve to the corresponding local variables.
function polar(r:Number):Void {
var a:Number, x:Number, y:Number;
with (Math) {
a = PI * pow(r, 2);
x = r * cos(PI);
y = r * sin(PI / 2);
}
trace("area = " + a);
trace("x = " + x);
trace("y = " + y);
} polar(3);
The following result is displayed in the Output panel.
area = 28.2743338823081
x = -3
y = 3