MACROMEDIA FLASH 8-LEARNING FLASH LITE 1.X ACTIONSCRIPT, Руководство пользователя

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Using the eval() function 17
Using the eval() function
The
eval()
function lets you dynamically reference variables and movie clip instances at
runtime. The
eval()
function takes a string expression as a parameter and returns either the
value of the variable represented by that expression or a reference to a movie clip.
For example, the following code evaluates the value of the
name
ActionScript variable and
assigns the result to
nameValue
:
name = "Jack";
nameValue = eval("name");
// result: nameValue = "Jack"
The
eval()
function is often used with
for()
loops and the
add
(string concatenation)
operator to create string-based arrays, because Flash Lite doesn’t support native array data
structures. For more information, see
“Emulating arrays” on page 11 .
You can also use
eval()
to reference movie clip instances by name. For example, suppose you
had three movie clips named
clip1
,
clip2
, and
clip3
. The following
for()
loop increments
the x position of each clip by 10 pixels:
for(index = 1; index <= 3; index++) {
eval("clip" add index)._x += 10
}