MACROMEDIA FLASH MX, Справочник

Страница: 41 / 1104

() (parentheses) 41
() (parentheses)
Availability
Flash Player 4.
Usage
(expression1 [, expression2])
( expression1, expression2 )
function ( parameter1,..., parameterN )
Parameters
expression1, expression2
Numbers, strings, variables, or text.
function
The function to be performed on the contents of the parentheses.
parameter1...parameterN
A series of parameters to execute before the results are passed as
parameters to the function outside the parentheses.
Returns
Nothing.
Description
Operator; performs a grouping operation on one or more parameters, performs sequential
evaluation of expressions, or surrounds one or more parameters and passes them as parameters to
a function outside the parentheses.
Usage 1: Controls the order in which the operators execute in the expression. Parentheses override
the normal precedence order and cause the expressions within the parentheses to be evaluated
first. When parentheses are nested, the contents of the innermost parentheses are evaluated before
the contents of the outer ones.
Usage 2: Evaluates a series of expressions, separated by commas, in sequence, and returns the
result of the final expression.
Usage 3: Surrounds one or more parameters and passes them as parameters to the function
outside the parentheses.
For more information, see “Operator precedence and associativity” in Using ActionScript in Flash .
Example
Usage 1: The following statements show the use of parentheses to control the order in which
expressions are executed (the value of each expression appears in the Output panel):
trace((2+3)*(4+5));//displays 45
trace(2+(3*(4+5)));//// displays 29
trace(2+(3*4)+5);// displays 19
Usage 2: The following example evaluates the function
foo()
, and then the function
bar()
, and
returns the result of the expression
a + b
:
var a:Number = 1;
var b:Number = 2;