Microsoft Word - Core PHP Programming Using PHP to Build Dynamic Web Sites

(singke) #1

Dynamic Function Calls


You might find yourself in the position of not knowing which function should be called
when you are writing a script. You want to decide based on data you have during
execution. One way to accomplish this is to set a variable with the name of a function and
then use the variable as if it were a function.


If you follow a variable with parentheses, the value of the variable will betreated as the
name of a function. Listing 4.8 demonstrates this. Keep in mind that you can't refer to
built-in functions in this way. Setting myFunction to be print will cause an error.


Listing 4.8 Dynamically Calling a Function


<?
function write($text)
{
print($text);
}


function writeBold($text)
{
print("$text");
}


$myFunction = "write";
$myFunction("Hello!");
print("
\n");


$myFunction = "writeBold";
$myFunction("Goodbye!");
print("
\n");
?>

Free download pdf