Variable Variables with Functions - PHP

A great yet widely unused element of variable variables is their ability to be employed with functions. The function name can be set within a variable and then run through calling the variable variable of that variable. Here’s an example:

$function1 = "sort_stuff";
${$function1()}; 
#this sets the result of the sort_stuff() function into a variable
${$function1($var1, $var2, $var3)}; 
#this does the same thing but sends the function parameters

Here’s a quick example of this in action, building on the same program segment I had introduced variable variables with:

$x = "Eric";
$$x = "Seufert";
$function = "value";
echo "${$function()}";
function value() {
return "Eric";
}

This code would output:

Seufert

as the echo statement is printing the value of the variable that gets created from the resultant of the value() function, "Eric". As we have already set $$x (which, following the variable variable, is the same as $Eric) to "Seufert", the same value is outputted, only this time resulting from a function call.

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