Variable function parsing into string

It works not properly

[ilin]

//Variable function
$func = 'foo';
//Functions and method calls inside {$} work since PHP 5
echo "text1 {$func(44)} text2";
function foo($id) 
{
echo "foo($id)";
}

output:
foo(44)text1 text2

The result of function parsed.
But result was parsed BEFORE any text.
How can I parse function BETWEEN text blocks?

[cameraman]

Welcome to Webmaster World, ilin.

Inneresting, didn't know you could do that.
Change foo to:
function foo($id)
{
return "foo($id)";
}

[ilin]

cameraman, thank You very much!
It works right.