preg_replace_callback() - Callback inside current object instance

Question

Warning: preg_replace_callback() [function.preg-replace-callback]: Requires argument 2, \'info\', to be a valid callback in [...]

public function getDisplay(         


        

Answer 1

Instead of using anonymous functions or more complex methods, you can just use one of methods supported for passing callbacks (see the documentation on callbacks):

A method of an instantiated object is passed as an array containing an object at index 0 and the method name at index 1.

To pass "info" method of current object as a callback, just do the following:

array($this, 'info')

and pass it wherever you want to use "info" method as a callback within one of the objects other methods.

Answer 2

The correct way to do this would be with a closure:

public function getDisplay() {

    // While $this support in closures has been recently added (>=5.4.0), it's
    // not yet widely available, so we'll get another reference to the current
    // instance into $that first:
    $that = $this;

    // Now we'll write that preg... line of which you speak, with a closure:
    return  preg_replace_callback('!\{\{(\w+)\}\}!', function($matches) use($that) {
        return $that->info[$matches[1]];
    }, $this->display);

}

Answer 3

This solved it:

public function getDisplay(){
    return  preg_replace_callback('!\{\{(\w+)\}\}!', array(get_class($this), '_preg_replace_callback'), $this->display);
}

private function _preg_replace_callback($matches){
    return $this->info[$matches[1]];
}

I did try this approach before, but didn't use the get_class() function to wrap $this. Oh bother...