PHP - Method Chaining - Best Approach?

Question

I need a way to have breadcrumbs that are not generated from the URL.

My thought process is to have a class, "Breadcrumbs" which will work as:

$breadcrumbs = new BreadCrumb('<<')->crumb('www.google.com', 'Google')->crumb('www.youtube.com', 'Youtube');

Which will generate an array, and with each method chain it will push back into the array, resulting in one array which I can then turn into a URL structure.

I have tried the following:

class Breadcrumbs {

    public $del; 
    public $breadcrumbs;

    public function __construct($del)
    {
        $this->breadcrumbs = array();
        $this->del = $del;  

    }

    public function crumb($uri, $name)
    {
         $this->breadcrumbs[] = array($uri => $name);
    }
}

This, however, does not provide an accurate result, and get 'unexpected '->'' when trying to do the structure as I plan to do.

Any ideas to where I am going wrong?

Answer 1

1. To do method chaining, you need to return an object from your method call. Typically you'll want:

   return $this;  // in function crumb()
   

2. The correct syntax to instantiate an object and immediately call a method on it is:

   (new BreadCrumb('<<'))->crumb(..)
   

   Without the extra parentheses it's ambiguous to PHP what you want to do.

3. Aside: you don't need to initialise your array inside the constructor, you can do that while declaring the array:

   public $breadcrumbs = array();
   

4. Aside: this is pretty inefficient:

   .. = array($uri => $name)
   

   You'll have a hard time getting that $uri key back out of the array, which makes your code unnecessarily complicated. You should simply do:

   $this->breadcrumbs[$uri] = $name;
   

   Alternatively, if your URIs aren't guaranteed to be unique, use a structure that's easier to work with later:

   $this->breadcrumbs[] = array($uri, $name);  // $arr[0] is the URI, $arr[1] the name
   

Answer 2

You need to return $this from crumb to be able to do method chaining.

public function crumb($uri, $name)
{
     $this->breadcrumbs[] = array($uri => $name);
     return $this;
}