Calling Another Module From A Controller

With the Trongate framework, there are two mechanisms by which a module can load another module.

The first method is calling a module from within a controller file.  The second is calling a module from a view file.  Here's how to call a module from a controller file.

$this->module('module_name');
$this->module_name->do_something();

As you can see, just two lines of code is all it takes to invoke a method from a different module.

Below is a hypothetical example of a method that calls upon a 'tax' module to calculate a price after tax has been added.

function _calculate_total($price) {

    //load the 'tax' module
    $this->module('tax');

    //add tax, using the 'Tax' module
    $total = $this->tax->_add_tax($price);
    return $total;
}

Below is an example of a method that calls upon three other modules to calculate a total price.  The modules being called here will be named 'tax', 'shipping' and 'discount'.  So, we're imagining:

• a module called 'tax' for calculating how much tax needs to be paid
• a 'shipping' module for calculating the cost of shipping
• a 'discount' module that's dedicated to applying any relevant discounts that are available

Here's the code:

​function _calculate_total($price) {
    $this->module('discount');
    $this->module('shipping');
    $this->module('tax');

    $price = $this->tax->_add_tax($price);
    $price = $this->shipping->_add_shipping($price);
    $total = $this->discount->_apply_discount($price);
    return $total;
}