How does the pin behavior work?

I want to know the math behind the pin behavior.

Reason being is that I want to pin an object but also be able to put behaviors on the object like bullet to create advanced movement.

So, how can I calculate the position of a sprite by "pinning" it to something, but without using the behavior itself?

You can see the source code in \Program Files\Construct 2\exporters\html5\behaviors\pin\runtime.js

Also, check out Pin+ behavior, it may have the features you need:

construct.net/en/forum/extending-construct-2/addons-29/behavior-pin-123766