The Zend Developer Zone has posted the second part of their series (from community member Larry Garfield) about scalar types in PHP 7, one of many features in this "coming soon" release. You can find part one of the series here.
In our last installment, we talked about the benefits of more robust variable typing in PHP 7, and specifically the new support for typed return values. That is already a big boon to the maintainability of our code, but PHP 7 goes a step further. So far, we’ve only talked about typing against classes and interfaces. We’ve been able to type against those (and arrays) for years. PHP 7, however, adds the ability to type against scalar values too, such as int, string, and float.
But wait. In PHP, most primitives are interchangeable. [...] Much the same as return types, scalar types offer greater clarity within the language as well as the ability to catch more bugs earlier. That, in turn, can help encourage more robust code in the first place, which benefits everybody.
He starts by looking at the four new types that have been added in PHP 7:
bool. He includes a code example showing each of them in use on class interfaces and functions. He steps through the code example, explaining how the return type checking is handled for each instance. He also talks about how return type hinting can also benefit static analysis tools, allowing them to potentially find bugs in return values easier than before. Finally he covers strict mode, the method for enforcing types in your code and preventing PHP from doing any "magic" type switching for you. He also includes a code example of this functionality and how, with it enabled, it would have caught an error in his example on a integer vs string input.