In a new post to his site Anthony Ferrara takes on the topic of typing in PHP, discussing some of the main ideas around the current typing scheme and the discussions being have about potential changes.

There has been a lot of talk about typing in PHP lately. There are a couple of popular proposals for how to clean up PHP's APIs to be simpler. Most of them involve changing PHP's type system at a very fundamental level. So I thought it would be a good idea to talk about that. What goes into a type?

He starts at the highest level, covering what "typing" is in general and some of the tradeoffs that come with being a strongly typed versus weakly typed language. He then gets into PHP's two "semi-independent type systems" - one for objects and one for everything else. He includes some code examples to illustrate and how, for the non-object handling, context means everything for how the types are switched. He also talks about polymorphism, the chaos that could come from scalars becoming objects and a current RFC suggesting the addition of "safe casting" functions to PHP to provide less "magic" when shifting values from one type to another.