I think a lot of private members should be declared protected

[etranger]

Lack of or incomplete support of certain features (nullable typed class constants in my case) makes it tempting to extend the base Printer class and introduce my own implementation, but it's very hard due to massive internal dependencies on private methods.

Declaring PsrPrinter class as final also makes it a deadend in terms of extensibility.

Simply changing private methods to protected, and removing final from PstPrinter would greatly improve extensibility of the library without compromising... well, anything.

As a sidenote, support for nullable typed class constants would be a welcome addition.

[dg]

fixed, constant type can be nullable 03acaa6 and PsrPrinter is not final c511194

I need to consider protected methods carefully; they can complicate further development.