"Refactoring a statically typed language is easier than refactoring an interpreted one; modifying existing PHP, and even Python, is a difficult chore that engineers shy away from because modifications are likely to create more bugs than they fix."
Over the years I've worked pretty deeply with both static (C++/Java/Scala) and dynamic languages (Python/Ruby). I simply don't agree.
The biggest thing that contributes to refactorability has nothing to do with type safety. Instead unit test coverage, by a mile, is the thing that makes code easy to refactor. In my experience issues of type safety are rare. The same types of bugs are going to crop up in Scala, Python, Java, or even Fortran unless you have tests to help you discover those issues.
I've long felt that type safety is largely a solution to a problem that doesn't really exist. Not in a hugely meaningful way at least. Logic errors are generally independent of type issues, and as such it is code quality and unit test coverage, more than any specific language feature, that lead to highly flexible (and therefore refactorable) code.
Over the years I've worked pretty deeply with both static (C++/Java/Scala) and dynamic languages (Python/Ruby). I simply don't agree.
The biggest thing that contributes to refactorability has nothing to do with type safety. Instead unit test coverage, by a mile, is the thing that makes code easy to refactor. In my experience issues of type safety are rare. The same types of bugs are going to crop up in Scala, Python, Java, or even Fortran unless you have tests to help you discover those issues.
I've long felt that type safety is largely a solution to a problem that doesn't really exist. Not in a hugely meaningful way at least. Logic errors are generally independent of type issues, and as such it is code quality and unit test coverage, more than any specific language feature, that lead to highly flexible (and therefore refactorable) code.