Programming and Programming Languages Tuesday, Version: December 2nd, 2014 http://papl.cs.brown.edu/2014/index.html http://papl.cs.brown.edu/2014/index.html 1

Programming and Programming Languages Tuesday, Version: December 2nd, 2014 http://papl.cs.brown.edu/2014/index.html http://papl.cs.brown.edu/2014/index.html 17.5 Types Versus Safety If you have ever used the phrases “strong typing” or “weak typing”, define them. That’s what I thought. But thank you for playing. Indeed, the phrases are not only poorly defined, they are also wrong, because the problem is not with the “strength” of the type checker but rather with the nature of the run-time system that backs them.