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GvR: Strong vs. Weak Typing

Guido van Rossum: Strong versus Weak Typing:

The one thing that troubles me is that all the focus is on the strong typing, as if once your program is type correct, it has no bugs left. Strong typing catches many bugs, but it also makes you focus too much on getting the types right and not enough on getting the rest of the program correct.

Strong typing is one reason that languages like C++ and Java require more finger typing. You have to declare all your variables and you have to do a lot of work just to make the compiler happy.

All that attention to getting the types right doesn't necessarily mean you don't have other bugs in your program. A type is a narrow piece of information about your data. When you look at large programs that deal with a lot of strong typing, you see that many words are spent working around strong typing.

The container problem is one issue. It's difficult in a language without generics to write a container implementation that isn't limited to a particular type. And all the strong typing goes out the door the moment you say, "Well, we're just going to write a container of Objects, and you'll have to cast them back to whatever type they really are once you start using them." That means you have even more finger typing, because of all those casts. And you don't have the helpful support of the type system while you're inside your container implementation.

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12:58 (utc-5)