Python from Wise Guy's Viewpoint

[Dirk Thierbach]

Andreas Rossberg <rossberg at ps.uni-sb.de> wrote:
> Pascal Costanza wrote:

> Anyway, you are right of course that any type system will take away some 
> expressive power (particularly the power to express bogus programs :-) 
> but also some sane ones, which is a debatable trade-off).

Yep. It turns out that you take away lots of bogus programs, and the
sane programs that are taken away are in most cases at least questionable
(they will be mostly of the sort: There is a type error in some execution
branch, but this branch will never be reached), and can usually be 
expressed as equivalent programs that will pass.

"Taking away possible programs" is not the same as "decreasing expressive
power".

> So there is no inclusion, the "expressiveness" relation is unordered wrt 
> static vs dynamic typing.

That's the important point.

- Dirk