[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: dynamic vs. static typing
On Nov 18, 2003, at 1:46 PM, Ken Shan wrote:
> It seems that under #2 you meant to say that "variables or arguments
> are not assigned to types which contain methods which they [i.e., the
> variables or arguments] do not respond to" -- is that right?
> Assuming that, what you said seems reasonable to me. Two caveats,
> though. First, I don't see any reason to distinguish between
> arguments, and return values. I particularly don't see why your two
> items above restrict themselves to "variables" and "variables or
> arguments", respectively.
Call them all variables then.
Ok, now let's take a simple and common example such as a List that can
hold any collection of objects (of different types). How do we
implement such a thing in a statically typed system? For example, let's
say our List object has an "at(index)" method which returns the object
at the specified index. What would the return type for such a method
be? - without being the equivalent of a void *, in which case, we can
once again get "object does not respond to this message" errors, which
is what the static type system was supposed to prevent.