What is a type error?

[Marshall]

Chris Smith wrote:
> Darren New <dnew at san.rr.com> wrote:
> > Chris Smith wrote:
> > > Unless I'm missing your point, I disagree with your disagreement.
> > > Mutability only makes sense because of object identity (in the generic
> > > sense; no OO going on here).
> >
> > Depends what you mean by "object".
> >
> > int x = 6; int y = 5; x = y;
> >
> > I'd say x was mutable, with no "identity" problems involved?
>
> The variable x definitely has identity that's independent of its value.

I'm not sure what you mean by that.

>  I also see, though, that the majority (so far, I'd
> say all) of the potential uses for which it's worth introducing mutation
> into an otherwise mutation-free language allow the possibility of
> aliasing, which sorta makes me wonder whether this problem is worth
> solving.

What about my example of SQL? Mutation, no pointers, no aliasing.
Yet: useful.


Marshall