What is Expressiveness in a Computer Language

[Rob Thorpe]

David Hopwood wrote:
> Rob Thorpe wrote:
> > Matthias Blume wrote:
> >>"Rob Thorpe" <robert.thorpe at antenova.com> writes:
> >>
> >>>I think we're discussing this at cross-purposes.  In a language like C
> >>>or another statically typed language there is no information passed
> >>>with values indicating their type.
> >>
> >>You seem to be confusing "does not have a type" with "no type
> >>information is passed at runtime".
> >>
> >>>Have a look in a C compiler if you don't believe me.
> >>
> >>Believe me, I have.
> >
> > In a C compiler the compiler has no idea what the values are in the program.
> > It knows only their type in that it knows the type of the variable they
> > are contained within.
> > Would you agree with that?
>
> No. In any language, it may be possible to statically infer that the
> value of an expression will belong to a set of values smaller than that
> allowed by the expression's type in that language's type system. For
> example, all constants have a known value, but most constants have a
> type which allows more than one value.
>
> (This is an essential point, not just nitpicking.)

Yes, I agree.  That does not apply in general though.
In general the value of the variable could be, for example, read from a
file, in which case the compiler may know it's type, but not any more.

I was talking about the general case.