What is Expressiveness in a Computer Language

[David Hopwood]

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.)

-- 
David Hopwood <david.nospam.hopwood at blueyonder.co.uk>