What is Expressiveness in a Computer Language

[David Hopwood]

Rob Thorpe wrote:
> Vesa Karvonen wrote:
> 
>>In comp.lang.functional Anton van Straaten <anton at appsolutions.com> wrote:
>>
>>>Let me add another complex subtlety, then: the above description misses
>>>an important point, which is that *automated* type checking is not the
>>>whole story.  I.e. that compile time/runtime distinction is a kind of
>>>red herring.
>>
>>I agree.  I think that instead of "statically typed" we should say
>>"typed" and instead of "(dynamically|latently) typed" we should say
>>"untyped".
[...]
>>>It's certainly close enough to say that the *language* is untyped.
>>
>>Indeed.  Either a language has a type system and is typed or has no
>>type system and is untyped.  I see very little room for confusion
>>here.  In my experience, the people who confuse these things are
>>people from the dynamic/latent camp who wish to see types everywhere
>>because they confuse typing with safety or having well-defined
>>semantics.
> 
> No.  It's because the things that we call latent types we use for the
> same purpose that programmers of static typed languages use static
> types for.
> 
> Statically typed programmers ensure that the value of some expression
> is of some type by having the compiler check it.  Programmers of
> latently typed languages check, if they think it's important, by asking
> what the type of the result is.
> 
> The objection here is that advocates of statically typed language seem
> to be claiming the "type" as their own word, and asking that others use
> their definitions of typing, which are really specific to their
> subjects of interest.

As far as I can tell, the people who advocate using "typed" and "untyped"
in this way are people who just want to be able to discuss all languages in
a unified terminological framework, and many of them are specifically not
advocates of statically typed languages.

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