What is Expressiveness in a Computer Language

Rob Thorpe robert.thorpe at antenova.com
Fri Jun 23 11:08:50 CEST 2006

David Hopwood wrote:
> Rob Thorpe wrote:
> > David Hopwood wrote:
> >
> >>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.
> >
> > Its easy to create a reasonable framework. My earlier posts show simple
> > ways of looking at it that could be further refined, I'm sure there are
> > others who have already done this.
> >
> > The real objection to this was that latently/dynamically typed
> > languages have a place in it.
> You seem to very keen to attribute motives to people that are not apparent
> from what they have said.

The term "dynamically typed" is well used and understood.  The term
untyped is generally associated with languages that as you put it "have
no memory safety", it is a pejorative term.  "Latently typed" is not
well used unfortunately, but more descriptive.

Most of the arguments above describe a static type system then follow
by saying that this is what "type system" should mean, and finishing by
saying everything else should be considered untyped. This seems to me
to be an effort to associate dynamically typed languages with this
perjorative term.

> > But some of the advocates of statically
> > typed languages wish to lump these languages together with assembly
> > language a "untyped" in an attempt to label them as unsafe.
> A common term for languages which have defined behaviour at run-time is
> "memory safe". For example, "Smalltalk is untyped and memory safe."
> That's not too objectionable, is it?

Memory safety isn't the whole point, it's only half of it.  Typing
itself is the point. Regardless of memory safety if you do a
calculation in a latently typed langauge, you can find the type of the
resulting object.

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