What is Expressiveness in a Computer Language

[Rob Thorpe]

Torben Ægidius Mogensen wrote:
> "Rob Thorpe" <robert.thorpe at antenova.com> writes:
>
> > Torben Ægidius Mogensen wrote:
>
> > > That's the point: Bugs that in dynamically typed languages would
> > > require testing to find are found by the compiler in a statically
> > > typed language.  So whil eit may take onger to get a program thatgets
> > > past the compiler, it takes less time to get a program that works.
> >
> > In my experience the opposite is true for many programs.
> > Having to actually know the precise type of every variable while
> > writing the program is not necessary, it's a detail often not relevant
> > to the core problem. The language should be able to take care of
> > itself.
> >
> > In complex routines it can be useful for the programmer to give types
> > and for the compiler to issue errors when they are contradicted.  But
> > for most routines it's just an unnecessary chore that the compiler
> > forces on the programmer.
>
> Indeed.  So use a language with type inference.

Well, for most purposes that's the same as dynamic typing since the
compiler doesn't require you to label the type of your variables.  I
occasionally use CMUCL and SBCL which do type inference, which is
useful at improving generated code quality.  It also can warn the
programmer if they if they reuse a variable in a context implying that
it's a different type which is useful.

I see type inference as an optimization of dynamic typing rather than a
generalization of static typing.  But I suppose you can see it that way
around.