What is Expressiveness in a Computer Language

[Torben Ægidius Mogensen]

Pascal Costanza <pc at p-cos.net> writes:

> Torben Ægidius Mogensen wrote:
> 
> > On a similar note, is a statically typed langauge more or less
> > expressive than a dynamically typed language?  Some would say less, as
> > you can write programs in a dynamically typed language that you can't
> > compile in a statically typed language (without a lot of encoding),
> > whereas the converse isn't true.
> 
> It's important to get the levels right here: A programming language
> with a rich static type system is more expressive at the type level,
> but less expressive at the base level (for some useful notion of
> expressiveness ;).
> 
> > However, I think this is misleading,
> > as it ignores the feedback issue: It takes longer for the average
> > programmer to get the program working in the dynamically typed
> > language.
> 
> This doesn't seem to capture what I hear from Haskell programmers who
> say that it typically takes quite a while to convince the Haskell
> compiler to accept their programs. (They perceive this to be
> worthwhile because of some benefits wrt correctness they claim to get
> in return.)

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.

        Torben