[plt-scheme] Why do folks implement *dynamically* typed languages?

I'm happy with the answers.

I think that at some point the fellow who created Ruby said to himself
that "I'm going to create a programming language where you can't
detect type errors at compile for these reasons...".

What I want to know is if there are common reasons, or no reasons, or
do people write papers about making this decision?

On 5/30/07, Carl Eastlund <cce at ccs.neu.edu> wrote:
> On 5/30/07, Grant Rettke <grettke at acm.org> wrote:
> > That is what I don't understand. It is so seemingly obvious that it is
> > better to have Sl, yet, the latest hot language that everyone wants to
> > know and love is Ruby, which is a DL. Is it mass hysteria or what is
> > happening?
> >
> > On 5/30/07, Michael Vanier <mvanier at cs.caltech.edu> wrote:
> > > How about modular type systems?  Import this module, get this kind of type checking...
>
> If we could do that -- mix and match type systems freely and easily --
> we would.  They don't combine easily.  It's not like we never thought
> of it.  Those of us who aren't satisfied with just one type system
> often have to settle for Scheme, and the type system(s) in our head.
> Static type checking just can't keep up with us.
>
> We've given you this and other reasons for using dynamic languages,
> and you still say it's "obviously" better to have statically typed
> languages.  Were our answers unbelievable?  Did they fail to make
> sense?  It's fine if you simply disagree - everyone has their own
> favorite kind of language - but if you don't understand what we're
> saying, perhaps you can ask for specific clarification.
>
> --
> Carl Eastlund
>