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

Indeed, there is lots of recent movement in this direction, using
contracts to bridge the static/dynamic gap (or, if you wish "postpone
the proof obligations to runtime").

Robby

On 5/30/07, Michael Vanier <mvanier at cs.caltech.edu> wrote:
> I find this analogy quite amusing, since every time I use PowerPoint I have to manually turn off all
> the autocorrect options because it invariably corrects things in ways I don't want.  I find myself
> saying "just do what I want!" over and over again.  Apparently other M$ products do the same; I had
> a friend write me an email about improv comedy where all the "improv"s were changed to "improve" --
> after all, everyone knows that "improv" isn't a word, right?
>
> BTW one aspect of this discussion that Matthias alluded to but didn't describe in detail is
> languages with dependent type systems e.g. Epigram.  In those languages, the type system is
> extremely powerful but also undecidable, so the programmer takes on the proof obligations
> him/herself.  My impression is that advanced statically-typed languages are moving in this
> direction, which may make the boundary between such languages and Scheme very small indeed.
>
> Mike
>
> Mark Engelberg wrote:
> > I like Matthias' comparison of static type checking in programming to
> > a spell checker in writing.
> >
> > Spell checkers are useful, but would you use a spell checker if the
> > cost of doing so was that your word processor would not allow you to
> > use any words in your document that were not in the spell checker's
> > dictionary?  It might be worth it to you if you're a really bad
> > speller, if you're working on a pretty standard document with no
> > specialized vocabulary, or if you simply tend to be unimaginative in
> > your word choice.  Of course, the spell checker can't guarantee your
> > document is perfect -- if you make a typo replacing one word with
> > another legal word, the checker probably won't pick up on that.  So
> > really, you need to proofread your document anyway.  Good spellers
> > will make few mistakes, and will catch almost all of the mistakes upon
> > proofreading their own paper.  Those people would gladly ditch a
> > constraining spellchecker, finding it of limited value, and prefer the
> > freedom of expression that comes from choosing their own words.
> >
> > --Mark
> _________________________________________________
>   For list-related administrative tasks:
>   http://list.cs.brown.edu/mailman/listinfo/plt-scheme
>