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

From: Michael Vanier (mvanier at cs.caltech.edu)
Date: Wed May 30 01:47:41 EDT 2007

That sounds great, in principle.  How do you check your types statically?


Carl Eastlund wrote:
> Which way are you asking?  Your subject line asks one question, but
> your content asks another.  I guess you are trying to ask "why dynamic
> languages?"
> Here's why I like dynamically typed languages: because types are far
> too important too me.  I'm not going to let some tyrannical type
> checker decide in advance what type system I'm going to use for all
> programs.  I'm going to use whatever notion of types is appropriate
> for my current task, and check as much of that statically as I can.
> If ML's type checker, or Haskell's type checker, or Java's type
> checker can't verify my invariants, or worse reject my program as an
> error - all static type checkers are guaranteed to reject some 100%
> correct programs as errors - I'd be out of luck in those languages.
> I'm always in luck with Scheme.
> It puts a lot of responsibility on me to get the system right, but I
> can live with that.
> On 5/29/07, Grant Rettke <grettke at acm.org> wrote:
>> Hi folks,
>> Why do people design dynamically typed (DL) languages over statically
>> typed languages (Sl)?
>> In the case of Lisp, it seems obvious, metaprogramming. That said, you
>> can metaprogram in SLs, so maybe it is not so obvious.
>> Are there any good papers or books on this matter?

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