[racket] typed racket and new racket languages?

On Jun 17, 2011, at 4:19 PM, Raoul Duke wrote:

> On Thu, Jun 16, 2011 at 6:17 PM, Richard Lawrence
> <richard.lawrence at berkeley.edu> wrote:
>>> tho i read that even if there are ways to use it, there be dragons in
>>> terms of getting the new language just right wrt type enforcement.
>> 
>> Where did you read this?
> 
> possibly misunderstood the intention behind:
> 
> http://www.ccs.neu.edu/home/matthias/Thoughts/Racket_is____.html
> 
> "To summarize, the creation of a safe language demands a lot of
> attention from the language designer. First, it demands a thorough
> understanding of the invariants that a language should come with.
> Second, it calls for a prediction as to where modules in this language
> will be used so that the language can be equipped with mechanism that
> enforces the invariants in all contexts. Providing support for the
> creation of such enforcement mechanisms is one of the research themes
> of PLT."


Type checking per module is easy. Enforcing the soundness of types across module boundaries is hard. 

In general, making sure that a module body lives up to the constraints of the specified language is easy. Enforcing them across module boundaries is harder. 

That's all -- Matthias