[racket] Defining a typed language

From: Sam Tobin-Hochstadt (samth at cs.indiana.edu)
Date: Mon Oct 27 22:52:57 EDT 2014

I think what happens here is that the `require` that Konrad added was
getting the correct state initialized, but because of hygiene wasn't
the `require` that was binding the references to `foo`. Then Evan's
changes meant that the state and the binding were coming from the
correct place, and it works.

At least that's what I think is going on -- the interaction of the
language position and syntax-time state still confuses me sometimes.


On Mon, Oct 27, 2014 at 4:43 AM, Konrad Hinsen
<konrad.hinsen at fastmail.net> wrote:
> E. Moran writes:
>  > Thanks for posting this...  I was just wondering if you've considered using the
>  > datum->syntax trick, yet.
> No, because this is the first time I hear about this!
> First of all, your code works fine under Racket 6.1 as well, which is good.
> Second, I don't quite understand how it works in detail, which is bad
> - for me.  It looks like it does the equivalent of adding (require
> a-typed-lang/more) at the beginning of each module that uses
> a-typed-lang. That's what I expected my original code to do as
> well. Your comment points to the difference, which is somehow related
> to the lexical context in which the (require ...) is placed. However,
> understanding why this makes a difference seems to require a clearer
> idea of how "require" works than I currently have. Is this documented
> anywhere?
>  > It'd maybe not be the most elegant solution,
>  > but it could at least serve to get things moving.
> Indeed. I'll update my repository with your working code and a pointer
> to this thread. Thanks a lot!
>  >   (displayln (impersonator? foo))
> A final question: after a quick look at the documentation for impersonators,
> this looks like a check that foo is indeed the original function foo and
> not something wrapped in a contract, right?
> Konrad.
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