[racket] syntax-case + boxes and hash literals

Pushed to the git repo.

At Thu, 21 Mar 2013 07:19:15 -0600, Matthew Flatt wrote:
> At Wed, 20 Mar 2013 13:27:02 -0600, Matias Eyzaguirre wrote:
> > As per the pattern grammer in the reference guide, I can use syntax
> > case to match against vectors, lists, and prefab structures [...] But
> > I cannot pattern match inside of the box itself.
> > [...]
> > Why is this? It's my understanding that syntax-case is an older features, 
> and 
> > so perhaps it just wasn't updated when newer constructs arrived.
> 
> Actually, the box notation predates `syntax-case' (certainly in
> Racket/MzScheme, but I think more generally).
> 
> > Was this an intentional decision, or did it slip through?
> 
> The decision was intentional, but arbitrary.
> 
> I don't like the box notation, and I think we probably would have been
> better off without it. But since it's there and supported in most
> syntax contexts, the `syntax-case' implementation should probably
> support it for consistency.
> 
> > If it did, could I ask that it be added to the TODO list?
> 
> Yes, I'll look into it.
> 
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