[racket] Macros, Eval and dynamic syntax?

Nevermind.  I was making things way too complicated.  Obviously I can just
return #'(pattern) in the event I'd like the caller's procedure invoked.

Thanks.


On Wed, Apr 17, 2013 at 11:29 AM, Scott Klarenbach <scott at pointyhat.ca>wrote:

> Hi there,
>
> With my limited macro knowledge I'm trying to accomplish the following:
>
> Create a macro that accepts custom dsl-ish syntax.  In addition to the
> custom syntax, a user can also provide a procedure.
>
> For example:
>
> (my-macro [(name:first-name type:string required:#t)
>                   (name:last-name type:string)
>                   (hash 'id middle-name 'type 'string)
>                   (lambda () (do-something-arbitrary))])
>
> The first two are the dsl, the next two are procedures.  The macro
> converts the shorthand key:val syntax into hashes internally and does some
> other processing.  So far, so good.
>
> But additionally I'd like to invoke any provided procedure (any datum that
> doesn't match the dsl syntax) in lieu of the short-hand syntax.
>
> What's the "correct" way to invoke the procedures, since I'm sure I'm
> doing it wrong.
>
> So far, I'm converting each syntax expression that's not in the dsl using
> syntax-datum.  But then they're quoted, and I have to use eval, which
> imposes a bunch of namespace complexity.  Is there a way to invoke syntax
> without eval?  Or is there a much better way entirely to write the macro so
> that the above would work?
>
> Thanks.
>
>
> --
> Talk to you soon,
>
> Scott Klarenbach
>
> PointyHat Software Corp.
> www.pointyhat.ca
> p 604-568-4280
> e scott at pointyhat.ca
> 200-1575 W. Georgia
> Vancouver, BC V6G2V3
>
> _______________________________________
> To iterate is human; to recur, divine
>



-- 
Talk to you soon,

Scott Klarenbach

PointyHat Software Corp.
www.pointyhat.ca
p 604-568-4280
e scott at pointyhat.ca
200-1575 W. Georgia
Vancouver, BC V6G2V3

_______________________________________
To iterate is human; to recur, divine
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