[racket-dev] Providing macro definitions for BSL programs

See `first-order->higher-order'.

At Sat, 4 Sep 2010 17:00:52 -0400, Nadeem Abdul Hamid wrote:
> Ah, thank you. Now, how about this definition:
> 
> (define-syntax (my-macro stx)
>   (syntax-case stx (->)
>     [(_ (func arg ...) -> rslt)
>      #`(length (cons func (list arg ...)))]))
> (provide my-macro ->)
> 
> i.e. my macro takes the function name, bundles in up in a structure
> (here I just used "cons") and then maybe passes it off to something
> else for processing (here I just used "length" for illustration).
> 
> Now, doing something like this in the BSL file:
>    (my-macro (reward 3) -> "bronze")
> 
> produces:
>   reward: this is a procedure, so it must be applied to arguments
> (which requires using a parenthesis before the name)
> 
> 
> 
> 
> 
> On Sat, Sep 4, 2010 at 4:42 PM, Matthias Felleisen <matthias at ccs.neu.edu> 
> wrote:
> >
> > You need to define and export -> . Otherwise students don't have access to 
> the specific -> in your macro.
> >
> > BTW, injecting macros into *sl languages demands a lot of error checking 
> because novices are easily confused.
> >
> >
> >
> >
> > On Sep 4, 2010, at 4:37 PM, Nadeem Abdul Hamid wrote:
> >
> >> Suppose I make a "teachpack" that defines a macro:
> >>
> >> #lang racket
> >> ...
> >> (define-syntax (my-macro stx)
> >>  (syntax-case stx (->)
> >>    [(_ (func arg ...) -> rslt)
> >>     #`(check-expect (func arg ...) rslt)]))
> >> (my-macro (+ 4 5) -> 10)
> >> (test)
> >> (provide my-macro)
> >>
> >> Running this file works fine.
> >>
> >> Now, how exactly do I make this macro available to programs written in
> >> Beginning/Intermediate Student? Opening up a file in BSL level and
> >> typing:
> >>  (require "my-macro.rkt")
> >>  (my-macro (+ 4 5) -> 9)
> >> gives the error:
> >>  my-macro: bad syntax
> >>
> >> This macro is a simplification of the real thing I'm working on, but
> >> note that the arguments to this macro include name(s) of functions
> >> defined in the BSL file. I though of maybe using
> >> provide-higher-order-primitive, but it doesn't seem to work either.
> >>
> >> --- nadeem
> >> _________________________________________________
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> >
> >
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