Re: [plt-scheme] Annotative forms in expand-program?

[Robert Bruce Findler <robby@ccs.neu.edu>]

It probably won't matter for Matt's problem, but for those who are
following this thread, there is one tidbit I forgot to mention in my
last post. 

The syntax system will actually direct you to the source of the
`check-top-level-no-defined' and `check-boolean', so if you are writing
a compiler, you can query the syntax objects for the definition of
those functions.

Robby

At Sun, 9 Jun 2002 13:48:03 -0500 (EST), Matt Jadud wrote:
> 
> 	I was thinking I was all set in using the expanded form of a program,
> and I'd gain magical compatibility with any program implemented in DrScheme.
> 
> The program
> 
> (define (fact n)
>   (if (zero? n)
>       1
>       (* n (fact (n (- n 1))))))
> 
> Expands as follows under the language setting "Textual MzScheme":
> 
> (define-values
>   (fact)
>   (lambda (n)
>     (if (#%app (#%top zero?) n)
> 	(#%datum 1)
>         (#%app (#%top *) n (#%app (#%top fact)
> 				  (#%app (#%top -) n (#%datum 1)))))))
> 
> Under the "Beginning Student" language, however, I get the following:
> 
> (begin
>  (#%app check-top-level-not-defined (quote define) (quote-syntax fact))
>  (define-values (fact)
>    (lambda (n)
>      (if (#%app verify-boolean (#%app zero? n) (quote if))
> 	 (#%datum 1)
>        (#%app * n (#%app (#%top fact)
> 			 (#%app - n (#%datum 1))))))))
> 
> I had to fgrep through the collections directory to find, in the "private"
> subdirectory of the "lang" collection the string "check-top-level." These
> run-time extentions for use in Beginner Scheme show up in the expansion of the
> definitions window; if any language can introduce arbitrary code to be
> evaluated at run-time into the primitive language, how do I handle expressions
> defined in modules that have no meaning in the language of my compiler?
> 
> 	I thought I had a handle on this, but perhaps I didn't; am I missing
> something very obvious?
> 
> 	Thanks,
> 	Matt
> 
> ________________________________________________________________________
> Matt Jadud                            http://www.cs.indiana.edu/~mjadud/
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