Deferring everything to runtime could avoid macros as much as
possible. You can implement input parsing as a function and use the
macro only to glue things together.
#lang racket/base
(require (for-syntax racket/base)
syntax/parse/define
redex/reduction-semantics)
(provide (rename-out
[my-module-begin #%module-begin]))
(define-simple-macro (my-module-begin form ...)
(#%module-begin (handle-expression 'form) ...))
And the function handle-expression can parse the quoted expression
into the syntax of your model, invoke Redex and print the result:
(define (handle-expression expr)
(define t (parse-input expr))
(define results (apply-reduction-relation* R t))
(write (car results)))
(define (parse-input expr)
....)
(where parse-input is a normal function that turns λ into TermLambda
and inserts TermApp when appropriate.)
On Wed, Jan 2, 2019 at 7:47 PM Joey Eremondi <joey.eremo...@gmail.com> wrote:
>
> Thanks for the response!
>
> That's not quite what I want. That will quote lambdas and applications into
> my redex models, but I also want it to reduce them by my reduction relation.
>
> The link I posted discussed how to do that, but only when you write programs
> in the syntax of the model.
>
> Sorry for not being clear about the top-interaction. There's nothing specific
> about top-interaction, I'm having the same problem with module-begin.
> I'm trying to get them both to evaluate the terms using my redex model.
>
> The local-expand function in the article you give looks promising, but I'm
> still figuring out how exactly to use it, particularly with the list of
> expressions for module-begin.
>
>
> On Monday, December 31, 2018 at 8:47:49 PM UTC-8, Sorawee Porncharoenwase
> wrote:
>>
>> I'm a novice too, but here's my attempt to help.
>>
>>>
>>> I'd like to use (define-syntax) to make lambda, #%app, etc. all expand into
>>> terms in my model.
>>
>>
>> This works for me. Is this what you want?
>>
>> #lang racket/base
>>
>> (require redex)
>>
>> (define-language L
>> (term ::=
>> (TermLambda var term)
>> var
>> (TermApp term term)))
>>
>> (define-syntax-rule (lambda (x) b)
>> (term (TermLambda x b)))
>>
>> (default-language L)
>>
>> (lambda (y) y)
>> ;; => '(TermLambda y y)
>>
>> (term (substitute ,(lambda (y) y) y z))
>> ;; => '(TermLambda z z)
>>
>>
>>>
>>> But the problem I'm running into is that #%top-interaction applies (term)
>>> to its argument, which means that 'lambda' and other macros get quoted and
>>> not expanded.
>>
>>
>> I don't totally understand how #%top-interaction is relevant here. It only
>> comes up when you use the REPL, and even then I think it shouldn't do
>> something like that. What are you trying to do in the REPL? And can't you
>> redefine #%top-interaction so that it doesn't do what you don't want it to
>> do?
>>
>>>
>>> Is there a way to make sure that the macros are expanded *before* they are
>>> passed to term, so that (term) receives valid syntax trees for my model,
>>> instead of quoted lambdas and apps?
>>
>>
>> See
>> https://lexi-lambda.github.io/blog/2018/10/06/macroexpand-anywhere-with-local-apply-transformer/.
>> You can also just use the gist here:
>> https://gist.github.com/lexi-lambda/65d69043023b519694f50dfca2dc7d33
>>
>
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