I just tried replacing the lexical context of path, and got this:
#lang racket/load
;;provider
(module T racket
(provide a)
(define a 1))
;; requirer
(module R racket
(require (for-syntax syntax/parse syntax/strip-context))
(define-syntax (test-binding stx)
(syntax-parse stx
[(_ path)
#:with new-path (replace-context #'here #'path)
#'(let () (local-require (only-in new-path a)) a)]))
(test-binding 'T))
;; go
(require 'R)
So I think when it expands (only-in path [a a]), it introduces a with the
lexical context of the second a,
bit when it expands (only-in path a), it introduces a with the lexical context
of path.
On Nov 6, 2014, at 4:36 PM, Spencer Florence <spen...@florence.io> wrote:
> Thanks! That fixed it!
>
> Although I'm still curious as to why the error happens in the first place.
> On Thu Nov 06 2014 at 3:32:02 PM Alexander D. Knauth <alexan...@knauth.org>
> wrote:
> I think I had a similar sort of problem about a year ago (I was at either
> RacketCon or a Hackathon that same weekend and Mathew Flatt figured it out),
> and the solution was changing (only-in path a) to (only-in path [a a]).
>
> #lang racket/load
> ;;provider
> (module T racket
> (provide a)
> (define a 1))
> ;; requirer
> (module R racket
> (require (for-syntax syntax/parse))
> (define-syntax (test-binding stx)
> (syntax-parse stx
> [(_ path)
> #'(let () (local-require (only-in path [a a])) a)]))
> (test-binding 'T))
> ;; go
> (require ‘R)
>
>
> On Nov 6, 2014, at 4:09 PM, Spencer Florence <spen...@florence.io> wrote:
>
> > Hi All,
> >
> > I've been struggling to have a macro be given a path then require something
> > from that path. The following code produces and "Unbound Identifier" error,
> > although I would expect it to evaluate to 1. Could someone provide insight
> > into what is going on?
> >
> > #lang racket/load
> > ;;provider
> > (module T racket
> > (provide a)
> > (define a 1))
> > ;; requirer
> > (module R racket
> > (require (for-syntax syntax/parse))
> > (define-syntax (test-binding stx)
> > (syntax-parse stx
> > [(_ path)
> > #'(let () (local-require (only-in path a)) a)]))
> > (test-binding 'T))
> > ;; go
> > (require 'R)
> >
> >
> > P.S. I attempted to do this with `dynamic-require,` but that failed because
> > in my actual program `path` is sometimes `(submod "..")`, which caused an
> > error about not having a base path.
> >
> > ____________________
> > Racket Users list:
> > http://lists.racket-lang.org/users
>
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