Collaborating syntax-case and er macro

[Takashi Kato]

R7RS syntax-rules is implemented on top of er macro however some cases it doesn't collaborate with syntax-case. Following code should print ok but ng.

(define-library (lib)
  (export foo)
  (import (scheme base))
  (begin
    (define-syntax import (syntax-rules ()))
    (define-syntax foo
      (syntax-rules (import)
    ((_ import) 'ok)
    ((_ _) 'ng))))
  )

(import (rnrs) (lib))

(define-syntax print
  (syntax-rules ()
    ((_ o) (begin (display o) (newline)))))

(print (foo import))

This is because when first rename is done by syntax-case then the given import is renamed to be a global variable, however comparison between literal and the identifier is not correct (ensuring identifier uses current env so it won't be the same in sense of free-identifier=?).

[Takashi Kato]

Actually, this should print ng because import is bound and indicating different binding. The reason why it prints ok is that compare procedure in er-macro-transformer uses macro env instead of usage env so ensured identifier will be macro env identifier (this must be usage env identifier since input is in usage env).

[Takashi Kato]

Using usage env for ensuring identifier on er macro's compare procedure. (Fixes #96)

→ <<cset 72930f87f53e>>

[Takashi Kato]

This case still doesn't work

(import (rnrs) (scheme base))

(define-syntax print
  (lambda (x)
    (syntax-case x ()
      ((_ o) #'(begin (display o) (newline))))))

(let ()
  (define-syntax bar
    (syntax-rules ()
      ((_ m body)
       (let ((m 1))
         (body)))))

  (define-syntax foo
    (syntax-rules ()
      ((_ m body)
       (let ((n 2))
         (let-syntax ((%body
                       (syntax-rules ()
                         ((_) body))))
           (bar m %body))))))

  (let ((n 3))
    (print (foo n (values n)))))

Should print 3 but 1

[Takashi Kato]

Changing er-rename to preserve identifiers the same way as syntax-case. (Fixes #96)

→ <<cset f335dc22f9e3>>