Formal comment #112 (defect)

Lexical determination of phases
Reported by:	Andre van Tonder

Component:	libraries
Version:	5.91

Pages : 23 

Summary

The current spec does not specify whether the phases in which bindings
are available are determined lexically.

Description

The following example may or may not be an error according to the
current draft:

    (library foo
      (import r6rs)
      (export f)
      (define (f) 1))

    (library bar
      (import r6rs
              (for foo expand))  ;; This is the wrong level !
      (export g)
      (define-syntax g
       (syntax-rules ()
         ((_) (f)))))    ;; used at level RUN

    (library main
      (import foo bar)   ;; Imports f for level RUN
      (display (g)))     ;; not specified if this is error

I believe the reference implementations all say that this is an error,
so there should not be any technical issue in specifying it to be one.

Suggestion

Allowing the above to not be an error would be in conflict with
lexical scoping of phases. Leaving it unspecified invites portability
problems.

RESPONSE:

Agreed --- we will clarify that levels are determined syntactically.

See also the response to formal comment #92.