Re: Fixing null-environment and scheme-report-environment

[Richard Kelsey <kelsey@research.nj.nec.com>]

[Following up to my own message]

   Date: Tue, 17 Feb 1998 18:11:56 -0500
   From: Richard Kelsey <kelsey@research.nj.nec.com>

      From: Kent Pitman <kmp@harlequin.com>
      Date: Tue, 17 Feb 98 17:21:35 EST

      Was there a problem with my proposed alternate style?  Is there a reason
      that mentioning the behavior in other implementations we don't control is
      important to do?

   The problem is that your proposal alters the intent, and it's
   too late to do that for R5RS.  Minor changes to the wording to
   make the intent clearer are okay, but that's all.

The discussion has convinced me that I was wrong, and some
change is required.  I guess the intent wasn't as clear as I
thought.  So here is a new version, which is essentially Kent
Pitman's version with Bill Rozas's final paragraph.

                                      -Richard

 (scheme-report-environment _version_)                procedure
 (null-environment _version_)                         procedure

 _Version_ must be the exact integer 5, corresponding to this
 revision of the Scheme report (the Revised^5 Report on Scheme).
 SCHEME-REPORT-ENVIRONMENT returns a specifier for an environment that 
 is empty except for all bindings defined in this report that are either
 required or both optional and supported by the implementation.
 NULL-ENVIRONMENT returns a specifier for an environment that is empty
 except for the (syntactic) bindings for all syntactic keywords 
 defined in this report that are either required or both optional and
 supported by the implementation.

 Other values of _version_ can be used to specify environments
 matching past revisions of this report, but their support is not
 required.  An implementation will signal an error if _version_
 is neither 5, nor another value supported by the implementation.