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

[Guillermo J. Rozas <gjr@martigny.ai.mit.edu>]

|   From: Kent Pitman <kmp@harlequin.com>
|   Date: Tue, 17 Feb 98 15:48:50 EST
|   Subject: Fixing null-environment and scheme-report-environment
|   
|   
|   I think it would be better to say:
|   
|   ==============================================================================
|   
|    (scheme-report-environment _version_)                procedure
|    (null-environment _version_)                         procedure
|   
|    _Version_ must be the exact non-negative integer _k_ (i.e., 5) corresponding
|    to this revision of the Revised^k Report on Scheme.
|   
|    SCHEME-REPORT-ENVIRONMENT returns a specifier for an environment that 
|    contains only the set of bindings defined in this report.
|   
|    NULL-ENVIRONMENT returns a specifier for an environment that contains only
|    the (syntactic) bindings for all the syntactic keywords defined in this
|    report.
|   
|    Whether or not other values of _version_ are supported in any implementation
|    conforming to this report is implementation-defined.  An error is signalled
|    if an argument is given that is neither the revision number of this report 
|    (i.e., 5) nor some other value defined by the implementation.

Had I been smart enough, I would have proposed something closer to
this.

I believe that this is better, although I would change the last
paragraph to be less implementation dependent, and to point at the
intended use of _version_.  More along the lines of

Other values of _version_ are intended to specify environments
matching past reports in the sequence, but their support is not
required by any implementation.  An implementation will signal an
error if the argument is neither k, nor another value supported by the
implementation.

In other words, I'd like the meaning of the argument reserved for its
intended use, but in no way claim that values other than k need be
supported.