Re: remote environments

[David N Gray <Gray@DSG.csc.ti.com>]

> I think it would be much nicer if we could make compile-time classes
> instantiable.  However, I agree that it would not ruin the language to
> omit that feature if we can't figure out how to do it.

I agree that it would be nice, and intend to support it in our
implementation (it's already implemented but has a few problems to be
worked out).  It's just a question of whether it can be specified in a
way that everyone can live with.

> 	 - If so, do initforms have access to macros and constants defined
> 	   earlier in the file?
> 
> Initforms certainly have access to those things since they are included
> in the initforms' environment.  I think 88-002R implies this.

I intend to implement it that way since it is a reasonable thing to
expect.  However, I'm not aware of any language in 88-002R that requires
this ("implies" isn't good enough).  In fact, proposal
COMPILE-FILE-HANDLING-OF-TOP-LEVEL-FORMS explicitly says that macro
definitions are _not_ necessarily available to the evaluator during
compile-time evaluations.

>     I think that the standard could take a simple, minimal, approach that
>     would still satisfy the most common usages.  Suppose we said:
> 
>     DEFCLASS
...
>		 One way to look at this would be to
>       say that it is implementation-dependent whether FINALIZE-INHERITANCE
>       works or signals an error when given a class defined in the
>       compile-time environment.
> 
>     [And no compile-time generic-function or method objects at all]
> 
> This is an interesting idea, but I think it's too restrictive.  Here's a
> plausible and many-times proposed application for metaobjects which
> would not be possible if we adopted this idea.  Suppose you made an
> optimizing compiler that is allowed to assume that no class
> redefinitions, no method redefinitions, and no newly-defined subclasses
> will be created at run time.  The compiler is to take advantage of this
...

I certainly don't want to prevent any implementation from doing that.
The real issue is what is the minimal functionality that all
implementations must support.