Re: issue DYNAMIC-EXTENT-FUNCTION, version 1

[sandra%defun@cs.utah.edu (Sandra J Loosemore)]

> Date: Tue, 4 Apr 89 16:23 EDT
> From: David A. Moon <Moon@STONY-BROOK.SCRC.Symbolics.COM>
> 
> Does the compiler committee's model of compilation permit compilation of
> one function to be affected by declarations in the current definition of
> another function that it calls?  I hope so.

Issue COMPILE-ENVIRONMENT-CONSISTENCY talks about situations in which
the compiler is allowed to assume that functions defined in the
compiletime environment retain the same definitions at runtime.  I
don't see anything wrong with applying this technique in those
situations.

> Second, if a function has a SYS:DOWNWARD-FUNCTION declaration in front of
> its body, then the function is implemented with dynamic extent regardless
> of whether the compiler thinks all uses are "downward".  This feature is
> used less often than the first feature, but is still used pretty often.

I vaguely remembered seeing this in some ancient Symbolics
documentation.  It seems a little strange to me to have a declaration
that is only valid in one particular place, but this would indeed take
care of the problem with anonymous lambdas.

> On a sillier note, should we minimize proliferation of names by
> replacing
> 
>    (declare (dynamic-extent-function name))
> 
> with
> 
>    (declare (dynamic-extent #'name)) ?

I wouldn't have any strong objection to doing this, but maybe I'm
being silly too.  :-)

-Sandra
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