[Gcl-devel] Re: tertium non datur: ANSI help

[Camm Maguire]

Greetings!

Robert Boyer <address@hidden> writes:

> Can you explain to me what the ANSI standard is talking
> about here?
> 
>    A call is a safe call if each of the following is either safe code
>    or system code (other than system code that results from macro expansion of
>    programmer code):
> 
>    * the call.
>    * the definition of the function being called.
>    * the point of functional evaluation
> 

Just an idea -- perhaps the last here means safely extracting the
function from the function designator, e.g. 'foo, #'foo. '(setf foo),
....

Take care,

> What are the three distinctions they are trying to make?
> What is the difference between "the call" and "the point of
> functional evaluation"?
> 
> I can get to two distinct matters.
> 
> If we have somewhere, say,
> 
>   (locally (declaim (optimize (safety <m>)))
>     (defun foo () (bar))
> 
> and somewhere else, say,
> 
>   (locally (declaim (optimize (safety <n>)))
>     (defun bar () (fap))
> 
> then the safety setting when the "defun foo" is processed,
> e.g., compiled, is clearly important, and the safety setting
> when the "defun bar" is processed, e.g., compiled, is also
> clearly important.  But what is the "third" thing that has
> to be safe?
> 
> Just to be definite.  I am focusing here on this one call:
> (bar).  So bar is definitely "the function being called",
> obviously.  It is clear what "the definition" of bar is.
> Isn't the point of functional evaluation just exactly where
> the call (bar) "is"?  In the body of foo?  Or is it
> somewhere else?
> 
> What other safety setting anywhere could affect anything?
> 
> Are they suggesting that <p> can be relevant to whether the
> call (bar) is safe?
> 
>   (locally (declaim (optimize (safety <p>)))
>            (foo))
> 
> Thanks,
> 
> Bob
> 
> 
> 

-- 
Camm Maguire                                            address@hidden
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