Re: [Emacs-diffs] trunk r117987: * internals.texi (Stack-allocated Objects): Describe this feature.

[Paul Eggert]

On 09/30/2014 10:55 AM, Stefan Monnier wrote:
> I don't know C99 and I hence don't know
> what is the "corresponding scope" of those new thingies.

I gave a shot at improving that part of the documentation in trunk bzr 
117990.

> See my other message about these macros.

Sorry, I don't remember which message that was?

> I'd much prefer
> declaration-level macros, which would come with clear scoping.

Although I can see the attraction of their clearer scoping, requiring a 
name for every temporary can make code considerably harder to read.  For 
example, we'd have to replace this:

  caller = concat3 (SCOPED_STRING (" <"), caller, SCOPED_STRING (">"));

with something like this:

  SCOPED_STRING (space_lessthan, " <");
  SCOPED_STRING (greaterthan, ">");
  caller = concat3 (space_lessthan, caller, greaterthan);

Regardless of whether we use declaration-style macros, there is one 
thing I'd like to change: the macro names.  These macros are not about 
*scope*; they are about *lifetime*.  How about the prefix "auto_" (from 
the C keyword 'auto') rather than "scope_"?  Or maybe "block_" because 
it's block lifetime?  ("auto_" is shorter....)

Also, I capitalized SCOPED_STRING on the theory that it is often not 
implemented as a function.  On second thought since it can be (and 
sometimes is) implemented as a function I'm thinking we should make it 
lower-case, as scoped_cons etc. are.  (Correcting its prefix of course.)