Re: [Bug-gnulib] Patch proposal: 1-gary-safe-xfree.patch

[Gary V . Vaughan]

On Monday, September 15, 2003, at 09:21  pm, Paul Eggert wrote:

> > they are none-the-less genuinely useful shorthand that can't be done
> > without macros. Do you have a similar replacement functionality in
> > mind?  Or do you find macros like these to be worse than the extra
> > typing that would be required in their absence?
>
> Yes, because code is clearer when function-like macros act like 
> functions.
>
> Also, less typing is often required if you avoid the macros.  For
> example, compare this code (taken from GNU m4):
>
>   new = XMALLOC (macro_definition, 1);
>
> to this proposed replacement:
>
>   new = xmalloc (sizeof *new);
>
> The latter style is shorter in this case.  (In other cases it's
> longer, of course.)  Another advantage of the latter style is that
> it's immune to changes in the type of the variable.

Okay, sold!  Thanks for the explanation :-)

> Here's a proposed patch to GNU m4 to let it survive the loss of the
> macros in question, so that you can see how much the code is actually
> affected.

It is surprising to see how little effect it has in practice, I have to 
say.  Once the free module is in gnulib, I'll resynch m4 and apply your 
patch.  Thanks again!

> Aside: I notice that m4, after the proposed patch, uses calloc (1, S)
> a lot.  Perhaps we should define a new zalloc (S) that is equivalent
> to calloc (1, S), for convenience?  I've used zalloc in other
> programs.

If zalloc (S) === xcalloc (1, S), that would be cool.  Failing that we 
could always add an XZALLOC macro... :-b

Cheers,
        Gary.
--
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