Re: Incompatible change without "warning"

[Lute Kamstra <Lute.Kamstra.lists@xs4all.nl>]

Nick Roberts <nickrob@snap.net.nz> writes:

>  >     I'd prefer to define the same `define-obsolete-variable-alias' macro as
>  >     used in XEmacs.
>  > 
>  > That sounds useful.
>
> Does this DTRT?
>
> (defmacro define-obsolete-variable-alias (symbol aliased
> 						 &optional docstring when)
> "Make SYMBOL a variable alias for symbol ALIASED and warn that
> SYMBOL is obsolete. If provided, WHEN should be a string
> indicating when the variable was first made obsolete, for example
> a date or a release number. Fourth arg docstring, if non-nil, is
> documentation for symbol."
>   (list 'progn
> 	`(defvaralias ,symbol ,aliased ,docstring)
> 	`(make-obsolete-variable ,symbol ,aliased ,when)))

The first line of the docstring should be a complete sentence.
Occurrences of argument names in the docstring should be in capitals.
The fourth argument is WHEN, not DOCSTRING.  Personally, I like the
argument names OLDVAR and NEWVAR that XEmacs uses.  What about this:

(defmacro define-obsolete-variable-alias (oldvar newvar
						 &optional when docstring)
  "Make OLDVAR a variable alias for NEWVAR and warn that OLDVAR is obsolete.
If provided, WHEN should be a string indicating when OLDVAR was
first made obsolete, for example a date or a release number.  The
optional argument DOCSTRING specifies the documentation string
for OLDVAR; if it is omitted or nil, OLDVAR uses the documentation
string of NEWVAR"
  `(progn
     (defvaralias ,oldvar ,newvar ,docstring)
     (make-obsolete-variable ,oldvar ,newvar ,when)))

> The version in XEmacs may be better but I've not looked at at it
> deliberately, as I wasn't sure of the implications of copying it.

Lute, who didn't look at XEmacs' implementation either.