Re: Recognizing obsolete external package versions

[Kim F. Storm]

Richard Stallman <address@hidden> writes:

> That code seems basically right
> except that I would rather it avoid calling eval.
> It should give the name of a variable, and the values that are bad.
>
IIRC, we discurage inclusion of version strings in packages.

And even if there is a version string, there is no guarangee that the
version string is stored in a variable.


> I think it would be better to check at the beginning of loading the file
> rather than at the end.  That is possible by searching for "(defvar VARIABLE",
> evaluating the sexp that comes next, and looking at its value.

For the CUA-mode check, there is no such version variable ... instead, it
is simply the presence of the `CUA-mode' feature which triggers the warning.

I could also imagine that for some packages, checking for an old
version need to e.g. check for the (non-)presense of some function or
variable.

>
> That would require detecting the file by its name rather than by
> a feature it provides.

What method would you use to trigger the checking _before_ the load
(even before reading the file)?

AFAICS, we only have eval-after-load to play with here.


-- 
Kim F. Storm <address@hidden> http://www.cua.dk