Re: `match-data' set improperly

[Kim F. Storm]

"Matt Swift" <swift@alum.mit.edu> writes:

> I stand corrected.
> 
> Nevertheless I see a strong case for revising both the documentation and the
> behavior of the function.  

I have fixed the documentation for match-data, so that it explicitly
states that the return value is undefined if the last search failed.

I don't see a strong reason to change the behaviour; it's worked like this
for many years, so people seem to be able to cope with it.  

I think the code is generally easier to understand if there is an
explicit test on the return value of the search command.

On the other hand, I don't object (but I'm not the one to decide!!) to
changing this behaviour in the way you suggest (i.e.  make the various
match-* functions return nil if the last search failed).

Maybe you can write a patch (it can be isolated to search.c I think),
so we can see what's needed?

> The second sentence you quote is almost meaningless.  "did not do
> this" -- did not do WHAT? alter it, or not alter it?  Likewise, one
> cannot tell what might be changed to what in the future.

At least it cleary (:-)) indicates that you should not rely on the
return value, neither now, nor in the future.

-- 
Kim F. Storm  http://www.cua.dk