RE: Please add comments to isearch.el

[Drew Adams <drew.adams@oracle.com>]

> > > The point is that Isearch is probably one of the most used emacs
> > > features.  I expect there are lots of packages out there using
> > > its api. I'm not sure overhauling it would be worth the pain it
> > > would cause to everyone who's maintaining/using those packages.
> >
> > +1
> >
> > For example, the recent removal of a layer of indirection for
> > lax-whitespace broke customizations that allowed overriding
> > search-forward-lax-whitespace with own implementation to ignore
> > all possible whitespace instead of just spaces in the search string.
> 
> Hey, I didn't suggest refactoring to begin with.  I suggested to add
> commentary to explain how things work there.  The example you give is
> just another confirmation of my observation that the code in
> isearch.el has long ago crossed the line of being unmaintainable, and
> I think we should fix that ASAP.

FWIW: My +1 above was for caution wrt a major rewrite of the code,
not wrt minor cleanup that improves readability and clearly does
not affect behavior or (preferably) compatibility with the
previous code.

And as I said before that, +1 especially for adding the design
comments that Eli has requested.  And +1 to his suggestion ("to
begin with") that such commenting should come before any code
cleanup.  (Any such comments will also help with any subsequent
proposed code cleanup and discussions about it.)