Re: Project idea on "Big one hook"

[Jeremy Hankins <nowan nowan org>]

Teika Kazura <teika lavabit com> writes:

> Currently, each module independently puts their functions on hooks.
> So, it is quite obscure both for users and developers what is
> processed, e.g., when a window is mapped.

I seem to recall you mentioning this issue before, and problems that it
caused, but I don't remember the message.  Could you refresh our memory?
Because I'm not certain what problem you're trying to solve.

> So, if "big one hook" like (add-hook 'before-add-window-hook
> system-before-add-window) replaces all system hooked functions in
> before-add-window-hook, and `system-add-window' is coded somewhere
> with comments like "before changing focus, prepare xxx", then birds
> eye view is there. Those who want a hack can tell what should be
> done. When you want to put something on a hook, you can easily choose
> whether it goes at the head or the tail of the hook.

If you need to, you can see what's being done in a hook by evaluating
the hook in sawfish-client or something.  And order isn't supposed to
matter in a hook; if we get in the habit of letting our code depend on a
particular order my worry is that it would become more fragile.  If
there's some reason that order does matter in a particular case it may
be that we need to separate a particular hook into two (or more?) hooks:
one a before-x-hook and one an after-x-hook.

> There's nicety in Sawfish initialization; some open/require can break
> Sawfish, and it's difficult to tell when it happens. This project may
> be challenging, but I think it's possible, at least for some hooks.

Can you give an example of this?  Some of this may indicate bugs that
should be fixed.

> What do you think?

Personally, I like hooks.  Hooks make the code much more extensible by
the end user, and ideally more modular as well.  I can add to a hook in
the module that needs that hook, so if the module isn't loaded that code
never gets run.  Or I could add a hook in my .sawfishrc file if it's
just a quick hack.  On your method it sounds like that wouldn't be
possible.

-- 
Jeremy Hankins <nowan nowan org>