Using 'register' and ^L

Using 'register' and ^L

[Dmitry Antipov]

1) Is there a reason to use explicit 'register' variables nowadays?
    This encumbers sources with no measurable benefits; moreover,
    some GC tracing/debugging techniques assumes that you can take
    an address of any Lisp_Object, which is effectively blocked by
    using 'register'.

2) Why still using ^L?  It looks like a huge empty space in patches
    showing as attachment in some e-mail clients, and I'm curious
    whether someone still uses a printing system relying on ^L page
    breaks :-).

Dmitry

Using 'register' and ^L

[Stephen J. Turnbull]

Dmitry Antipov writes:

 > 2) Why still using ^L?

It's not for printing, it's for section navigation in Emacs and other
capable programmer's editors.  Like GNU man pages (bash.1, I'm looking
at you![1]), they typically far overflow the printed page.

Cf. M-x {forward,backward,mark,narrow-to}-page.

The-S-in-scrollbar-stands-for-suck-ly y'rs,



Footnotes: 
[1]  No, I'm not interested in hearing about The Official GNU
Documentation Format.

Re: Using 'register' and ^L

[Paul Eggert]

Dmitry Antipov wrote:
> 1) Is there a reason to use explicit 'register' variables nowadays?
>     This encumbers sources with no measurable benefits; moreover,
>     some GC tracing/debugging techniques assumes that you can take
>     an address of any Lisp_Object, which is effectively blocked by
>     using 'register'.

There's no reason to use 'register' nowadays in the Emacs source code. 
We haven't bothered to systematically remove 'register' because it's 
been treated like tabs versus spaces, i.e., not worth changing.  But if 
instances of 'register' are causing trouble please just remove them.

Re: Using 'register' and ^L

[Stefan Monnier]

> There's no reason to use 'register' nowadays in the Emacs source code. We
> haven't bothered to systematically remove 'register' because it's been
> treated like tabs versus spaces, i.e., not worth changing.

Exactly.

> But if instances of 'register' are causing trouble please just remove them.
        ^
    specific


Right.  It's also acceptable to remove them on a line you're modifying
for other reasons any way (just like TAB-vs-SPC, again).


        Stefan

Re: Using 'register' and ^L

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

The purpose of ^L is to subdivide code to make it clearer,
both for reading on line and when printed.

I never made every page fit in one printed page.
In some places, that is very hard to do, and I didn't
have enough time to spare for neatness in all the rest of the code.
Nonetheless, the code is easier to understand where we have divided
it nicely.

-- 
Dr Richard Stallman
President, Free Software Foundation
51 Franklin St
Boston MA 02110
USA
www.fsf.org  www.gnu.org
Skype: No way! That's nonfree (freedom-denying) software.
  Use Ekiga or an ordinary phone call.