Emacs C source, suggested reading order

Emacs C source, suggested reading order

[joao]

Hi all,

I wanted to write some emacs lisp code to display the contents of registers,
where I've saved several window configurations. I was thinking of a list of
registers identified by a, b, c, ..., with, for each one, the names of the
buffers/files displayed in each window.

Unfortunately the Elisp Manual states clearly that

       Primitives to look inside of window configurations would
    make sense, but none are implemented.  It is not clear they
    are useful enough to be worth implementing.

So I guess it's time to start reading that Emacs C source code, so I can add
the primitive I need. I've found the window config functions in window.c, but
obviously there's a lot to understand in this (big) source.

Does anyone have a suggested reading order in all these C source files ? are
there some useful comments buried inside any particular file ? things like
description/explanation of how lisp objects/functions are implemented in C ? or
the interface between lisp and C ?

Suggestions welcome. Otherwise I'll start with emacs.c :-) 

Thx,
Joao


-- 
João Moreira de Sá Coutinho      
(joao at teaser dot fr)

Re: Emacs C source, suggested reading order

[Rob Thorpe]

joao <joao@nospam.net> wrote in message news:<m3u12mqlnh.fsf@localhost.localdomain>...
> Hi all,
> 
> I wanted to write some emacs lisp code to display the contents of registers,
> where I've saved several window configurations. I was thinking of a list of
> registers identified by a, b, c, ..., with, for each one, the names of the
> buffers/files displayed in each window.
> 
> Unfortunately the Elisp Manual states clearly that
> 
>        Primitives to look inside of window configurations would
>     make sense, but none are implemented.  It is not clear they
>     are useful enough to be worth implementing.
> 
> So I guess it's time to start reading that Emacs C source code, so I can add
> the primitive I need. I've found the window config functions in window.c, but
> obviously there's a lot to understand in this (big) source.
> 
> Does anyone have a suggested reading order in all these C source files ? are
> there some useful comments buried inside any particular file ? things like
> description/explanation of how lisp objects/functions are implemented in C ? or
> the interface between lisp and C ?
> 
> Suggestions welcome. Otherwise I'll start with emacs.c :-) 

Start with lisp.h, then read emacs.c or eval.c

I can't advise you further than that since I haven't got further myself!

Re: Emacs C source, suggested reading order

[Eli Zaretskii]

> From: joao <joao@nospam.net>
> Newsgroups: gnu.emacs.help
> Date: 24 Jan 2004 00:40:18 +0100
> 
> I wanted to write some emacs lisp code to display the contents of registers,
> where I've saved several window configurations. I was thinking of a list of
> registers identified by a, b, c, ..., with, for each one, the names of the
> buffers/files displayed in each window.
> 
> Unfortunately the Elisp Manual states clearly that
> 
>        Primitives to look inside of window configurations would
>     make sense, but none are implemented.  It is not clear they
>     are useful enough to be worth implementing.
> 
> So I guess it's time to start reading that Emacs C source code, so I can add
> the primitive I need. I've found the window config functions in window.c, but
> obviously there's a lot to understand in this (big) source.

The only built-in function involved in saving the window configuration
to a register is current-window-configuration (defined on window.c),
so I'm guessing that this is the function you are talking about.  What
it does is create a C data structure whose members store various
parameters of the window configuration, then store the data structure
in a Lisp object.  A helper subroutine save_window_save is also of
interest.

To understand the details, you need to look at lisp.h that defines
the macros, such as XSETINT, XVECTOR, XSETWINDOW_CONFIGURATION, etc.

Re: Emacs C source, suggested reading order

[joao]

"Eli Zaretskii" <eliz@elta.co.il> writes:

> The only built-in function involved in saving the window configuration
> to a register is current-window-configuration (defined on window.c),
> so I'm guessing that this is the function you are talking about.  What
> it does is create a C data structure whose members store various
> parameters of the window configuration, then store the data structure
> in a Lisp object.  A helper subroutine save_window_save is also of
> interest.

Yes, that's it. What I want is to query the contents of that C structure, and
make it available as a Lisp object or through a Lisp function.

> To understand the details, you need to look at lisp.h that defines
> the macros, such as XSETINT, XVECTOR, XSETWINDOW_CONFIGURATION, etc.

Good, thanks !
Joao

-- 
João Moreira de Sá Coutinho      
(joao at teaser dot fr)