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From: Eli Zaretskii <eliz@gnu.org>
To: Alan Mackenzie <acm@muc.de>
Cc: emacs-devel@gnu.org
Subject: Re: Edebug corrupting point in buffers; we need buffer-point and set-buffer-point, perhaps.
Date: Mon, 31 Oct 2022 16:50:52 +0200	[thread overview]
Message-ID: <83pme8dp2r.fsf@gnu.org> (raw)
In-Reply-To: <Y1/cbPASCN2E5vC3@ACM> (message from Alan Mackenzie on Mon, 31 Oct 2022 14:32:12 +0000)

> Date: Mon, 31 Oct 2022 14:32:12 +0000
> Cc: emacs-devel@gnu.org
> From: Alan Mackenzie <acm@muc.de>
> 
> Anyhow, I proposed buffer-point and set-buffer-point.  They would be a
> lot faster than set-buffer followed by point and goto-char.  Here is my
> first version of these.  What do you think?

I'm not sure performance in a debugger is a reason good enough to add
2 more primitives.  The fact that we didn't need them until now should
tell us something, no?

Stefan, Lars, WDYT?

Anyway, a couple of minor comments:

> +DEFUN ("buffer-point", Fbuffer_point, Sbuffer_point, 1, 1, 0,
> +       doc: /* Return the buffer point of BUFFER-OR-NAME.
> +The argument may be a buffer or the name of an existing buffer.  */)
> +  (Lisp_Object buffer_or_name)

Why not an optional argument to 'point'?  And why in buffer.c and not
in editfns.c?

> +  return (make_fixnum (b->pt));

Please never-ever use b->pt etc. directly.  We have BUF_PT and other
macros for that, and for a good reason.

> +  CHECK_FIXNUM_COERCE_MARKER (pos);
> +  p = XFIXNUM (pos);

This is sub-optimal: a marker holds both character and byte position,
and you lose it here.  Ignoring the byte position is only justified if
the marker belongs to the wrong buffer.

> +  if (p < b->begv) p = b->begv;
> +  if (p > b->zv) p = b->zv;

We have clip_to_bounds.  And again, always use BUF_BEGV and BUF_ZV,
not literal references to members of struct buffer.

> +  SET_PT (p);

We have SET_BUF_PT_BOTH.



  reply	other threads:[~2022-10-31 14:50 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-31 11:43 Edebug corrupting point in buffers; we need buffer-point and set-buffer-point, perhaps Alan Mackenzie
2022-10-31 13:16 ` Eli Zaretskii
2022-10-31 14:32   ` Alan Mackenzie
2022-10-31 14:50     ` Eli Zaretskii [this message]
2022-10-31 15:46       ` Alan Mackenzie
2022-10-31 17:33         ` Stefan Monnier
2022-10-31 17:55         ` Eli Zaretskii
2022-10-31 20:46           ` Alan Mackenzie
2022-11-01  6:21             ` Eli Zaretskii
2022-10-31 17:19       ` Stefan Monnier
2022-10-31 18:09         ` Eli Zaretskii
2022-10-31 20:35           ` Stefan Monnier
2022-10-31 17:21 ` Stefan Monnier
2022-10-31 18:10   ` Eli Zaretskii
2022-10-31 23:14     ` Stefan Monnier
2022-11-01  7:06       ` Eli Zaretskii
2022-10-31 21:25 ` Alan Mackenzie
2022-11-01  6:45   ` Eli Zaretskii
2022-11-01 11:41     ` Edebug corrupting point in buffers Alan Mackenzie
2022-11-01 11:53       ` Eli Zaretskii
2022-11-01 13:42         ` Alan Mackenzie
2022-11-01 14:42           ` Eli Zaretskii
2022-11-01 17:06             ` Alan Mackenzie
2022-11-01 17:12               ` Eli Zaretskii
2022-11-01 17:24                 ` Alan Mackenzie
2022-11-01 17:57                   ` Eli Zaretskii
2022-11-01 19:02                     ` Alan Mackenzie
2022-11-01 19:47                       ` Stefan Monnier
2022-11-01 20:53                         ` Alan Mackenzie
2022-11-01 21:51                           ` Stefan Monnier
2022-11-02 10:40                             ` Alan Mackenzie
2022-11-02 13:12                               ` Stefan Monnier
2022-11-02 13:28                                 ` Eli Zaretskii
2022-11-02  3:28                         ` Eli Zaretskii
2022-11-02 12:53                           ` Stefan Monnier
2022-11-02 17:40                       ` Juri Linkov
2022-11-02 18:26                         ` Eli Zaretskii
2022-11-02 18:36                           ` Juri Linkov
2022-11-02 18:52                             ` Eli Zaretskii
2022-11-03 17:25                               ` Juri Linkov
2022-11-03 18:06                                 ` Eli Zaretskii
2022-11-03 18:31                                   ` Juri Linkov
2022-11-02 11:34                     ` Alan Mackenzie
2022-11-02 14:00                       ` Eli Zaretskii
2022-11-02 16:18                         ` Alan Mackenzie
2022-11-02 16:57                           ` Eli Zaretskii
2022-11-03 11:32                             ` Alan Mackenzie
2022-11-03 13:29                               ` Eli Zaretskii
2022-11-03 18:07                                 ` Alan Mackenzie
2022-11-03 18:15                                   ` Eli Zaretskii
2022-11-03 20:25                                     ` Alan Mackenzie
2022-11-05 11:24                                       ` Eli Zaretskii
2022-11-05 16:50                                         ` Alan Mackenzie
2022-11-06  8:10                                           ` Eli Zaretskii
2022-11-06 14:40                                             ` Alan Mackenzie
2022-11-03 19:29                         ` Stefan Monnier
2022-11-03 19:36                           ` Eli Zaretskii
2022-11-03 20:39                             ` Stefan Monnier
2022-11-04  6:34                               ` Eli Zaretskii
2022-11-04  6:37                               ` Eli Zaretskii
2022-11-03 19:57                           ` Alan Mackenzie
2022-11-03 20:35                             ` Stefan Monnier

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