From: Stefan Monnier <monnier@IRO.UMontreal.CA>
To: Alan Mackenzie <acm@muc.de>
Cc: emacs-devel@gnu.org
Subject: Re: Thoughts on getting correct line numbers in the byte compiler's warning messages
Date: Tue, 06 Nov 2018 15:04:51 -0500 [thread overview]
Message-ID: <jwva7mmyol9.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <20181106191532.GC4030@ACM> (Alan Mackenzie's message of "Tue, 6 Nov 2018 19:15:32 +0000")
>> > Many of the original forms produced by the reader survive these
>> > transformations.
>> Yeah, that's why I thought of using a hash-table.
> What I tried before (about two years ago) was having each
> reader-produced form as a key, and the source position as a value. Each
> time the source was transformed, the new form became a new key, and the
> value stayed the same.
>
> I vaguely remember this being slow.
Which part do you remember being slow (e.g. just performing a `read`
that returns a sexp and fills that table along the way)?
> Maybe it would be better the other way around. The source position
> would be the key, and the value would be a list of (equivalent) forms.
> Building this table would be faster.
I don't follow you: why would this be faster?
> Finding a form in that table for a warning message would be much
> slower, but that shouldn't matter.
It could matter, but yeah, let's not worry about that for now.
> In byte-compile-warn, if we can't find the current form in the above
> table, we search for the containing form, get its source offset, put
> point there and read the next N forms, moving forward in the source text
> to the position we need. That this might be slow (I don't really think
> it would be) is again unimportant.
I lost you here as well: how is the location data propagated from the
reader to the byte-compiler's phase that ends up running
byte-compile-warn? I mean, how is the location info
preserved while going through macro-expansion, closure-conversion,
and byte-optimize-form? Or are most objects left untouched in practice?
I guess we could limit the info (e.g. stored in a hash-table) to map
"first cons-cell in a list" to its location info, and then change
macroexp.el, cconv.el, and friends to preserve this info as much as
possible (we may even come up with a `with-location-data` macro that
encapsulates most of the work so the changes are easy to apply).
Is that what you're thinking of?
Stefan
next prev parent reply other threads:[~2018-11-06 20:04 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-01 17:59 Thoughts on getting correct line numbers in the byte compiler's warning messages Alan Mackenzie
2018-11-01 22:45 ` Stefan Monnier
2018-11-05 10:53 ` Alan Mackenzie
2018-11-05 15:57 ` Eli Zaretskii
2018-11-05 16:51 ` Alan Mackenzie
2018-11-06 4:34 ` Herring, Davis
2018-11-06 8:53 ` Alan Mackenzie
2018-11-06 13:56 ` Stefan Monnier
2018-11-06 15:11 ` Alan Mackenzie
2018-11-06 16:29 ` Stefan Monnier
2018-11-06 19:15 ` Alan Mackenzie
2018-11-06 20:04 ` Stefan Monnier [this message]
2018-11-07 12:35 ` Alan Mackenzie
2018-11-07 17:11 ` Stefan Monnier
2018-11-07 17:00 ` Alan Mackenzie
2018-11-07 17:25 ` Stefan Monnier
2018-11-07 18:47 ` Alan Mackenzie
2018-11-07 19:12 ` Stefan Monnier
2018-11-08 14:08 ` Alan Mackenzie
2018-11-08 17:02 ` Stefan Monnier
2018-11-08 22:13 ` Alan Mackenzie
2018-11-11 12:59 ` Alan Mackenzie
2018-11-11 15:53 ` Eli Zaretskii
2018-11-11 20:12 ` Alan Mackenzie
2018-11-11 20:47 ` Stefan Monnier
2018-11-12 3:30 ` Eli Zaretskii
2018-11-12 16:19 ` Eli Zaretskii
2018-11-12 14:16 ` Alan Mackenzie
2018-11-12 15:44 ` Alan Mackenzie
2018-11-12 20:36 ` Stefan Monnier
2018-11-12 21:35 ` Alan Mackenzie
2018-11-14 13:34 ` Stefan Monnier
2018-11-15 16:32 ` Alan Mackenzie
2018-11-15 18:01 ` Stefan Monnier
2018-11-16 14:14 ` Alan Mackenzie
2018-11-08 4:47 ` Michael Heerdegen
2018-11-08 11:07 ` Alan Mackenzie
2018-11-09 2:06 ` Michael Heerdegen
2018-11-10 10:59 ` Alan Mackenzie
2018-11-10 13:20 ` Stefan Monnier
2018-11-11 7:56 ` Michael Heerdegen
2018-11-08 13:45 ` Stefan Monnier
2018-11-09 3:06 ` Michael Heerdegen
2018-11-09 16:15 ` Stefan Monnier
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: https://www.gnu.org/software/emacs/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=jwva7mmyol9.fsf-monnier+emacs@gnu.org \
--to=monnier@iro.umontreal.ca \
--cc=acm@muc.de \
--cc=emacs-devel@gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.savannah.gnu.org/cgit/emacs.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).