From: Junio C Hamano <gitster@pobox.com>
To: Stefan Beller <sbeller@google.com>
Cc: peff@peff.net, git@vger.kernel.org, jacob.keller@gmail.com,
mhagger@alum.mit.edu
Subject: Re: [PATCH] diff compaction heuristic: favor shortest neighboring blank lines
Date: Thu, 16 Jun 2016 13:27:49 -0700 [thread overview]
Message-ID: <xmqqlh24516i.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <20160616174620.1011-1-sbeller@google.com> (Stefan Beller's message of "Thu, 16 Jun 2016 10:46:20 -0700")
Stefan Beller <sbeller@google.com> writes:
> + def bal
> + do_bal_stuff()
> +
> + common_ending()
> + end
> +
> def baz
> do_baz_stuff()
>
> common_ending()
> end
>
> whereas before we had:
>
> WIP (TODO: ask peff to provide an example that actually triggers, I seem to be
> unable to write one, though I thought the above was one)
>
>
> The way we do it, is by inspecting the neighboring lines and see how
> much indent there is and we choose the line that has the shortest amount
> of blanks in the neighboring lines.
> ...
> because there is less space between line start and {end, def bal}
> than for {do_bal_stuff, common_ending}.
I haven't thought this carefully yet, but would this equally work
well for Python, where it does not have the "end" or does the lack
of "end" pose a problem? You'll still find "def bal" is a good
boundary (but you cannot tell if it is the beginning or the end of a
block, unless you understand the language), though.
> +static unsigned int leading_blank(const char *line)
> +{
> + unsigned int ret = 0;
> + while (*line) {
> + if (*line == '\t')
> + ret += 8;
This will be broken with a line with space-before-tab whitespace
breakage, I suspect...
> + else if (*line == ' ')
> + ret ++;
> + else
> + break;
> + line++;
> + }
> + return ret;
> +}
> +
> +static unsigned int surrounding_leading_blank(xrecord_t **recs, long ix,
> + long flags, long nrec)
> +{
> + unsigned int i, ret = UINT_MAX;
> + if (ix > 0)
> + ret = leading_blank(recs[ix - 1]->ptr);
> + if (ix < nrec - 1) {
> + i = leading_blank(recs[ix + 1]->ptr);
> + if (i < ret)
> + ret = i;
> + }
> + return ret;
> +}
> +
> static int recs_match(xrecord_t **recs, long ixs, long ix, long flags)
> {
> return (recs[ixs]->ha == recs[ix]->ha &&
> @@ -416,7 +445,7 @@ static int recs_match(xrecord_t **recs, long ixs, long ix, long flags)
> int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) {
> long ix, ixo, ixs, ixref, grpsiz, nrec = xdf->nrec;
> char *rchg = xdf->rchg, *rchgo = xdfo->rchg;
> - unsigned int blank_lines;
> + unsigned int blank_lines, min_bl_neigh_indent;
> xrecord_t **recs = xdf->recs;
>
> /*
> @@ -451,6 +480,7 @@ int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) {
> do {
> grpsiz = ix - ixs;
> blank_lines = 0;
> + min_bl_neigh_indent = UINT_MAX;
>
> /*
> * If the line before the current change group, is equal to
> @@ -485,7 +515,13 @@ int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) {
> * the group.
> */
> while (ix < nrec && recs_match(recs, ixs, ix, flags)) {
> - blank_lines += is_blank_line(recs, ix, flags);
> + if (is_blank_line(recs, ix, flags)) {
> + unsigned int bl_neigh_indent =
> + surrounding_leading_blank(recs, ix, flags, nrec);
> + if (min_bl_neigh_indent > bl_neigh_indent)
> + min_bl_neigh_indent = min_bl_neigh_indent;
> + blank_lines++;
> + }
>
> rchg[ixs++] = 0;
> rchg[ix++] = 1;
> @@ -525,6 +561,7 @@ int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) {
> if ((flags & XDF_COMPACTION_HEURISTIC) && blank_lines) {
> while (ixs > 0 &&
> !is_blank_line(recs, ix - 1, flags) &&
> + surrounding_leading_blank(recs, ix - 1, flags, nrec) > min_bl_neigh_indent &&
> recs_match(recs, ixs - 1, ix - 1, flags)) {
> rchg[--ixs] = 1;
> rchg[--ix] = 0;
next prev parent reply other threads:[~2016-06-16 20:27 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-16 17:46 [PATCH] diff compaction heuristic: favor shortest neighboring blank lines Stefan Beller
2016-06-16 20:27 ` Junio C Hamano [this message]
2016-06-16 21:06 ` Stefan Beller
2016-06-16 21:10 ` Michael Haggerty
2016-06-16 21:36 ` Stefan Beller
2016-06-17 15:36 ` Jeff King
2016-06-17 16:09 ` Stefan Beller
2016-06-23 17:10 ` Michael Haggerty
2016-06-23 17:25 ` Stefan Beller
2016-06-23 17:37 ` Junio C Hamano
2016-06-23 20:13 ` Michael Haggerty
2016-06-30 13:54 ` Michael Haggerty
2016-07-01 17:04 ` diff heuristics dramatically improved by considering line indentation and " Michael Haggerty
2016-07-01 18:01 ` [PATCH] diff compaction heuristic: favor shortest neighboring " Junio C Hamano
2016-07-04 14:33 ` Jakub Narębski
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: http://vger.kernel.org/majordomo-info.html
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=xmqqlh24516i.fsf@gitster.mtv.corp.google.com \
--to=gitster@pobox.com \
--cc=git@vger.kernel.org \
--cc=jacob.keller@gmail.com \
--cc=mhagger@alum.mit.edu \
--cc=peff@peff.net \
--cc=sbeller@google.com \
/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://80x24.org/mirrors/git.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).