git/list[1] front-page[2] threads[3] people[4] search[5] about
 

Re: possible Improving diff algoritm

From
Javier Domingo <javierdo1@gmail.com>
Date
Dec 14, 2012, 12:20 UTC
Message-ID
<CALZVap=r0toqWT7aJxiKtezmR8s4QDd0x92JX-eBLWhKaJsmOw@mail.gmail.com>
In-Reply-To
<7vzk1izcv6.fsf@alter.siamese.dyndns.org>

I think the idea of being preferable to have a blank line at the end of the added/deleted block is key in this case.

Javier Domingo
2012/12/13 Junio C Hamano <gitster@pobox.com>:
Show 46 quoted lines
> Geert Bosch <bosch@adacore.com> writes:
>
>> It would seem that just looking at the line length (stripped) of
>> the last line, might be sufficient for cost function to minimize.
>> Here the some would be 3 vs 0. In case of ties, use the last
>> possibility with minimum cost.
>
> -- 8< --
> #ifdef A
>
> some stuff
> about A
>
> #endif
> #ifdef Z
>
> some more stuff
> about Z
>
> #endif
> -- >8 --
>
> If you insert a block for M following the existing formatting
> convention in the middle, your heuristics will pick the blank line
> after "about A" as having minimum cost, no?
>
> You inherently have to know the nature of the payload, as your eyes
> that judge the result use that knowledge when doing so, I am afraid.
> I think your "define a function that gives a good score to lines
> that are likely to be good breaking points" idea has merit, but I
> think that should be tied to the content type, most likely via the
> attribute mechanism.
>
> In any case, I consider this as a low-impact (as Michael Haggerty
> noted, it is impossible to introduce a bug that subtly break the
> output; your result is either totally borked or is correct) and
> low-hanging fruit (it can be done as a postprocessing phase after
> the xdiff machinery has done the heavy-lifting of computing LCA), if
> somebody wants to experiment and implement one.  As long as the new
> heuristics is hidden behind an explicit command line option to avoid
> other "consequences", I wouldn't discourage interested parties from
> working on it.  It is not just my itch, though.
> --
> To unsubscribe from this list: send the line "unsubscribe git" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
Previous: Junio C HamanoNext: Bernhard R. Link
Message 16 of 18 in “Fwd: possible Improving diff algoritm”
  1. KevinDec 12, 2012
  2. Junio C HamanoDec 12, 2012
  3. Brian J. MurrellDec 12, 2012
  4. KevinDec 12, 2012
  5. Junio C HamanoDec 12, 2012
  6. Morten WelinderDec 12, 2012
  7. Junio C HamanoDec 12, 2012
  8. Andrew ArdillDec 12, 2012
  9. Javier DomingoDec 12, 2012
  10. Junio C HamanoDec 12, 2012
  11. Javier DomingoDec 12, 2012
  12. Michael HaggertyDec 13, 2012
  13. Morten WelinderDec 13, 2012
  14. Geert BoschDec 13, 2012
  15. Junio C HamanoDec 13, 2012
  16. Javier DomingoDec 14, 2012
  17. Bernhard R. LinkDec 14, 2012
  18. Javier DomingoDec 15, 2012

Read the whole thread, see it on lore, or plain text.

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.