Re: possible Improving diff algoritm

[Javier Domingo <javierdo1@gmail.com>]

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>:
> 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.
> --
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