Re: [PATCH] Improve function dir.c:trim_trailing_spaces()

[Jeff King <peff@peff.net>]

On Thu, May 29, 2014 at 02:34:33PM -0700, Pasha Bolokhov wrote:

> > However, I doubt it makes that much of a difference in practice, so
> > unless it's measurable, I would certainly go with the version that is
> > more readable (and correct, of course).
> 
>     Sorry, just to recap, you would go with the existing version
> (which needs correction), or with the one that is being suggested? (I
> agree I can format the style a tiny bit better in the latter one)

I actually think the original left-to-right is a little easier to
follow, but I do not feel strongly. I mainly meant "argue based on
readability and correctness, do not argue based on speed".

>      Tests should not be a big problem, although it's kind of clumsy
> to test an internal function which does not really give any output
> (you can only measure the outcome). Just again to stress, I have
> tested both implementation extensively and the suggested new
> implementation gives the correct answers for all your examples below
> and all others. If I show this with explicit "t/" tests, will it
> suffice then?

Yes. I think specifically that you can extend the tests at the end of
t0008.

>     Basically what I suggest is
> 
> -- either: improve the existing function such that it does correctly
> that "text  \   " case, and also does not use 'strlen' since it anyway
> moves left to right
> 
> -- or: use the new suggested implementation (and just brush the
> formatting a bit), and perhaps borrow 'len' from the calling routine
> 
> And add tests in any case. What is the preference?

I'd be OK with either, though I have a slight preference for the first,
just because I find the "bslash ^= 1" bit of yours, while clever, a bit
hard to follow.

-Peff