Re: Calculate wordwrapped/justified lines using the stencil stacking primitives (issue 13827044)

[Janek Warchoł]

Hi David,

2013/9/24  <address@hidden>:
> Do you have an actual problem with how the new code is
> written in comparison to the old code?

No, not at all!  I apologize for not making my intentions clearer.  I
asked for an example not because i doubted your patch - i just wanted
to have some output to look at, so that i would understand the patch
better.  I actually haven't read the code yet - as you know, i'm not
fluent with Scheme, and i expected that i wouldn't manage to
understand the patch without having some example.  I'm sorry that my
question made you anxious.

> I sometimes have a hard time
> understanding why people object against refactoring code even when the
> old code has been prodded until it happens to turn out the correct thing
> most of the time without anybody exactly knowing why.

This situation occasionally happens to me as well, and i don't
understand it either.

> But assuming that this code would not actually fix anything but lead to
> equivalent results: would you object to it?

No, absolutely not!  I know that you're a much better programmer that
i am, so unless i'd find something explicitely suspicious (which is
unlikely) i would never object to code refactoring.

> "It works" is not the ultimate excuse for everything.  Because if no-one
> can understand _why_ it works, then even in the case that it works in
> 100% of all cases now, future changes might break it unintentionally
> when nobody can understand the reason it works.

Absolutely!

> Issue 3552 is such a case where I changed code not because of any known
> breakage, but because the risk of future breakage in connection with
> superficially unrelated and/or user code.

That's a good reason to change things.

> On 2013/09/24 07:46:17, janek wrote:
>> could you give an example of how it was failing before?
>
> Regtests change, and the new regtests seem pretty consistent.  I was not
> going to measure this out in detail.  The comments of the old code also
> spell out a failure case.  Check out
> \markuplist
> #(map (lambda (n)
>        #{ \markup
>             \override #'(line-width . 60)
>             \column {
>               \override #`(text-direction . ,(if (zero? (remainder n 2))
> RIGHT LEFT))
>               \justify { $@(map number->string (iota (quotient n 2))) }
>               \draw-hline
>             }
>        #})
>   (iota 160 60))
>
> and you'll see that the old code has problems in the patterns ending on
> 85 and 104.

Thanks, this should help me understand what's going on.
Interestingly, with current master (bfdebcb93bebe820c2d5fd6c1bed) the
pattern ending with 104 appears to be fine.

best,
Janek