Re: getusershell: Split file by lines instead of spaces.

[Collin Funk]

Hi Bruno,

On 5/21/24 5:43 PM, Bruno Haible wrote:
> The new patch is good. OK to push.

Done, thanks.

>> Interesting way to think about it, thanks. Do you have a strong math
>> background? It has been a while since I looked at that interval
>> notation.
> 
> Oh, I learned the interval notation at school. It's really nothing fancy.

I remember seeing it in school but I don't use it enough. It was quick
to relearn using set builder notation [1]. So feel free to use it in
any future explanations. :)

> The problem with the [start,end] convention is that it cannot
> represent an empty array slice. Therefore, when you are dealing
> with a problem in which an empty array slice is a valid special
> case, [start,end] is the wrong representation.
> 
> Try to formulate a non-trivial algorithm, such as bubble sort
> or searching an item in a sorted array using binary-search.
> If you do it ad-hoc with cursors or some such, chances a high
> that you will introduce off-by-one mistakes or endless loops.
> Try it with the [start,end) convention, and you will succeed.

Good point. I'd like to think I would use [start,end) when writing
those. But better to build good habits for even simple algorithms like
this. I'll keep that in mind for the future.

I made a mess out of my /etc/shells (lots of blank lines, trailing
comments, trailing spaces, etc) and ran with Valgrind before sending
that patch. Time to clean that up now.

Collin

[1] 
https://en.wikipedia.org/wiki/Interval_(mathematics)#Including_or_excluding_endpoints