bug#21325: ls : feature request --width=zero

[Pádraig Brady]

On 20/10/15 03:55, Aaron Davies wrote:
> On Aug 24, 2015, at 3:34 AM, f0rhum <address@hidden> wrote:
>>
>> Le 23/08/2015 23:11, Stephane Chazelas a écrit :
>>
>>> 2015-08-23 13:26:35 +0200, Erik Auerswald:
>>>> Hi,
>>>>
>>>> On Sat, Aug 22, 2015 at 08:58:01PM -0700, Paul Eggert wrote:
>>>>> Pádraig Brady wrote:
>>>>>> Also base64 -w0 has similar meaning.
>>>>> I didn't know that, but I don't like that either.  Utilities should
>>>>> use an explicit representation for infinity, if that's what they
>>>>> need.  'Inf', say.
>>>>>
>>>>> In the meantime, the patch that I installed is helpful even if we
>>>>> later add an explicit representation of infinity.
>>>> Using 0 to disable a length or width limit is quite common with networking
>>>> gear. I do not know any example requiring a keyword like "Inf", neither
>>>> UNIX (like) nor other CLIs.
>>> [...]
>>>
>>> Anything using strtod() to parse numbers should understand inf
>>> or infinity (with any vAriATion on the case).
>>>
>>> That's the case of GNU sleep for instance.
>>>
>>> That doesn't apply to integers though.
>>
>> I'm not involved, but just a suggestion if no one thought about this: why
>> not use w-1 ?
> 
> here's some more precedent for 0 meaning infinity; from `info sed':
> 
>> `-l N'
>> `--line-length=N'
>>     Specify the default line-wrap length for the `l' command.  A
>>     length of 0 (zero) means to never wrap long lines.  If not
>>     specified, it is taken to be 70.

Right. It comes down to whether the number is considered as a length/width or a 
limit.
If a limit, then 0 naturally implies no limit. If a length, then 0 is 
meaningless.
So in cases where the output can be optionally wrapped,
IMHO it makes sense to consider 0 as a limit.

I like Bernhard's suggestion of just using `paste -s -d' '`,
however that single spaces items, whereas ls double spaces
(to aid parsing of names with spaces I suppose).

BTW I see the change to allow -w999... also allowed 0,
which results in division by zero later on:

  $ src/ls -w0 --color=always
  Floating point exception (core dumped)

The attached fixes that and makes -w0 behave as described above,
while operating more efficiently in this mode.

cheers,
Pádraig.

ls-w0.patch
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