[tz] Tab/Space Formatting Inconsistency - Asia Ver 2023c

Brian Inglis Brian.Inglis at Shaw.ca
Wed Dec 13 02:11:55 UTC 2023

On 2023-12-12 18:46, Paul Gilmartin via tz wrote:
> On 12/12/23 17:25:15, Paul Eggert via tz wrote:
>>     ...
>> As Alois writes, this is merely a visual appearance issue; it doesn't affect 
>> the meaning of the data.

> Sometimes it matters.  "make" requires build rules to be introduced
> by tabs. not spaces.  And I know a couple lexical analyzers which
> recognize spaces but not tabs as separating tokens.

>> Spaces are sometimes used instead of tabs, when using a tab would cause 
>> columns or lines to not fit. For example, consider the line:
>>     ...
>> Rule EgyptAsia    1957    only    -    May    10    0:00    1:00    S
>>     ...
>> We prefer data to be 80 character columns or less for the usual reasons; see, 
>> for example <https://www.emacswiki.org/emacs/EightyColumnRule>. So we use a 
>> space instead of a tab there.

> Which says,
>      “Thou shalt not cross 80 columns in thy file” originated from
>      IBM 80 column punch cards, ...
> On IBM 80 column punch cards, the tab, 0x05 (rarely used), occupies
> only a single column, regardless of its appearance on output devices.

ITYM ...tab, 12-9-5 (EBCDIC 0x05 - rarely used),...

...I would go so far as to say never used except perhaps internally in software.

Take care. Thanks, Brian Inglis              Calgary, Alberta, Canada

La perfection est atteinte                   Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter  not when there is no more to add
mais lorsqu'il n'y a plus rien à retirer     but when there is no more to cut
                                 -- Antoine de Saint-Exupéry

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