On Fri, 28 Mar 2025 11:05:05 -0400, Rick Troth wrote:

>EXCELLENT observation
>
>Postel's Law should be followed
>
>https://en.wikipedia.org/wiki/Robustness_principle
>
No.  This leads to chaos.  Developers are inclined to obey the
"be liberal in what you accept" which leaves no platform on which
to validate "be conservative in what you send."

z/OS is conservative in what it accepts and I have had problems
building FOSS which was probably "validated" with the liberal gcc.
both senders and accepters whould obey the same rules, which
should be the Standard.

>Consumer systems REGULARLY have blanks in filenames, which makes
>scripted automation difficult. Other punctuation can also be troublesome.
>
Yes.  There should be extensions to scripting languages to support
utilities generating tokenized lists of filenames.

>-- R; <><


>On 3/27/25 10:52 PM, Joel Ewing wrote:
>> Saying that any 8-bit combination is "supported" in file names and
>> paths by Unix is misleading.   It would be very bad form to use a
>> character code that is not associated with a standard displayable
>> glyph, even if the creation of such a file were allowed, because
>> reliably working with a file with "invisible" characters in the name
>> after creation would be impractical. Special characters like
>> single-quote, double-quote, asterisk, question-mark, etc. may be
>> allowed, but are inadvisable because of their special semantic
>> significance when referring to files in commands and standard
>> utilities causes problems,   Any broadning of file name rules in z/OS
>> would most likely need restrictions based on usage context as well.
>>
>> What is allowed and sometimes useful in current versions of Linux and 
>> Windows is almost any other arbitrary standard Unicode glyph in  file
>> and path names, represented in UTF-8.   I would assume that multi-byte
>> characters count as that many bytes against the 255-byte limit.   You
>> can use characters in non-Latin alphabets and even use special
>> symbols, such as in the file path
>> *~/gov_SNAFU/👊🇺🇸🔥.txt , *provided all the utilities you plan to
>> use with the file support fonts that provide the appropriate glyphs
>> and the system allows you to represent Unicode characters -- in this
>> case u+270A (✊),  u+1F1FA u+1F1F8 (🇺🇸), and u+1F525 (🔥) --  by some
>> means that isn't too tedious.  Linux provides Unicode text entry
>> support globally at the Operating System level.   Windows
>> unfortunately requires that support to be provided by individual
>> applications, and not all provide it.
>>
>>     JC Ewing

-- 
gil

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