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Re: Bash-5.1-beta available

From: Chet Ramey
Subject: Re: Bash-5.1-beta available
Date: Thu, 17 Sep 2020 14:40:04 -0400
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On 9/16/20 6:45 PM, Robert Elz wrote:
>     Date:        Wed, 16 Sep 2020 11:35:41 -0400
>     From:        Chet Ramey <chet.ramey@case.edu>
>     Message-ID:  <210592e5-f42c-32ee-7c85-9418d3e2993c@case.edu>
>   | That's what gives the impression that the standards committees are a
>   | private club.
> This one isn't confined to the standards industry, it exists everywhere.
> At a particular time, in a particular community, there tends to be a
> common understanding of all kinds of things.  Different time, different
> community, and that understanding just isn't there any more.

That's why I find yash so interesting to test against. It's written by
someone with almost no contact with the standards community, yet attempts
to implement the letter of POSIX.

>   | I read it all. The hills are littered with bodies.
> Would be nice if you could delete the Reply-To your messages all
> carry, since it is (every time I have seen anyway) the same as the
> From it is useless if intended as a From replacement, and I kind of
> doubt that you always want to request that no-one reply to the list.

I don't have list-specific email configs.

>   | The problem is the standard has changed over the years, and now we all
>   | have compatibility issues dealing with past attempts to implement what
>   | ended up being a moving target.
> Yes, that is a problem.  Partly caused by trying to implement the
> standard, instead of implementing what is right, and then making sure
> the standard says what is implemented.

Because that's where the incentives are. Nobody cares if you implement
"what is right" if you fail a standards conformance test.

>   | Of course it can. It can check and throw an error if desired.
> That isn't ensuring that there are an even number of quotes, it is
> objecting when there aren't.  The two are related, but are not the
> same thing.

The  shell implementation still has to do something, even if the user is
supposed to ensure it, and that something really should try to reflect what
the user intends (determining that is always a tricky business).

> But to go back to the original issue, in a here-doc, the " is always just
> a character, it is never special, and hence a \" combination in a here doc
> (except in those cases where a new quoting context is established - which
> it isn't in a ${foo+word} expansion - never has been) should always
> generate \"

Then the standard needs to be clarified, doesn't it? Current experience
shows the wording to be ambiguous, since the world is divided into two
camps here.


``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/

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