From: Bart Schaefer <schaefer@brasslantern.com>
To: Daniel Shahaf <d.s@daniel.shahaf.name>
Cc: Zsh hackers list <zsh-workers@zsh.org>
Subject: Re: zmathfunc: min, max, sum throw error if result equals 0
Date: Fri, 16 Apr 2021 13:05:13 -0700 [thread overview]
Message-ID: <CAH+w=7aBmf8eW8kAkKjBip70rcdCor3f-bwf1ZMeTUziw4ZJAQ@mail.gmail.com> (raw)
In-Reply-To: <20210416195028.GE15670@tarpaulin.shahaf.local2>
On Fri, Apr 16, 2021 at 12:51 PM Daniel Shahaf <d.s@daniel.shahaf.name> wrote:
>
> [...] the first one interpolates $arg as in double-quoted strings
> and then parses the string " x += 2 > result ", where the > operator has
> higher precedence, and «2 > result» evaluates to 1, and the «print» then
> evaluates everything left to right; whereas the latter sees «arg» and
> tries to evaluate that _as a number_, which works out to 2 (with a side
> effect), so the condition evaluates to true, and the assignment on the
> RHS then works out to 4 (with a side effect). Clear as a cloudless day
Given that, I'm puzzled why you did
> + (( $arg < result ))
> + case $? in
> + (0) result=$arg;;
> + (1) ;;
> + (*) return $?;;
> + esac
> done
> (( result ))
and why not
(( arg < result ))
case $? in
(0) (( result = arg ));;
(1) ;;
(*) return $?;;
esac
done
(( result ))
?? The (( $arg < result )) formulation still potentially has
different operator precedence in and out of math context, and
result=$arg followed by (( result )) still does repeat interpretation
of $arg. Why ever interpolate $arg as a string?
next prev parent reply other threads:[~2021-04-16 20:05 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-07 16:37 Nikolaus Thiel
2021-03-07 17:17 ` Daniel Shahaf
2021-03-07 21:39 ` Bart Schaefer
2021-03-07 21:56 ` Daniel Shahaf
2021-03-08 2:25 ` Bart Schaefer
2021-04-16 18:26 ` Daniel Shahaf
2021-04-16 18:47 ` Bart Schaefer
2021-04-16 19:50 ` Daniel Shahaf
2021-04-16 20:05 ` Bart Schaefer [this message]
2021-04-16 20:08 ` Daniel Shahaf
2021-04-16 18:21 ` Daniel Shahaf
2021-05-16 14:54 ` Lawrence Velázquez
2021-05-18 2:02 ` Daniel Shahaf
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