Re: bad math expression: illegal character: "

[Sebastian Gniazdowski <sgniazdowski@gmail.com>]

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Maybe a bash emulation could be added? Equal to:

    emulate zsh -o noshglob -o braceexpand -o kshglob

+ the quotes inside (( ))? emulate already accepts "bash" as the emulation
level.

On Fri, 19 Jun 2020 at 08:39, Lawrence Velázquez <vq@larryv.me> wrote:

> > On Jun 18, 2020, at 7:19 AM, Mikael Magnusson <mikachu@gmail.com> wrote:
> >
> >> On 6/18/20, Bart Schaefer <schaefer@brasslantern.com> wrote:
> >>
> >>> On Fri, Jun 5, 2020 at 2:02 PM Lawrence Velázquez <vq@larryv.me>
> wrote:
> >>>
> >>>> On Jun 5, 2020, at 2:18 PM, Artur Renault <
> Artur.Renault@microsoft.com>
> >>>>
> >>>> while (( "$#" )); do
> >>>>
> >>>> repro.sh:1: bad math expression: illegal character: "
> >>>
> >>> For what it's worth, dash also rejects this. I assume that it and
> >>> zsh are just more strict about what constitutes a math expression.
> >>
> >> Does anybody know if this is something we should change for sh
> >> emulation, or is it merely another unspecified POSIX corner-case?
> >
> > If this is a POSIX requirement, it must have been very specific about
> > when quotes should be allowed (bash):
> >
> > $ (( "0" )); echo $?
> > 1
> > $ echo $(( "0" ))
> > bash: "0" : syntax error: operand expected (error token is ""0" ")
>
> Looks like the bash behavior changed at some point?
>
>     % /bin/bash --version | head -n 1
>     GNU bash, version 3.2.57(1)-release (x86_64-apple-darwin18)
>     % /bin/bash -c '(( "0" )); echo $?'
>     1
>     % /bin/bash -c 'echo $(( "0" ))'
>     /bin/bash: "0" : syntax error: operand expected (error token is ""0" ")
>
>     % /opt/local/bin/bash --version | head -n 1
>     GNU bash, version 5.0.17(1)-release (x86_64-apple-darwin18.7.0)
>     % /opt/local/bin/bash -c '(( "0" )); echo $?'
>     1
>     % /opt/local/bin/bash -c 'echo $(( "0" ))'
>     0
>
> Anyway, unless I'm missing something, POSIX seems pretty clear about
> this, as far as $((...)) goes:
>
>     The expression shall be treated as if it were in double-quotes,
>     except that a double-quote inside the expression is not treated
>     specially. The shell shall expand all tokens in the expression
>     for parameter expansion, command substitution, and **quote
>     removal**. [Emphasis mine.]
>
>     Next, the shell shall treat this as an arithmetic expression
>     and substitute the value of the expression.
>
>
> https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_04
>
> vq



-- 
Sebastian Gniazdowski
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