Re: Fix exit status of expr version of as_func_arith.

[Eric Blake]

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According to Ralf Wildenhues on 11/16/2008 2:22 PM:
>> $ echo $((+))
>> bash: +: syntax error: operand expected (error token is "+")
>> $ echo $?
>> 0
>>
>> so we can't really make as_func_arith a reliable way to detect ill-formed
>> input.
> 
> Hmm, bash 3.2.39 here does, as does zsh 4.3.6.  OTOH, pdksh doesn't
> output an error neither change the status.

I spoke a bit too soon.  Bash _does_ set $?, but fails to set $PIPESTATUS
(I have $PIPESTATUS in my PS1, and it is annoying when the two disagree).
 So although my claim was false about $?, I was correct that bash has a bug.

$ PS1='${PIPESTATUS[*]} \$ '
0 $ echo $?
0
0 $ echo $((+))
bash: +: syntax error: operand expected (error token is "+")
0 $ echo $?
1
0 $ false
1 $

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
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