On 8/10/11 5:59 PM, Linda Walsh wrote:
>
> Chet Ramey wrote:
>>
>> Yes. It's a case of not saving and restoring enough state across
>> possibly-
>> recursive calls to the shell parser. (The assignment statement is the
>> key
>> in this case.)
>>
>> > So, I compared subst.c files from bash-4.1-9 and bash-4.2-10 and was
>> > able
>> > to build a patch that it seems to make it work.
>> > So to all you Bash guru's, can this patch be applied with no extra
>> > consequences ?
>>
>> No. The code is in there for a reason. It's part of the fix for
>> Posix
>> interpretation 217 (http://austingroupbugs.net/view.php?id=217).
>>
>> The right fix is to save and restore the right shell context around
>> recursive calls to the parser. The attached patch does that, and the
>> result passes the rest of the test suite (which obviously needs to be
>> augmented).
> ----
>
> Is this a fluke, due to the above changes NOT being 4.1? Or is this
> construction going to break in 4.2:
>
> '$((( )))'
What does `break' mean? It's already written in a manner more confusing
and obscure than necessary. What value do you think the extra set of
parens adds?
>
> I wanted to evaluate something and assign result to a var.
>
> so:
> a=$(((-48-16+2**6)))
> gives me 'a=0', but
And it does in bash-4.2 also, but why make things harder on yourself?
If you feel you have to use a redundant set of parens, make the intent
of the code clear:
a=$(( (-48-16+2**6) ))
> How do I assign something to a?
With an assignment statement.
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU c...@case.edu http://cnswww.cns.cwru.edu/~chet/
