Re: [Help-bash] declare -i

[Chet Ramey]

On 5/9/12 4:55 PM, Greg Wooledge wrote:
> On Wed, May 09, 2012 at 02:43:31PM -0600, Bill Gradwohl wrote:
>> Nope. Wasn't aware of it. Thank You for the education.
> 
> Math contexts do an infinitely-recursing indirect parameter expansion
> thingy:
> 
> imadev:~$ a=b b=c c=d d=e e=f f=42; echo $((a))
> 42
> 
> And there seems to be a weird difference between these two that I don't
> fully understand:
> 
> (with a, b, c, d, e, f still defined as above)
> 
> imadev:~$ unset x
> imadev:~$ declare -i -a x=(a); echo "$x"
> a
> 
> imadev:~$ unset x
> imadev:~$ declare -i -a x; x=(a); echo "$x"
> 42
> 
> Based on the previous messages in this thread, I guess this happens
> because in the first one, the (a) is evaluated as a list of strings
> (since the evaluation occurs before the array has been made "-i"??),
> while in the second one, (a) is evaluated as a list of math contexts,
> since it's being assigned to a "-i" array.  I could be mistaken.

Pretty close, I'd bet.  Without checking the code (too many meetings this
afternoon), I'd say that attribute assignment is deferred until after the
value assignment so that `declare -r foo=bar' works.

Chet
-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU    address@hidden    http://cnswww.cns.cwru.edu/~chet/