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Re: Variable references (declare -n, "nameref") are limited to a depth of 8.

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On 4/25/20 11:46 PM, Andrej Podzimek wrote:
>>> Description:
>>>
>>>   While looking for a way to share a "cache" array with a recursive function
>>>   call stack (using local -n (nameref)), I hit a well-known problem with
>>>   "circular name reference" (which has been around for a long time). 
>>
>> Yes, that's how it does loop detection.
> 
> There are, however, no loops involved in my $a … $k example; it is merely a chain of declare -n references starting from a regular variable $a. The chain breaks unexpectedly and silently after 8 links ($j and $k appear to be empty).
> 
> Better options, IMHO, would include:
> 
> (a) An unlimited number of declare -n resolution steps (as long as there are no cycles, i.e., no variable name(*) is encountered twice). This may have performance consequences when abused, but it would be better than unexpected empty values after >8 steps.
> 
> (b) An error message when trying to dereference $j or $k (links No. 9 and 10 in the chain example), saying e.g. “maximum nameref depth (8) exceeded”. This would at least make the problem obvious and easy to debug.

I would welcome patches that did either one of these things.

-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
		 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/

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Re: Variable references (declare -n, "nameref") are limited to a depth of 8. Chet Ramey <chet.ramey@case.edu> - 2020-04-27 11:42 -0400

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