OT: Bash arrays & indirection?

[Patrick Lists]

On 16-02-12 12:13, Ian Malone wrote:
> On 16 February 2012 08:43, Patrick Lists<fedora-list at puzzled.xs4all.nl>  wrote:
>> Hi,
>>
>> I am trying to do the following in bash:
>>
>> OPTIONS = ( alfa beta gamma )
>> SUBOPTIONS_alfa = ( alfa0 alfa1 )
>> count=0
>> SETCOUNT = ${#SUBOPTIONS_${OPTIONS[$count]}[@]}
>>
>> The SETCOUNT line gives a substitution error. I would like the
>> ${OPTIONS[$count]} to be substituted with alfa so SETCOUNT is:
>>
>> SETCOUNT = ${#SUBOPTIONS_alfa[@]} which should equal 2.
>>
>> Anyone have an idea how I can make this work? Quick and dirty is fine. I
>> have already been told that it should be done differently. I appreciate that
>> but right now I just want to make it work.
>>
>
> Pushing the limits of what can be done with bash, it's just about
> possible. As you mention this is the point you should consider
> translating to another language. Anyway...
>
> http://stackoverflow.com/questions/4582137/bash-indirect-array-addressing

I missed that one. Good link.

> Also N.B. shouldn't be any spaces around those equals signs in your example.
>
> OPTIONS=( alfa beta gamma )
> SUBOPTIONS_alfa=( alfa0 alfa1 )
> SUBOPTIONS_beta=( beta_1 )
> SUBOPTIONS_gamma = ( gamma_1 gamma_2 gamma_3 )
> count=0
> #then...
> for count in {0..2} ; do
> nameSUBOPTS=SUBOPTIONS_${OPTIONS[$count]}[@]
> tmpARR=(${!nameSUBOPTS}) #You need tmpARR, because the '#' expansion
> wont work with '!'
> SETCOUNT=${#tmpARR[@]}
> echo ${OPTIONS[$count]}:$SETCOUNT
> done

Thanks! I will try it out. It looks more sane that what I found myself 
which apparently is challenging the bash gods to unleash their wrath if 
I use it:

eval SETCOUNT=\${#SUBOPTIONS_${OPTIONS[$count]}[@]}

> Finally, it's spelt 'alpha' ;)

Heh spelt or spelled? :) Actually I was thinking about the cars but 
thought alfa bentley corvette was lame so went with alfa beta and gamma.

Thank you for helping out.

Cheers,
Patrick