On Thu, Jul 25, 2013 at 12:29 AM, David Korn <[email protected]> wrote:
> cc: [email protected] [email protected]
> Subject: Re: Re: [ast-developers] [RFE] var.__ to access the parent variable
> of a type or compound variable
> --------
>
>
>> I like the idea of var.__ because it has a lot of potential. IMO, in
>> terms of usefulness, its 2nd to namerefs.
>>
>> Irek
>>
>
> Are you proposing that for compound variables
> print ${var.__}
> be equivalent to
>
> nameref name=${var%.*}
> print ${name}
>
> Is this correct?
Yes, I think so. It eludes me at the moment why ${var%.*} only removes
the last element in a compound tree name, but...
>
> What is ${var.__} for simple variables,
simple variables => throw an error, except if they are member of a
compound variable. Then the name of the parent variable should be
printed.
> type variables
Example 1:
typeset -T my_t=(
integer a=1;
)
my_t v;
v.a.__ will refer to v itself (circular, I know, just for demonstration)
Example 2:
typeset -T my_t=(
compound a=(
integer b=1;
)
)
my_t v;
v.a.b.__ will refer to v.a, v.a.b.__.__ will refer to v
Example 3:
typeset -T my_t=(
compound a=(
integer b=1;
)
)
compound c
my_t c.v;
nameref v=c.v
v.__ will refer to c
Example 4 - the IMO important one:
typeset -T my_t=(
compound a=(
integer b=1;
)
)
function add_i
{
nameref parent_of_v=$1.__
integer parent_of_v.i=9
}
compound c
my_t c.v;
add_i c.v
print ${c.i}
should print '9'
> and for array variables?
This is the tough little question I don't have an answer for.
Irek
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