Re: "temp" vs "my"
What you want is OUTER ...
my $v = "original";
> {
> my $v = OUTER::<$v>;
> say $v;
> $v = "new one";
> say $v;
> }
> say $v;
It's how you access the outer scope from an inner scope.
-Scott
On Wed, Oct 3, 2018 at 1:10 AM yary wrote:
> Reading and playing with https://docs.perl6.org/routine/temp
>
> There's an example showing how temp is "dynamic" - that any jump outside a
> block restores the value. All well and good.
>
> Then I thought, what if I want a lexical temporary value- then use "my"-
> and this is all well and good:
>
> my $v = "original";
> {
> my $v = "new one";
> start {
> say "[PROMISE] Value before block is left: `$v`";
> sleep 1;
> say "[PROMISE] Block was left while we slept; value is still `$v`";
> }
> sleep ½;
> say "About to leave the block; value is `$v`";
> }
> say "Left the block; value is now `$v`";
> sleep 2;
>
> Then I thought, well, what if I want to initialize the inner $v with the
> outer $v.
>
> my $v = "original";
> {
> my $v = $v; # "SORRY! Cannot use variable $v in declaration to
> initialize itself"
> say "inner value is $v";
> $v= "new one";
> ...
>
> Gentle reader, how would you succinctly solve this contrived example?
> Anything you like better than this?
>
> my $v = "original";
> given $v -> $v is copy {
> say "inner value is $v"; # "original", good
> $v= "new one";
>
>
> -y
>
Re: "temp" vs "my"
Note that OUTER::<$v> only goes up one level.
So to go up two levels OUTER::OUTER::<$v>
There is also OUTERS::<$v> which will go up as many levels as it needs
to find the variable
{
my $a = 1;
my $b = 2;
{
my $a = 3;
{
say OUTER::<$a>; # 3
say OUTER::OUTER::<$a>; # 1
say OUTERS::<$a>; # 3 # only one level
say OUTERS::<$b>; # 2 # two levels
}
}
}
On Wed, Oct 3, 2018 at 10:31 AM yary wrote:
>
> Thanks! Knew I'd seen the concept of OUTER but couldn't remember the keyword.
>
> -y
>
> On Wed, Oct 3, 2018 at 5:51 AM, Timo Paulssen wrote:
>>
>> you can refer to the outer $v as OUTER::('$v'), that ought to help :)
>>
>> On 03/10/2018 08:10, yary wrote:
>>
>> Reading and playing with https://docs.perl6.org/routine/temp
>>
>> There's an example showing how temp is "dynamic" - that any jump outside a
>> block restores the value. All well and good.
>>
>> Then I thought, what if I want a lexical temporary value- then use "my"- and
>> this is all well and good:
>>
>> my $v = "original";
>> {
>> my $v = "new one";
>> start {
>> say "[PROMISE] Value before block is left: `$v`";
>> sleep 1;
>> say "[PROMISE] Block was left while we slept; value is still `$v`";
>> }
>> sleep ½;
>> say "About to leave the block; value is `$v`";
>> }
>> say "Left the block; value is now `$v`";
>> sleep 2;
>>
>> Then I thought, well, what if I want to initialize the inner $v with the
>> outer $v.
>>
>> my $v = "original";
>> {
>> my $v = $v; # "SORRY! Cannot use variable $v in declaration to
>> initialize itself"
>> say "inner value is $v";
>> $v= "new one";
>> ...
>>
>> Gentle reader, how would you succinctly solve this contrived example?
>> Anything you like better than this?
>>
>> my $v = "original";
>> given $v -> $v is copy {
>> say "inner value is $v"; # "original", good
>> $v= "new one";
>>
>>
>> -y
>
>
Re: "temp" vs "my"
Thanks! Knew I'd seen the concept of OUTER but couldn't remember the
keyword.
-y
On Wed, Oct 3, 2018 at 5:51 AM, Timo Paulssen wrote:
> you can refer to the outer $v as OUTER::('$v'), that ought to help :)
> On 03/10/2018 08:10, yary wrote:
>
> Reading and playing with https://docs.perl6.org/routine/temp
>
> There's an example showing how temp is "dynamic" - that any jump outside a
> block restores the value. All well and good.
>
> Then I thought, what if I want a lexical temporary value- then use "my"-
> and this is all well and good:
>
> my $v = "original";
> {
> my $v = "new one";
> start {
> say "[PROMISE] Value before block is left: `$v`";
> sleep 1;
> say "[PROMISE] Block was left while we slept; value is still `$v`";
> }
> sleep ½;
> say "About to leave the block; value is `$v`";
> }
> say "Left the block; value is now `$v`";
> sleep 2;
>
> Then I thought, well, what if I want to initialize the inner $v with the
> outer $v.
>
> my $v = "original";
> {
> my $v = $v; # "SORRY! Cannot use variable $v in declaration to
> initialize itself"
> say "inner value is $v";
> $v= "new one";
> ...
>
> Gentle reader, how would you succinctly solve this contrived example?
> Anything you like better than this?
>
> my $v = "original";
> given $v -> $v is copy {
> say "inner value is $v"; # "original", good
> $v= "new one";
>
>
> -y
>
>
Re: "temp" vs "my"
you can refer to the outer $v as OUTER::('$v'), that ought to help :)
On 03/10/2018 08:10, yary wrote:
> Reading and playing with https://docs.perl6.org/routine/temp
>
> There's an example showing how temp is "dynamic" - that any jump
> outside a block restores the value. All well and good.
>
> Then I thought, what if I want a lexical temporary value- then use
> "my"- and this is all well and good:
>
> my $v = "original";
> {
> my $v = "new one";
> start {
> say "[PROMISE] Value before block is left: `$v`";
> sleep 1;
> say "[PROMISE] Block was left while we slept; value is still
> `$v`";
> }
> sleep ½;
> say "About to leave the block; value is `$v`";
> }
> say "Left the block; value is now `$v`";
> sleep 2;
>
> Then I thought, well, what if I want to initialize the inner $v with
> the outer $v.
>
> my $v = "original";
> {
> my $v = $v; # "SORRY! Cannot use variable $v in declaration to
> initialize itself"
> say "inner value is $v";
> $v= "new one";
> ...
>
> Gentle reader, how would you succinctly solve this contrived example?
> Anything you like better than this?
>
> my $v = "original";
> given $v -> $v is copy {
> say "inner value is $v"; # "original", good
> $v= "new one";
>
>
> -y
