CODEWITHSUNDEEP
perlautovivification
Eugen Konkov
Eugen Konkov

Reputation: 25133

Why perl autovivification does not work for ->@* but ->@[0] does?

I may get values by slicing:

($x, $y, $z) =  $hash->{ key }->@[0,1,2]

Why I can not to write?

($x, $y, $z) =  $hash->{ key }->@*

For second expression in cases when key is not defined in hash I get error:

Can't use an undefined value as an ARRAY reference at ...

Upvotes: 2

Views: 141

Answers (1)

ysth
ysth

Reputation: 98398

A slice gets you lvalues (writable scalars) for each index specified; a list context array dereference doesn't make any lvalues. And the general rule is that autovivification only applies with lvalues.

For example ->@* will autovivify in this case:

push $hash->{ key }->@*, 1;

Upvotes: 5

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