I have come across an interesting problem:
perldoc -f exists
undef $ref;
if (exists $ref->{"Some key"}) { }
print $ref; # prints HASH(0x80d3d5c)
The documentation goes further to say:
This surprising autovivification in what does not at first--or
even second--glance appear to be an lvalue context may be fixed
in a future release.
Normally I would not care that perl is creating keys in deeply nested hashes so long as I know that
the value is undef, but if I grab a list of keys without thinking:
C:\>perl -e "undef $ref; if (exists $ref->{'key1'}->{'key2'})
{print 'I think i am okay, but...'}; print keys %{$ref}"
key1
So, is there a module out there that will control the way perl autovivifies
(kind of like AutoLoader but for variables) nested structures?
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