The autovivification module is pretty good for this kind of thing. Offers you the ability to simply switch off autovivification, warn about it, or croak. Rather than being tied to a particular hash, it's lexically scoped. And it's context-sensitive, so you could decide that 'store' operations are allowed to autovivify, like:

{
  no autovivification qw(strict);
  use autovivification qw(store);
  my %hash;
  $hash{foo}{bar}{baz} = 1;     # autovivifies OK
  delete $hash{fool}{bar}{baz}; # dies
}

[download]

If only autovivification weren't so tricky to type.

perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'

In reply to Re^6: initialize all values in a hash by tobyink
in thread initialize all values in a hash by AWallBuilder

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