Re: quick question about hash element access

[tilly]

Sorry, basically you have to do it recursively or using eval. For a miniscule efficiency gain you can use tail-optimization to turn the recursion into iteration like so:

sub nested_lookup {
  my $node = shift;
  while (ref($node) and @_) {
    $node = $node->{ shift(@_) };
  }
  return @_ ? undef : $node;
}

and you would call it like this:

my $elem = nested_lookup(\%hash, split /\./, 'a.b.c.d');

(Note: could benefit from more error checking.)

[Chmrr]

And with very few changes you can make it an lvalue, so you can use it to assign to:

sub nested : lvalue {
  @_ == 1
   ? $_[0]
   : nested($_[0]{$_[1]}, @_[2..$#_]);
}

..and now you can say:

nested(\%hash, a => b => c =>) = "VALUE";

TThis can lead to such fun looking constructs as nested $hashref, a => b => c => d => = 42; Note that this code will only work under perl 5.6.0 or later, though; earlier perls had more restricted definitions of lvalues. See also descending a tree of hash references.

perl -pe '"I lo*`+$^X$\"$]!$/"=~m%(.*)%s;$_=$1;y^`+*^e v^#$&V"+@( NO CARRIER'