my $array_ref = [
  { foo=> 1, herp => 'a'},
  { bar => 2, derp => 'b'},
  { baz => 3, burp => 'c'},
];

# unrolled iteration loop
++$array_ref->[0]->{foo}; # now 2
++$array_ref->[0]->{herp}; # now b
++$array_ref->[1]->{bar}; # now 3
++$array_ref->[1]->{derp}; # now c
++$array_ref->[2]->{baz}; # now 4
++$array_ref->[2]->{burp}; # now d