Functional PHP with a little OOP aid

functional.php

<?php

// Node[] -> (map) -> NodeTranslation[] -> (map) -> Category[] -> slice

// Purely „functional” PHP:
$parents = array_slice(array_map(function (NodeTranslation $nt) 
{
  return new Category($nt->getTitle(), $nt->getNode()->getId(), $nt->getSlug());
}, array_map(function (Node $node) 
{
  return $node->getNodeTranslations()->first();
}, $node->getParents())), 1);

// using iterators instead:
$parents = (new ArrayCollection($node->getParents()))->map(function (Node $node) 
{
  return $node->getNodeTranslations()->first();
})->map(function (NodeTranslation $nt) 
{
    return new Category($nt->getTitle(), $nt->getNode()->getId(), $nt->getSlug());
})->slice(1);

// how it should be done:

$parents = $node->getParents()
  ->map(function (Node $node) -> $node->getNodeTranslations()->first())
  ->map(function (NodeTranslation $nt) -> new Category($nt->getTitle(), $nt->getNode()->getId(), $nt->getSlug()))
  ->slice(1)