Validate a PHP array against a schema to ensure all desired keys are present (supports nested)

validateAgainstSchema.php

function validateAgainstSchema(array $schema, $data) {
  $valid = true;
  $done = false;
  
  $path = "";
  
  $current = each($schema);
  
  while($valid !== false && $current !== false) {
    list($key, $value) = $current;

    $index = is_string($key) ? $key : $value;
    $valid = isset($data[$index]);
    
    $path = $index;
    
    if ($valid && is_array($value)) {
      list($valid, $index) = validateAgainstSchema($value, $data[$key]);
      $path .= ".$index";
    }

    if ($valid) $current = each($schema);
  }
  
  return [ $valid, $valid ? "" : $path ];
}

Nice gist but I'll just leave here an array to add some complexity to the matter:

[
  "list_number" => 1,
  "items" => [[ "value" => 1552.22 ], [ "value" => 155.22 ]],
  "total" => 33
]

The items should be more JSON, like {[],[],...,[]} but I think my point is clear.
Thanks for reading ^~^