<?php

interface mtgScope
{
  function findSymbol(string $name) : ?mtgMetaUnit;
}

class mtgMultiScope implements mtgScope
{
  private array $scopes = array();

  function addScope(mtgScope $scope)
  {
    $this->scopes[] = $scope;
  }

  function findSymbol(string $name) : ?mtgMetaUnit
  {
    foreach($this->scopes as $scope)
    {
      $unit = $scope->findSymbol($name);
      if($unit)
        return $unit;
    }
    return null;
  }
}