private function filterVariablesFromSelection($selectedVariables, DefinedVariables $selection, Closure $filter, $reducer)
{
$variablesUsed = array();
$compareLine = $reducer == 'max' ? $selection->endLine() : $selection->startLine();
$knownVariables = $this->all();
foreach ($selectedVariables as $variable) {
if (!isset($knownVariables[$variable])) {
continue;
}
$lastUsedLine = $reducer($knownVariables[$variable]);
if ($filter($lastUsedLine, $compareLine)) {
$variablesUsed[] = $variable;
}
}
return $variablesUsed;
}
