src/LuaScriptBuilder.php
private function addColumn($column, &$columns)
    {
        if (isset($columns[$column])) {
            return $columns[$column];
        }
        $name = 'c' . preg_replace("/[^a-z]+/i", "", $column) . count($columns);

        return $columns[$column] = $name;
    }
private function addColumn($column, &$columns)
    {
        if (isset($columns[$column])) {
            return $columns[$column];
        }
        $name = 'c' . preg_replace("/[^a-z]+/i", "", $column) . count($columns);

        return $columns[$column] = $name;
    }
Adds a column to the list of columns to retrieve and creates an alias
@param string $column the column name to add
@param array $columns list of columns given by reference
@return string the alias generated for the column name