src/Numbers/Number.php
public function localeFormat($decPoint = null, $separator = null)
    {
        if (!isset($decPoint) || !isset($separator)) {
            $locale = localeconv();

            if (!isset($decPoint))
                $decPoint = $locale["decimal_point"];

            if (!isset($separator))
                $separator = $locale["thousands_sep"];
        }

        return $this->format($decPoint, $separator);
    }
public function localeFormat($decPoint = null, $separator = null)
    {
        if (!isset($decPoint) || !isset($separator)) {
            $locale = localeconv();

            if (!isset($decPoint))
                $decPoint = $locale["decimal_point"];

            if (!isset($separator))
                $separator = $locale["thousands_sep"];
        }

        return $this->format($decPoint, $separator);
    }
This is the same of format(), only that it will fallback to machine locale values
when some argument is missing.

@param string|null $decPoint
@param string|null $separator
@return string