Twig extension method to add a filter that formats currency similarly to the number_format filter, but with a few changes.

currency_format.php

<?php
  /**
	 * Basically a currency replacement for number_format
	 *
	 * Big differences are
	 *
	 * @param int $amount
	 * @param int $decimal Number of decimal places
	 * @param string $decimalPoint What to use as the decimal point
	 * @param string
	 * @param string $currency Symbol ($) of currency
	 */
	public function currency_format($amount, $decimal = 2, $decimalPoint = '.', $thousandSep = ',', $symbol = "$", $negativeParenthesis = true)
	{
		$working_amount = $amount;
		if ($negativeParenthesis !== false) {
			$working_amount = abs($working_amount);
		}

		$working_amount = number_format((float) $working_amount, $decimal, $decimalPoint, $thousandSep);
		$return = "{$symbol}$working_amount";

		return $negativeParenthesis !== false && $amount < 0 ? "($return)" : $return;
	}