CBPCalc::frameSymbolsInDateFormat

private function frameSymbolsInDateFormat($format)
{
	$complexSymbols = ['j F', 'd F', 'jS F'];
	$symbols = ['D', 'l', 'F', 'M', 'r'];

	$frameRule = [];
	foreach ($symbols as $symbol)
	{
		$frameRule[$symbol] = '#' . $symbol . '#';
		$frameRule['\' . $symbol] = '\' . $symbol;
	}
	foreach ($complexSymbols as $symbol)
	{
		$frameRule[$symbol] = substr($symbol, 0, -1) . '#' . $symbol[-1] . '_1#';
		$frameRule['\' . $symbol] = '\' . substr($symbol, 0, -1) . '#' . $symbol[-1] . '#';
	}

	return strtr($format, $frameRule);
}