simple calculator

simpleCalculator.php

<?php

(new class {
	const SCALE = 14;

	public function __invoke()
	{
		while(true)	{
			$i = $this->parseFloat(readline("number: "));
			$operator = trim(readline("operator: "));
			$i2 = $this->parseFloat(readline("number: "));

			$fResult = $this->calculate($i, $operator, $i2);
			
			$sSum = is_numeric($fResult) ? "{$i} {$operator} {$i2} = " : '';

			$this->clr();
			echo sprintf("answer: %s%s\n\n", $sSum, is_numeric($fResult) ? number_format($fResult, 2) : $fResult);
		}
	}

	/**
	 * parse
	 *
	 * @param string $i
	 * @return string
	 */
	public function parseFloat($i)
	{
		return str_replace(',', '.', trim($i));
	}

	/**
	 * do calculation
	 *
	 * @param int|float $i
	 * @param string $op
	 * @param int|float $i2
	 * @return string
	 */
	public function calculate($i, $op, $i2)
	{
		switch ($op) {
			case '+':
				return round(bcadd($i, $i2, self::SCALE), 2);
			case '*':
				return round(bcmul($i, $i2, self::SCALE), 2);
			case '-':
				return round(bcsub($i, $i2, self::SCALE), 2);
			case '/':
				if ($i2 == 0) {
					return 'can\'t divide zero';
				}

				return round(bcdiv($i, $i2, self::SCALE), 2);

			case '^':
				return round(pow($i, $i2), 2);
			
			default:
				return "{$op} not supported";
		}
	}

	/** @return self */
	public function clr()
	{
		echo chr(27).chr(91).'H'.chr(27).chr(91).'J';

		return $this;
	}
})();
die("\n");