features: - conversion to reverse polish notation (postfix notation) - operations: + - * / ^ ! - supported variables: x, y, e, pi; - supports implied multiplication like 7x or 2(x-4) or even 2sin(x)cos(x), but it does not work for cases like xy or xln(x) - all trigonometry and calculus functions - two-argument functions like min(x,y) or nthroot(3, x) - nested vertical bars denoting abs() function, for example in expression | |x-3| - 7 | , will be interpreted incorrectly and you should replace them with abs() like this: abs( abs(x-3) - 7 ) , other cases ( like |x| + |y| ), however, should be fine
