rpncalc_eval
Evaluates a Reverse Polish Notation (postfix) expression: whitespace-separated tokens, each a number or an operator/function that pops its operands off a stack and pushes the result. Supports arithmetic, exponentiation/modulo, roots, trigonometry, logarithms, rounding, bitwise ops, and constants (pi, e, phi). Always returns the decimal result — for hex/bin/oct rendering, convert the returned number yourself.
expr必填