JS中缀表达式转前缀表达式
var operators = {'=>': 4, '=': 3, '+': 2, '-': 2, '*': 1, '/': 1, '%': 1, '(': 1, ')': 1}; Interpreter.prototype.toPrefix = function (tokens) { var result = [], stack = []; while (tokens.length) { var next = tokens.pop(); if (!operators[next]) { result.push(next); } else if (next === ')') { stack...