与前端训练营的日子 --Week03

var regexp = /([0-9\.]+)|([ \t]+)|([\r\n]+)|(\*)|(\/)|(\+)|(\-)/g;
var dictionary = ["Number", "Whitespace", "LineTerminator", "*", "/", "+", "-"];

function MultiplicativeExpression(source) {
        if(source[0].type === "Number") {
            let node = {
                type:"MultiplicativeExpression",
                children:[source[0]]
            }
            source[0] = node;
            return MultiplicativeExpression(source);
        }
        if (source[0].type === "MultiplicativeExpression" && source[1] && source[1].type === "*") {
            let node = {
                type:"MultiplicativeExpression",
                operator:"*",
                children:[]
            }
            node.children.push(source.shift());
            node.children.push(source.shift());
            node.children.push(source.shift());
            source.unshift(node);
            return MultiplicativeExpression(source);
        }
        if (source[0].type === "MultiplicativeExpression" && source[1] && source[1].type === "/") {
            let node = {
                type:"MultiplicativeExpression",
                operator:"/",
                children:[]
            }
            node.children.push(source.shift());
            node.children.push(source.shift());
            node.children.push(source.shift());
            source.unshift(node);
            return MultiplicativeExpression(source);
        }
        if(source[0].type === "MultiplicativeExpression"){
            return source[0];
        }
        return MultiplicativeExpression(source);
    }