'use strict';

const binOps = '+ - / % & | ^ << >> > >= < <= == != && ||'

.split(/\s+/)

.reduce((res, e) => {

res[e] = e;

return res;

}, {

'u*': '*'

});

const signedBinOps = {

'*': '*'

};

const unOps = {

'!': '!',

'~': '~'

};

const rpn = (seq, arr) => {

if (typeof seq === 'string') {

seq = seq.split(/\s+/);

}

// if (typeof arr === 'string') {

// arr = arr.split(/\s+/);

// }

arr = arr.map(e => e.name);

for (let j = 0; j < 100; j++) {

for (let i = 0; i < seq.length; i++) {

const cmd = seq[i];

if (unOps[cmd]) {

arr.push(cmd + arr.pop());

} else

if (signedBinOps[cmd]) {

const rhs = arr.pop();

const lhs = arr.pop();

arr.push(`($signed(${lhs}) ${signedBinOps[cmd]} $signed(${rhs}))`);

} else

if (binOps[cmd]) {

const rhs = arr.pop();

const lhs = arr.pop();

arr.push(`(${lhs} ${binOps[cmd]} ${rhs})`);

} else

if (cmd.slice(0, -1) === '(' && binOps[cmd.slice(1)]) {

const lhs = arr.shift();

const rhs = arr.shift();

arr.unshift(`(${lhs} ${cmd.slice(1)} ${rhs})`);

} else

if (cmd === 'swap') {

const rhs = arr.pop();

const lhs = arr.pop();

arr.push(rhs);

arr.push(lhs);

} else {

const num = Number(cmd);

if (!isNaN(num)) {

arr.push(num);

}

}

if (arr.length < 2) {

return arr[0];

}

}

}

return arr[0];

};

module.exports = rpn;