swizard task in Node

main.js

var parse = require('sexpr-plus').parse
var Q = require('q')

var ops = {
        '+' : (a, b) => a + b
,       '-' : (a, b) => a - b
,       '*' : (a, b) => a * b
}

function eval(p)
{
        switch (p.type)
        {
        case 'list':
                var op = ops[p.content[0].content]
                var args = p.content.slice(1)
                return op.apply(null, args.map(eval))
        case 'atom':
                return parseInt(p.content)
        }
}

var foo = '(* (+ 1 2) (+ 3 4))'
console.log(eval(parse(foo)[0]))

var opsA = {
        '+' : (a, b) => Q.delay(2000).then(() => a + b)
,       '-' : (a, b) => Q.delay(3000).then(() => a - b)
,       '*' : (a, b) => Q.delay(10000).then(() => a * b)
}


function evalA(p)
{
        switch (p.type)
        {
        case 'list':
                var op = opsA[p.content[0].content]
                var args = p.content.slice(1)
                console.log(p.content[0].content)
                return Q
                        .all(args.map(evalA))
                        .then((args) => op.apply(null, args))
        case 'atom':
                return parseInt(p.content)
        }
}

evalA(parse(foo)[0]).then(console.log)

var queue = require("promise-task-queue")()

queue.define
        ( "heavy"
        , (o) => o.op.apply(null, o.args)
        , { concurrency: 1 }
        )

function evalQ(p)
{
        switch (p.type)
        {
        case 'list':
                var op = opsA[p.content[0].content]
                var args = p.content.slice(1)
                return Q
                        .all(args.map(evalQ))
                        .then((args) =>queue.push("heavy", {op : op, args :args}))
        case 'atom':
                return parseInt(p.content)
        }
}

var s = Date.now()
evalQ(parse(foo)[0]).then((x) => console.log("Q", x, Date.now() - s, "ms"))