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August 12, 2014 09:02
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// | |
// Promise.swift | |
// Promise | |
// | |
// Created by Benjamin Gruenbaum on 8/12/14. | |
// Copyright (c) 2014 Tipranks. All rights reserved. | |
// | |
import Foundation | |
struct Pair<A,B>{ | |
var left:A? | |
var right:B? | |
} | |
public class Promise<T,E>{ | |
var state:PromiseState<T,E> = PromiseState(state: .Pending, value: nil, error: nil) | |
var fHandlers:[(T) -> ()] = [] | |
var rHandlers:[(E) -> ()] = [] | |
func then<NT,NE>(onFulfilled:(T) -> Promise<NT,NE>) -> Promise<NT,NE>{ | |
var p = Promise<NT,NE>() | |
fHandlers.append({ (t:T) in | |
let res = onFulfilled(t) | |
res.then({ p.fulfill($0) }) | |
res.catch({ p.reject($0) }) | |
}) | |
return p | |
} | |
func then<NT>(onFulfilled:(T) -> NT) -> Promise<NT,E> { | |
var p = Promise<NT,E>() | |
fHandlers.append({ (t:T) in | |
let res = onFulfilled(t) | |
p.fulfill(res) | |
}) | |
return p | |
} | |
func catch<NT,NE>(onRejected: (E) -> Promise<NT,NE>) -> Promise<NT,NE>{ | |
var p = Promise<NT,NE>() | |
rHandlers.append({ (t:E) in | |
let res = onRejected(t) | |
res.then({ p.fulfill($0) }) | |
res.catch({ p.reject($0) }) | |
}) | |
return p; | |
} | |
func catch<NT>(onRejected: (E) -> NT) -> Promise<NT,E> { | |
var p = Promise<NT,E>() | |
rHandlers.append({ (t:E) in | |
let res = onRejected(t) | |
p.fulfill(res) | |
}) | |
return p | |
} | |
private func fulfill(val:T) { | |
if state.state != .Pending { | |
return | |
} | |
self.state.state = .Fulfilled | |
self.state.value = val | |
} | |
private func reject(err:E) { | |
if state.state != .Pending { | |
return | |
} | |
assert(self.state.state != .Rejected) | |
self.state.state = .Rejected | |
self.state.error = err | |
} | |
} | |
protocol Thenable<T> { | |
func then<NT,NE>(onFulfilled:(T) -> Promise<NT,NE>) -> Promise<NT,NE> | |
} | |
struct PromiseState<T,E> { | |
var state:State | |
var value:T? | |
var error:E? | |
} | |
// hack for - unimplemented IR generation feature non-fixed multi-payload enum layout | |
enum State { | |
case Pending | |
case Fulfilled | |
case Rejected | |
} |
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