Apple to let developers port iOS apps to Mac, starts with own apps in macOS Mojave
Concluding its WWDC 2018 keynote, Apple offered a "sneak peek" at what it called a multi-year project to bring iOS apps to the Mac.

While iOS and macOS share similar underlying frameworks, there are also key differences that have made porting iOS apps to Mac difficult, said Apple's senior VP of Software Engineering Craig Federighi. The company is incorporating previously iOS-only frameworks into macOS, and allowing those apps to tap into things like mouse and trackpad input, resizable windows, scroll bars, and copy-and-paste.
Some apps in this fall's macOS Mojave -- namely Home, News, Voice Memos, and Apple Books -- are in fact ports of their iOS equivalents.
Federighi denied speculation that Apple will eventually merge macOS and iOS, bringing up a dramatic "No" slide when raising the topic.

Rumors of iOS apps coming to the Mac have been around since 2017. Apple could partly be hoping to reinvigorate the Mac App Store, which has languished given the ability of Mac developers to sell apps anywhere they want without giving Apple a percentage of revenues or going through screening.

While iOS and macOS share similar underlying frameworks, there are also key differences that have made porting iOS apps to Mac difficult, said Apple's senior VP of Software Engineering Craig Federighi. The company is incorporating previously iOS-only frameworks into macOS, and allowing those apps to tap into things like mouse and trackpad input, resizable windows, scroll bars, and copy-and-paste.
Some apps in this fall's macOS Mojave -- namely Home, News, Voice Memos, and Apple Books -- are in fact ports of their iOS equivalents.
Federighi denied speculation that Apple will eventually merge macOS and iOS, bringing up a dramatic "No" slide when raising the topic.

Rumors of iOS apps coming to the Mac have been around since 2017. Apple could partly be hoping to reinvigorate the Mac App Store, which has languished given the ability of Mac developers to sell apps anywhere they want without giving Apple a percentage of revenues or going through screening.
Comments
Craig: "No. Of course not!"
...it was a good moment of comic relief.
This announcement (the Marzipan rumor) is a good approach to lowering the barrier of entry to building native-Mac apps. As Gruber and other devs predicted, it's not "iOS apps running on Mac!" but is the addition of a framework (UIKit) to macOS to make it easier to build a native-Mac app based on work already done for an iOS app. Exactly what we devs said in the comments here. It won't be an iOS app on Mac (other than that you wrote code for iOS first)...the Mac version won't look like a windowed iOS app and will instead look, operate, and be like a Mac app.
This should increase the number of useful native Mac apps, which is their goal. If they instead allowed iOS apps to run in a window it would only reduce the number of native Mac apps even further. RIM experienced that pain when they announced their platform would run both Blackberry and Android apps. Guess what happened? Devs stopped making Blackberry apps, because why bother if it could run Android apps? I wouldn't expect Apple to make that same mistake on the Mac.
I doubt this will be the case.
Adding UIKit made the most sense when I was trying to port a barcode tutorial app that I macOS and I couldn’t work out how to do it despite developing it in iOS being super simple. I wished Apple just ported UIKit to macOS and have it work the way a macOS app would.
I think Apple is able to read my mind. I mean given iPhone and Apple Watch are connected to me constantly it seems maybe they’ve worked out how to read brain waves as well. That’s both super cool and super scary as well
What do you think the next step would be, separating them? Don't think so.
I'm a complete noob to Xcode but I don't agree with you at all. What's so difficult to learn with Xcode? I suspect you're thinking about Swift but then you're writing for a completely new programming language and one that makes far more sense than C++, C# etc.
Apple doesn't do low hanging fruit. It never has and never will. Get over it.
I DO want to run iOS apps on my MacBook because there are apps I use on iOS that don't exist on macOS and this just seems to be a happy in-between.
If you want a Mac to do all the cool things an iPad can do then get a sodding iPad that CAN do all the cool things a iPad can do because... well it's an iPad already. It's not rocket science.
The reason I want iOS apps running on my macBook is simply because I need a macBook but I also have an iPad 3 that can only go to iOS 9. One app I use all the time will run on iOS 9 but it has issues with the share panel which is the way it does things to share the data files with iOS, Windows, and Android. There is no macOS version and using the app on iPhone can be tricky in order to get the most out of it. But if this app was useable on macOS then I can do that side of thing on the Mac then upload the datafile to the iPhone and use it in a reader capacity which works well.
Just because the use case doesn't exist for you doesn't mean that it's a rubbish idea.
Meanwhile, iOS is a very successful platform of native applications.
This is wrong. The iOS app is not running “inside” of a Mac app. macOS is gaining the UIKit framework, and will implement it differently than iOS does. The code becomes more cross-platform.
If if you’re not a developer, you probably will struggle with this. Sorry.
Dark Mode reminds me of Copland's P Theme. And QuickLook just continues to look more like OpenDoc Editors.
There's nothing new.
🤦🏾♂️
Christ on a bicycle …
Why can't there exist a mac tablet, that has a touch screen with Apple Pencil support?
Simply insisting that what I am asking for isn't needed is such a Window/PC thing to do.
I have a MacBook Pro today and literally ZERO desire to buy another one - I don't care how fast it might be. I know what the MacBook Pro ownership experience is all about and quite frankly ... I'm bored with it. I see the iPad Pro with new features (Rear Facing Camera, Apple Pencil, Tablet Form Factor) but a software ecosystem that falls well short of what I need. Merely putting the "Pro" moniker on a product doesn't make it a "Product for Professionals." And I certainly do not want to carry two devices.
Apple's insistence that iOS be the only platform for it's tablets is holding back both the iPad and the Mac. This is a recipe for failure.
I suspect that “fooling arond a bit” isn’t really the basis of an informed opinion.
NEXT!
What Apple is doing is not getting iOS apps running on a Mac they’re setting it up so that developers don’t have to think multiple ways for doing the development of the UI. Basically the developer only has to use UIKit syntax and Xcode will translate it to NS methods. This will cut development times considerably. You’d still be making a macOS app you just won’t need to use macOS syntaxes.