Over 10 years ago, I had this sort of a prediction that, with the massive adoption of a dynamic language like javascript on both client/server sides and test-driven development gaining a lot of ground, the future of programming would be dynamic and “feedback-driven”. As in, you would immediately see the results of your code as you type, based on the tests you created. To naively simplify, imagine a split screen of your code editor and a console view showing relevant watch expressions from the code you’re typing.
Instead what happened was the industry’s focus shifted to type safety and smart compilers, and I followed along. I’m just not smart enough to question where the whole industry was heading. And my speck of imagination on how coding would have looked like in the future wasn’t completely thought out. It was just that, a speck of imagination that occurred to me as I was debugging something tedious.
Now, most of the programming language world, seem to be focusing on smarter compilers. But is there some language or platform, that focus instead on a different kind of programming paradigm (not sort of OOP, FP paradigm, may be call it the programming workflow paradigm?). May be it comes with a really strong debugger tooling that’s constantly giving you feedback on what your code is actually doing. Think REPL on steroids. I can imagine there would be challenges with parsing/evaluating incomplete code syntax and functions. So I guess, the whole compiler/translator side has to be thought out from the ground up as well.
Disclaimer: There’s a good chance I simply don’t know what I’m talking about because I’m no language designer or even close to understanding how programming languages and it’s ecosystems are created. Just sharing some thoughts I had as a junior dev back in the day.
The main issue I have with this is the exclusive focus on happy path. The point of unit tests and especially mutation testing is to validate that every code path has a defined test and hence defined behavior. I wouldn’t want to give that up, myself. I’m a huge believer in type safety and immutable objects and other things that prevent architectural misuse.
Just to share a perspective from erlang/elixir: pattern matching to filter for only happy-path inputs and the principle of “letting it fail” (when the inputs don’t match the expected shape) works really well in some paradigms (in this case, the actor model + OTP, erlang’s 9 9s of uptime, etc). In that kind of architecture you can really only care about the happy path, because the rest is malformed and can be thrown away without issue.
I’d imagine there would be no need to give up type safety, unit testing and all that though. I’m thinking more about language and tool creators’ focus and efforts going mostly into compiler and type safety.
I’ve seen live updates for things like Go, NodeJS, Vue, Flutter, Angular, and you can recompile a Java class during debugging in Java (with limitations as certain things like static variables and methods need a full restart). More support and integration is certainly better but it doesn’t feel like it’s in a bad place to me.
This is what Smalltalk is all about, and it has been like that since it’s origin: you basically program in the debugger, you program running, you change something, you proceed the debugger, etc. That’s why technics like TDD, refactoring, and others were developed in Smalltalk and just later translated to other languages (and always lacking, since no one reproduces the live programming experience 100%). As the time passed, attention has moved to other languages and most people not ignores what it was to program like that. But there are still some implementations around: I work with Pharo (https://pharo.org), and I can to say is all what you ask for in this post :)
Compose and flutter both have “realtime” previews? And I believe react has something similar? They aren’t truely realtime, because usually there is a compile/execute step happening, but they can be fairly good for rapid feedback?
https://docs.flutter.dev/tools/hot-reload
https://blaszcz.uk/live-reload-with-compose-web/
For unit tests, there is https://infinitest.github.io/, which automatically updates your tests as you code. Never used it though.
