Define your terms before relying on platitudes. Mutability isn’t cleaner if we want composition, particularly in the face of concurrency. Being idiomatic isn’t good or bad, but patterned; not all patterns are universally desirable. The only one which stands up to scrutiny is efficiency, which leads to the cult of performance-at-all-costs if one is not thoughtful.
I agree somewhat, but I’d also say any codebase needs some level of “dogmatic” standard (ideally enforced via tooling). Otherwise you still end up with bad, messy code (I’d even say messier, as you don’t even get consistency)
I’d agree with the first half, but not the second. Sometimes mutability allows for more concise code, although in most cases it’s better to not mutate at all
The app working isn’t good enough, it needs to be maintainable. From a professional perspective, unmaintainable code is useless code.
Code that mutates everywhere is generally harder to reason about and therefore harder to maintain, so just don’t do it (unless there’s literally no other practical way, but genuinely these are very rare cases)
Fair play, I guess we’re probably just gonna disagree.
In my experience I’d say mutable code (larger than anything other than toy examples) always results in more time spent fixing bugs down the line, predominantly because it’s objectively harder for humans to reason about multiple one to many relationships rather than multiple one to one relationships. I’d say because you need to think about all possible states of the set of mutable variables in your code in order to completely understand it (and I don’t just mean understanding the intended purpose of the code, I mean understanding everything that code is capable of doing), that usually results in a more convoluted implementation than the pretty linear way you typically read functional code.
Longer code is practically always better if it’s easier to understand than the shorter alternative. Software engineers aren’t employed to play code golf, they’re employed to write maintainable software. Though I’ll say ultra high performance applications might be the exception here—but 99% of engineers aren’t doing anything like that.
I’m always happy to be convinced otherwise, but I’ve never seen a convincing argument
Random example, imagine a variable that holds the time of the last time the user moved the mouse. Or in a game holding the current selected target of the player. Or the players gold amount. Or its level. Or health. Or current position.
Keeping state managed. The data for the function will be very predictable. This is especially important when it comes to multithreading. You can’t have a race condition where two things update the same data when they never update it that way at all.
Rather than me coming up with an elaborate and contrived example, I suggest giving a language like Elixir a try. It tends to force you into thinking in terms of immutability. Bit of a learning curve if you’re not used to it, but it just takes practice.
Const everything by default
If you need to mutate it, you don’t, you need to refactor.
Dogmatic statements like this lead to bad, messy code. I’m a firm believer that you should use whatever style fits the problem most.
Although I agree most code would be better if people followed this dogma, sometimes mutability is just more clean/idiomatic/efficient/…
Define your terms before relying on platitudes. Mutability isn’t cleaner if we want composition, particularly in the face of concurrency. Being idiomatic isn’t good or bad, but patterned; not all patterns are universally desirable. The only one which stands up to scrutiny is efficiency, which leads to the cult of performance-at-all-costs if one is not thoughtful.
I agree somewhat, but I’d also say any codebase needs some level of “dogmatic” standard (ideally enforced via tooling). Otherwise you still end up with bad, messy code (I’d even say messier, as you don’t even get consistency)
What about movable objects? You can’t move a const object
A const object meets an immutable variable
I’d agree with the first half, but not the second. Sometimes mutability allows for more concise code, although in most cases it’s better to not mutate at all
I feel like I should maybe have put a “probably” in there
After all “there’s no silver bullet”, but in anything but a few edge cases, the rule applies, IMO
Sorry, I want to make an app that works, not a perfect art piece.
The app working isn’t good enough, it needs to be maintainable. From a professional perspective, unmaintainable code is useless code.
Code that mutates everywhere is generally harder to reason about and therefore harder to maintain, so just don’t do it (unless there’s literally no other practical way, but genuinely these are very rare cases)
I personally disagree, forcing yourself to use non mutable variables only leads to longer and more convoluted code.
Fair play, I guess we’re probably just gonna disagree.
In my experience I’d say mutable code (larger than anything other than toy examples) always results in more time spent fixing bugs down the line, predominantly because it’s objectively harder for humans to reason about multiple one to many relationships rather than multiple one to one relationships. I’d say because you need to think about all possible states of the set of mutable variables in your code in order to completely understand it (and I don’t just mean understanding the intended purpose of the code, I mean understanding everything that code is capable of doing), that usually results in a more convoluted implementation than the pretty linear way you typically read functional code.
Longer code is practically always better if it’s easier to understand than the shorter alternative. Software engineers aren’t employed to play code golf, they’re employed to write maintainable software. Though I’ll say ultra high performance applications might be the exception here—but 99% of engineers aren’t doing anything like that.
I’m always happy to be convinced otherwise, but I’ve never seen a convincing argument
Scalauser unite! There are dozens of us, dozens!Scala? Can we reimplement it in Rust?
sure, just make sure to add “blazingly fast” in the description and append “-rs” to the name
But does it do everything in anonymous functions and lambdas?
It can
That is a… strange take.
Random example, imagine a variable that holds the time of the last time the user moved the mouse. Or in a game holding the current selected target of the player. Or the players gold amount. Or its level. Or health. Or current position.
In all those cases, the answer is to swap in a new variable and throw the old one away.
Legit question because i think I’m misunderstanding. But if its a const, how are you able to swap or replace it?
It’s only a const within a function. You can pass the value to another function and changing it as it’s passed. For example:
In functional programming, you tend to keep track of state on the stack like this.
What is the advantage of this VS just overwriting the var?
Keeping state managed. The data for the function will be very predictable. This is especially important when it comes to multithreading. You can’t have a race condition where two things update the same data when they never update it that way at all.
Hm I’m having trouble visualizing this do you know a quick little example to illustrate this?
Rather than me coming up with an elaborate and contrived example, I suggest giving a language like Elixir a try. It tends to force you into thinking in terms of immutability. Bit of a learning curve if you’re not used to it, but it just takes practice.