I wish I understood why immutable structures are so important, unless you are wanting a functional programming paradigm, which leaves only Haskell or Scala. Write me something in another language that I can't mutate.
IMHO if you want something immutable, don't mutate it.
"... don't mutate it": But who verifies you didn't? Your tooling should. Think about tests, formatting and linting. People could just write perfect code and not use these tools either ;)
Immutability leads to better structured code if people think about which values actually change, which not and how they depend on each other.
I think even these discussions miss a key point. I can't tell you how many times I've had, in Java, someone just throw "final" on their class because they thought nobody should extend it. I've had to copy entire classes because I couldn't use something from a library more times than I can count just for this reason.
Even "String" in java is final and immutable. I want mutable strings, for all the reasons mentioned in many of these posts -- much faster, easier to deal with, etc. Because of someone's idea that all strings should be immutable, I end out constructing tons of objects that I don't need, and compiler writers spend thousands of hours improving the optimizer to avoid these allocations, and programmers resorting to libraries with buffers and such in order to add simple strings together, all because someone thought string should be immutable.
I also don't like the habit of certain programmers to define all of their Java classes as final, but that is not immutability of object instances that the author refers to (preventing class extension vs preventing modification of objects at runtime). I think it's a valid rant but that sounds like a different topic.
Regarding mutable Strings in Java, I wonder why you had to use libraries. There are StringBuffer and StringBuilder just for that in core Java (former is present since JDK1.0), sitting alongside String (in java.lang package).
On the topic of immutability and specifically String, James Gosling gave an explanation back in 2001: artima.com/intv/gosling313.html
Performance (there are cases where immutability can provide more performance) and security basically were his two main reasons for making String immutable. I particularly like this quote:
You end up getting almost forced to replicate the object because you don't know whether or not you get to own it.
That's obvious for C, C++ or/and Rust programmers. Maybe less when we are used to work with a VM that does most of the memory allocation and ownership management.
I wish I understood why immutable structures are so important, unless you are wanting a functional programming paradigm, which leaves only Haskell or Scala. Write me something in another language that I can't mutate.
IMHO if you want something immutable, don't mutate it.
"... don't mutate it": But who verifies you didn't? Your tooling should. Think about tests, formatting and linting. People could just write perfect code and not use these tools either ;)
Immutability leads to better structured code if people think about which values actually change, which not and how they depend on each other.
From the post: softwareengineering.stackexchange....
I think even these discussions miss a key point. I can't tell you how many times I've had, in Java, someone just throw "final" on their class because they thought nobody should extend it. I've had to copy entire classes because I couldn't use something from a library more times than I can count just for this reason.
Even "String" in java is final and immutable. I want mutable strings, for all the reasons mentioned in many of these posts -- much faster, easier to deal with, etc. Because of someone's idea that all strings should be immutable, I end out constructing tons of objects that I don't need, and compiler writers spend thousands of hours improving the optimizer to avoid these allocations, and programmers resorting to libraries with buffers and such in order to add simple strings together, all because someone thought string should be immutable.
I also don't like the habit of certain programmers to define all of their Java classes as final, but that is not immutability of object instances that the author refers to (preventing class extension vs preventing modification of objects at runtime). I think it's a valid rant but that sounds like a different topic.
Regarding mutable Strings in Java, I wonder why you had to use libraries. There are StringBuffer and StringBuilder just for that in core Java (former is present since JDK1.0), sitting alongside String (in java.lang package).
On the topic of immutability and specifically String, James Gosling gave an explanation back in 2001: artima.com/intv/gosling313.html
Performance (there are cases where immutability can provide more performance) and security basically were his two main reasons for making String immutable. I particularly like this quote:
That's obvious for C, C++ or/and Rust programmers. Maybe less when we are used to work with a VM that does most of the memory allocation and ownership management.
Russ Cox has also outline why he thinks immutability is a good idea in his 2017 resolutions: research.swtch.com/go2017
(he also says he wants to a get a better understanding of generics :)