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>Js has const, C has const, Java final. C# has readonly and const >Imho it'd be awesome if mutability were not the default If they decided one day that - "le

>Js has const, C has const, Java final. C# has readonly and const >Imho it'd be awesome if mutability were not the default If they decided one day that - "let's make immutable by default", then it'd be performance hit - wouldn't it?

awild 4y ago
> If they decided one day that - "let's make immutable by default", then it'd be performance hit - wouldn't it? Not really. It's just a syntactic default, reassigning local variables should be discouraged from except for iterators etc. It just fosters bad habits. For example, A list can still be mutated like usual, the reference however may not change. This usually allows compilers to do optimizations in multithreaded situations. But that's not why I code that way, it reduces the cognitive burden of keeping track which variables are actual moving parts as opposed to context/names etc. > C# has readonly and const Haven't written C# in a few years, GP was talking about variables as far as I can tell and their lack of immutability.
kroltan 4y ago
C# does not (as far as I know) have readonly or const for local variables, only to fields. You can even have consts inside method bodies, but they are only actual compile-time constants. codeflo means to declare a local variable that cannot be reassigned later. void Foo() { // this is possible in C# today, but only for compile-time constants const int Bar = 42; // this is what codeflo wants: variables that cannot be changed after declaration, but can hold runtime values readonly string text = $"Blah: {Bar + System.Environment.ProcessorCount}"; // with such a variable, you wouldn't be able to reassign it later: text = "Some other text"; // the line above would be a compile-time error, just like trying to reassign to a readonly field. }

awild 4y ago

> If they decided one day that - "let's make immutable by default", then it'd be performance hit - wouldn't it? Not really. It's just a syntactic default, reassigning local variables should be discouraged from except for iterators etc. It just fosters bad habits. For example, A list can still be mutated like usual, the reference however may not change. This usually allows compilers to do optimizations in multithreaded situations. But that's not why I code that way, it reduces the cognitive burden of keeping track which variables are actual moving parts as opposed to context/names etc. > C# has readonly and const Haven't written C# in a few years, GP was talking about variables as far as I can tell and their lack of immutability.

kroltan 4y ago

C# does not (as far as I know) have readonly or const for local variables, only to fields. You can even have consts inside method bodies, but they are only actual compile-time constants. codeflo means to declare a local variable that cannot be reassigned later. void Foo() { // this is possible in C# today, but only for compile-time constants const int Bar = 42; // this is what codeflo wants: variables that cannot be changed after declaration, but can hold runtime values readonly string text = $"Blah: {Bar + System.Environment.ProcessorCount}"; // with such a variable, you wouldn't be able to reassign it later: text = "Some other text"; // the line above would be a compile-time error, just like trying to reassign to a readonly field. }