Can you only define some fields in an object constant or immutable, as in C++ class Foo { int x; cont int y; }; ?

One thing you could do is define an immutable struct in which some of the (immutable) fields are wrapped in Refs to make them mutable: julia> struct Foo x :: Ref{Int} y :: Int end julia> f = Foo(1, 2) Foo(Base.RefValue{Int64}(1), 2) julia> f.x[] += 10 # OK: mutate th…

Note that Ref is an abstract type: julia> typeof(Ref(1)) Base.RefValue{Int64} So for performance reasons you might want to use Base.RefValue instead.

The strict answer would be no, you can’t define some fields to be mutable because the concept of mutable types in Julia is different from C++. But it is possible to make it look like that. One way is already mentioned, make “mutable” fields hold a container, another is to overload setproperty! for …

I understand your question, I’m just thinking is it a mistake or anti-pattern to ever do this? So do you have a more concrete example/reason to do this? If it’s just out of curiosity, and possibly unfamiliarity with Julia (it’s not clear for how long you’ve used Julia), then FYI: structs are immuta…

Partially mutable object

New to Julia

lmiq October 28, 2021, 6:52pm 5

Here is a discussion of many alternatives: Mutable scalar in immutable object: the best alternative?

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Partially mutable object

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