# How to simplify the code in constructing struct
**URL:** https://discourse.julialang.org/t/how-to-simplify-the-code-in-constructing-struct/70411
**Category:** New to Julia
**Tags:** inheritance, struct
**Created:** [October 26, 2021, 3:07pm UTC](https://discourse.julialang.org/t/how-to-simplify-the-code-in-constructing-struct/70411 "2021-10-26T15:07:39Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@zhangjin](https://discourse.julialang.org/u/zhangjin)
#### Post date: [October 26, 2021, 3:07pm UTC](https://discourse.julialang.org/t/how-to-simplify-the-code-in-constructing-struct/70411/1 "2021-10-26T15:07:39Z")
I know the julia don’t have the “class”, but I need it. So I try to use struct to complete it. I try to implement the initialization of inheritance like following code.
```julia
struct P1
M::Int8
Ks::Int8
metric::String
end
struct P2
D::Int16
Ds::Int16
k_v::Int64
function P2(D,k_v)
Ds = D*k_v
new(D, Ds, k_v)
end
end
struct C
M::Int8
Ks::Int8
metric::String
D::Int16
Ds::Int16
k_v::Int64
function C(M, Ks, metric, D, k_v)
p1 = P1(M, Ks, metric)
M, Ks, metric = p1.M, p1.Ks, p1.metric
p2 = P2(D, k_v)
D, Ds, k_v = p2.D, p2.Ds, p2.k_v
new(M, Ks, metric, D, Ds, k_v)
end
end
```
But I notice when the field of struct change, it is troublesome to adjust the code. I want to know the more reasonable ways to implement it.
Thanks in advance for any help/suggestion.
---
### Author:  [@Oscar\_Smith](https://discourse.julialang.org/u/Oscar_Smith)
#### Post date: [October 26, 2021, 3:12pm UTC](https://discourse.julialang.org/t/how-to-simplify-the-code-in-constructing-struct/70411/2 "2021-10-26T15:12:03Z")
Why not just
```julia
struct C
p1 :: P1
p2 :: P2
function C(M, Ks, metric, D, k_v)
p1 = P1(M, Ks, metric)
p2 = P2(D, k_v)
new(p1, p2)
end
end
```
---
### Author:  [@zhangjin](https://discourse.julialang.org/u/zhangjin)
#### Post date: [October 26, 2021, 3:17pm UTC](https://discourse.julialang.org/t/how-to-simplify-the-code-in-constructing-struct/70411/3 "2021-10-26T15:17:24Z")
@Oscar_Smith It is ok. If I can access the field without the name of “parents”, I think it is better.
---
### Author:  [@stillyslalom](https://discourse.julialang.org/u/stillyslalom)
#### Post date: [October 26, 2021, 3:34pm UTC](https://discourse.julialang.org/t/how-to-simplify-the-code-in-constructing-struct/70411/4 "2021-10-26T15:34:32Z")
See [this](https://discourse.julialang.org/t/generate-a-mutable-struct-which-inherits-others/47347/5) thread for related discussion. If you’re worried about the visual noise that results from accessing deeply nested fields, you may appreciate [UnPack.jl](https://github.com/mauro3/UnPack.jl).
---
### Author:  [@zhangjin](https://discourse.julialang.org/u/zhangjin)
#### Post date: [October 26, 2021, 3:46pm UTC](https://discourse.julialang.org/t/how-to-simplify-the-code-in-constructing-struct/70411/5 "2021-10-26T15:46:17Z")
@stillyslalom Thanks for your answer, It is very useful.
---
### Author:  [@singularitti](https://discourse.julialang.org/u/singularitti)
#### Post date: [October 31, 2021, 3:46am UTC](https://discourse.julialang.org/t/how-to-simplify-the-code-in-constructing-struct/70411/6 "2021-10-31T03:46:09Z")
You might want to have a look at these packages:
- [YingboMa/Unityper.jl (github.com)](https://github.com/YingboMa/Unityper.jl)
- [rjplevin/Classes.jl: A simple, Julian approach to inheritance of structure and methods (github.com)](https://github.com/rjplevin/Classes.jl)
- [gcalderone/ReusePatterns.jl: Implement composition and concrete subtyping in Julia. (github.com)](https://github.com/gcalderone/ReusePatterns.jl)
- [ANN: StructuralInheritance.jl - Community - JuliaLang](https://discourse.julialang.org/t/ann-structuralinheritance-jl/16515)
- [rafaqz/Mixers.jl: Julia mixin macros. Mixed, not stirred (github.com)](https://github.com/rafaqz/Mixers.jl)
- [JeffreySarnoff/TypedDelegation.jl: Easily apply functions onto fields’ values. Use a struct’s fields as operands for operations on values of that type. (github.com)](https://github.com/JeffreySarnoff/TypedDelegation.jl)