NamedTuple Constructor Support for FieldArray Subtypes

[cadojo]

I have found NamedTuple to be a performant way to initialize FieldArray subtypes. See, for example, the following code in AstrodynamicalModels.jl. I think it may also be useful sometimes to go in reverse: convert a FieldArray subtype back into a NamedTuple. Do you agree this may be useful, and without undesirable side effects? If so, should this PR include a Base.convert method too?

I got this idea from SciML's Base.NamedTuple method for LabelledArrays.jl.

Thanks for reading!

"""
A mutable vector, with labels, for 6DOF Cartesian states.
"""
Base.@kwdef mutable struct CartesianState{F} <: FieldVector{6,F}
    x::F = 0.0
    y::F = 0.0
    z::F = 0.0
    ẋ::F = 0.0
    ẏ::F = 0.0
    ż::F = 0.0

    CartesianState{F}(::UndefInitializer) where {F} = new{F}()
    CartesianState(::UndefInitializer) = CartesianState{Float64}(undef)

    CartesianState{F}(x, y, z, ẋ, ẏ, ż) where {F} = new{F}(x, y, z, ẋ, ẏ, ż)
    CartesianState(x, y, z, ẋ, ẏ, ż) = new{promote_type(typeof(x), typeof(y), typeof(z), typeof(ẋ), typeof(ẏ), typeof(ż))}(x, y, z, ẋ, ẏ, ż)
    CartesianState{F}(state::NamedTuple) where {F} =
        let
            (; x, y, z, ẋ, ẏ, ż) = merge((; x=zero(F), y=zero(F), z=zero(F), ẋ=zero(F), ẏ=zero(F), ż=zero(F)), state)
            CartesianState{F}(x, y, z, ẋ, ẏ, ż)
        end
    CartesianState(state::NamedTuple) = CartesianState{Float64}(state)
end

[codecov]

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[mateuszbaran]

Sounds reasonable to me, also for convert. Could you also add a test?

[mateuszbaran]

I'd also prefer to avoid unrelated formatting changes in this PR.

[cadojo]

I'd also prefer to avoid unrelated formatting changes in this PR.

Yup, forgot to remove my editor's format-on-save option. I've reverted the formatting changes.

Could you also add a test?

I have added tests, but they fail due to missing Base methods for FieldArray types. I guess those must be supplied by StaticArrays? Does this PR belong in StaticArrays instead?

Test Failure Output

(StaticArraysCore) pkg> test
     Testing StaticArraysCore
      Status `/private/var/folders/vc/rjqggbq92mj_strb625fy2g40000gn/T/jl_FO9yCN/Project.toml`
  [1e83bf80] StaticArraysCore v1.4.2 `~/StaticArraysCore.jl`
  [8dfed614] Test
      Status `/private/var/folders/vc/rjqggbq92mj_strb625fy2g40000gn/T/jl_FO9yCN/Manifest.toml`
  [1e83bf80] StaticArraysCore v1.4.2 `~/StaticArraysCore.jl`
  [2a0f44e3] Base64
  [b77e0a4c] InteractiveUtils
  [56ddb016] Logging
  [d6f4376e] Markdown
  [9a3f8284] Random
  [ea8e919c] SHA v0.7.0
  [9e88b42a] Serialization
  [8dfed614] Test
Precompiling project...
  1 dependency successfully precompiled in 1 seconds. 1 already precompiled.
     Testing Running tests...
types: Error During Test at /Users/joey/StaticArraysCore.jl/test/runtests.jl:34
  Test threw exception
  Expression: __FieldArrayTest(1, 2, 3) isa SizedArray
  MethodError: no method matching size(::__FieldArrayTest)
  
  Closest candidates are:
    size(::AbstractArray{T, N}, ::Any) where {T, N}
     @ Base abstractarray.jl:42
    size(::Core.Compiler.StmtRange)
     @ Base show.jl:2774
    size(::BitVector)
     @ Base bitarray.jl:104
    ...
  
  Stacktrace:
    [1] length
      @ ./abstractarray.jl:315 [inlined]
    [2] isempty(a::__FieldArrayTest)
      @ Base ./abstractarray.jl:1220
    [3] typeinfo_prefix(io::IOContext{IOBuffer}, X::__FieldArrayTest)
      @ Base ./arrayshow.jl:585
    [4] show_vector(io::IOContext{IOBuffer}, v::__FieldArrayTest, opn::Char, cls::Char)
      @ Base ./arrayshow.jl:515
    [5] show(io::IOContext{IOBuffer}, X::__FieldArrayTest)
      @ Base ./arrayshow.jl:486
    [6] show_unquoted(io::IOContext{IOBuffer}, ex::__FieldArrayTest, ::Int64, ::Int64)
      @ Base ./show.jl:1443
    [7] show_unquoted(io::IOContext{IOBuffer}, ex::__FieldArrayTest, indent::Int64, prec::Int64, ::Int64)
      @ Base ./show.jl:1444
    [8] show_list(io::IOContext{IOBuffer}, items::Vector{Any}, sep::String, indent::Int64, prec::Int64, quote_level::Int64, enclose_operators::Bool, kw::Bool)
      @ Base ./show.jl:1688
    [9] show_list
      @ ./show.jl:1669 [inlined]
   [10] show_unquoted(io::IOContext{IOBuffer}, ex::Expr, indent::Int64, prec::Int64, quote_level::Int64)
      @ Base ./show.jl:2135
   [11] show_unquoted
      @ ./show.jl:1924 [inlined]
   [12] print(io::IOContext{IOBuffer}, ex::Expr)
      @ Base ./show.jl:1439
   [13] sprint(f::Function, args::Expr; context::Pair{Symbol, Bool}, sizehint::Int64)
      @ Base ./strings/io.jl:112
   [14] sprint
      @ ./strings/io.jl:107 [inlined]
   [15] eval_test(evaluated::Expr, quoted::Expr, source::LineNumberNode, negate::Bool)
      @ Test ~/.julia/juliaup/julia-1.10.1+0.aarch64.apple.darwin14/share/julia/stdlib/v1.10/Test/src/Test.jl:390
   [16] macro expansion
      @ ~/.julia/juliaup/julia-1.10.1+0.aarch64.apple.darwin14/share/julia/stdlib/v1.10/Test/src/Test.jl:669 [inlined]
   [17] macro expansion
      @ ~/StaticArraysCore.jl/test/runtests.jl:34 [inlined]
   [18] macro expansion
      @ ~/.julia/juliaup/julia-1.10.1+0.aarch64.apple.darwin14/share/julia/stdlib/v1.10/Test/src/Test.jl:1577 [inlined]
   [19] top-level scope
      @ ~/StaticArraysCore.jl/test/runtests.jl:4
types: Error During Test at /Users/joey/StaticArraysCore.jl/test/runtests.jl:35
  Test threw exception
  Expression: convert(NamedTuple, __FieldArrayTest(1, 2, 3)) isa NamedTuple
  MethodError: no method matching size(::__FieldArrayTest)
  
  Closest candidates are:
    size(::AbstractArray{T, N}, ::Any) where {T, N}
     @ Base abstractarray.jl:42
    size(::Core.Compiler.StmtRange)
     @ Base show.jl:2774
    size(::BitVector)
     @ Base bitarray.jl:104
    ...
  
  Stacktrace:
    [1] axes
      @ ./abstractarray.jl:98 [inlined]
    [2] collect(A::__FieldArrayTest)
      @ Base ./array.jl:761
    [3] _totuple(::Type{Tuple}, ::__FieldArrayTest)
      @ Base ./tuple.jl:425
    [4] Tuple(itr::__FieldArrayTest)
      @ Base ./tuple.jl:391
    [5] (NamedTuple{(:a, :b, :c)})(itr::__FieldArrayTest)
      @ Base ./namedtuple.jl:149
    [6] NamedTuple(array::__FieldArrayTest)
      @ StaticArraysCore ~/StaticArraysCore.jl/src/StaticArraysCore.jl:323
    [7] convert(::Type{NamedTuple}, array::__FieldArrayTest)
      @ StaticArraysCore ~/StaticArraysCore.jl/src/StaticArraysCore.jl:322
    [8] macro expansion
      @ ~/.julia/juliaup/julia-1.10.1+0.aarch64.apple.darwin14/share/julia/stdlib/v1.10/Test/src/Test.jl:669 [inlined]
    [9] macro expansion
      @ ~/StaticArraysCore.jl/test/runtests.jl:35 [inlined]
   [10] macro expansion
      @ ~/.julia/juliaup/julia-1.10.1+0.aarch64.apple.darwin14/share/julia/stdlib/v1.10/Test/src/Test.jl:1577 [inlined]
   [11] top-level scope
      @ ~/StaticArraysCore.jl/test/runtests.jl:4
Test Summary: | Pass  Error  Total  Time
types         |   19      2     21  1.0s
ERROR: LoadError: Some tests did not pass: 19 passed, 0 failed, 2 errored, 0 broken.
in expression starting at /Users/joey/StaticArraysCore.jl/test/runtests.jl:3
ERROR: Package StaticArraysCore errored during testing

[mateuszbaran]

Yup, forgot to remove my editor's format-on-save option. I've reverted the formatting changes.

Thanks!

I have added tests, but they fail due to missing Base methods for FieldArray types. I guess those must be supplied by StaticArrays? Does this PR belong in StaticArrays instead?

I've checked and this indeed needs some methods from StaticArrays.jl. I think it would be much easier to add your methods to StaticArrays.jl.

[cadojo]

Closing in favor of JuliaArrays/StaticArrays.jl#1246. Thanks!