introduce "boxing" constructors in place of converting ones (#12)

Do it like `Fill` from FillArrays.jl does it, instead of like `Array`
does it.

This also makes `wrap_in_0dim` redundant, so delete it.

Author: nsajko

README.md

@@ -31,7 +31,7 @@ The motivation for creating this package is:
     * `ZeroDimensionalArrayMutable` can be a good replacement. Examples:
         * make a `const` binding that's mutable:
           ```julia
-          const some_const_binding = ZeroDimensionalArrayMutable(fill(0.2))
+          const some_const_binding = ZeroDimensionalArrayMutable(0.2)
           ```
         * make a field within an immutable `struct` mutable (warning: it's usually more efficient to change the entire `struct` into a `mutable struct`)
           ```julia
@@ -45,11 +45,11 @@ The motivation for creating this package is:
         * https://github.com/JuliaLang/julia/issues/40369
         * https://discourse.julialang.org/t/dynamic-immutable-type/127168
 * to provide a wrapper type for treating a value as a scalar in broadcasting, something `Ref` is often used for:
-    * `ZeroDimensionalArrayImmutable` can be a good replacement. Construct one from its only element using the `wrap_in_0dim` function. Like this:
+    * `ZeroDimensionalArrayImmutable` can be a good replacement:
       ```julia-repl
       julia> using ZeroDimensionalArrays
 
-      julia> isa.(wrap_in_0dim([1,2,3]), [Array, Dict, Int])
+      julia> isa.(ZeroDimensionalArrayImmutable([1,2,3]), [Array, Dict, Int])
       3-element BitVector:
        1
        0

src/ZeroDimensionalArrays.jl

@@ -1,7 +1,6 @@
 module ZeroDimensionalArrays
 
 export
-    wrap_in_0dim,
     ZeroDimensionalArrayImmutable,
     ZeroDimensionalArrayMutable,
     ZeroDimensionalArrayMutableConstField
@@ -30,10 +29,6 @@ mutable struct ZeroDimensionalArrayMutableConstField{T} <: AbstractArray{T, 0}
     end
 end
 
-function wrap_in_0dim(v)
-    new_zero_dimensional_array_immutable(typeof(v), v)
-end
-
 const ZeroDimensionalArray = Union{
     ZeroDimensionalArrayImmutable,
     ZeroDimensionalArrayMutable,
@@ -84,12 +79,21 @@ function Base.only(a::ZeroDimensionalArray)
     a[]
 end
 
-function convert_from_other_array_to_given_eltype(::Type{Arr}, ::Type{T}, a::AbstractArray{<:Any, 0}) where {Arr <: ZeroDimensionalArray, T}
-    v = a[]
+function construct_given_eltype(::Type{Arr}, ::Type{T}, v) where {Arr <: ZeroDimensionalArray, T}
     c = type_to_constructor_function(Arr)
     c(T, v)
 end
 
+function construct(::Type{Arr}, v) where {Arr <: ZeroDimensionalArray}
+    T = typeof(v)
+    construct_given_eltype(Arr, T, v)
+end
+
+function convert_from_other_array_to_given_eltype(::Type{Arr}, ::Type{T}, a::AbstractArray{<:Any, 0}) where {Arr <: ZeroDimensionalArray, T}
+    v = a[]
+    construct_given_eltype(Arr, T, v)
+end
+
 function convert_from_other_array(::Type{Arr}, a::AbstractArray{<:Any, 0}) where {Arr <: ZeroDimensionalArray}
     T = eltype(a)
     convert_from_other_array_to_given_eltype(Arr, T, a)
@@ -107,11 +111,11 @@ for Arr ∈ (
         function Base.convert(::Type{$Arr{T}}, a::AbstractArray{<:Any, 0}) where {T}
             convert_from_other_array_to_given_eltype($Arr, T, a)
         end
-        function (::Type{$Arr})(a::AbstractArray{<:Any, 0})
-            convert_from_other_array($Arr, a)
+        function (::Type{$Arr})(v)
+            construct($Arr, v)
         end
-        function (::Type{$Arr{T}})(a::AbstractArray{<:Any, 0}) where {T}
-            convert_from_other_array_to_given_eltype($Arr, T, a)
+        function (::Type{$Arr{T}})(v) where {T}
+            construct_given_eltype($Arr, T, v)
         end
     end
 end

test/runtests.jl

@@ -13,25 +13,26 @@ using Aqua: Aqua
             ZeroDimensionalArrayMutable,
             ZeroDimensionalArrayMutableConstField,
         )
+            @test (@inferred Arr(0.3)) == (@inferred convert(Arr, fill(0.3)))
             @test isstructtype(Arr)
             @test Arr <: AbstractArray{<:Any, 0}
-            @test (@inferred Arr(fill(0.3))) isa Arr{Float64}
+            @test (@inferred Arr(0.3)) isa Arr{Float64}
             @test (@inferred convert(Arr, fill(0.3))) isa Arr{Float64}
-            @test (@inferred Arr{Float32}(fill(0.3))) isa Arr{Float32}
+            @test (@inferred Arr{Float32}(0.3)) isa Arr{Float32}
             @test (@inferred convert(Arr{Float32}, fill(0.3))) isa Arr{Float32}
-            @test () === @inferred propertynames(Arr(fill(0.3)))
-            @test only(fill(0.3)) === @inferred only(Arr(fill(0.3)))
-            @test fill(0.3)[] === @inferred Arr(fill(0.3))[]
-            @test fill(0.3)[1] === @inferred Arr(fill(0.3))[1]
-            @test @inferred isassigned(Arr(fill(0.3)))
-            @test @inferred isassigned(Arr(fill(0.3)), 1)
-            @test !(isassigned(Arr(fill(0.3)), 2))
-            @test (@inferred similar(Arr(fill(0.3)))) isa ZeroDimensionalArrayMutable{Float64}
-            @test (@inferred similar(Arr(fill(0.3)), Float32)) isa ZeroDimensionalArrayMutable{Float32}
-            @test fill(0.3) == Arr(fill(0.3))
-            @test Arr(fill(0.3)) == Arr(fill(0.3))
-            @test all(@inferred Arr(fill(0.3)) .== Arr(fill(0.3)))
-            @test (@inferred Arr(fill(0.3)) .+ [10, 20]) isa AbstractVector
+            @test () === @inferred propertynames(Arr(0.3))
+            @test only(fill(0.3)) === @inferred only(Arr(0.3))
+            @test fill(0.3)[] === @inferred Arr(0.3)[]
+            @test fill(0.3)[1] === @inferred Arr(0.3)[1]
+            @test @inferred isassigned(Arr(0.3))
+            @test @inferred isassigned(Arr(0.3), 1)
+            @test !(isassigned(Arr(0.3), 2))
+            @test (@inferred similar(Arr(0.3))) isa ZeroDimensionalArrayMutable{Float64}
+            @test (@inferred similar(Arr(0.3), Float32)) isa ZeroDimensionalArrayMutable{Float32}
+            @test fill(0.3) == Arr(0.3)
+            @test Arr(0.3) == Arr(0.3)
+            @test all(@inferred Arr(0.3) .== Arr(0.3))
+            @test (@inferred Arr(0.3) .+ [10, 20]) isa AbstractVector
         end
     end
 
@@ -40,13 +41,12 @@ using Aqua: Aqua
             @test @isdefined ZeroDimensionalArrayImmutable
             @test !ismutabletype(ZeroDimensionalArrayImmutable)
             @test isbitstype(ZeroDimensionalArrayImmutable{Float64})
-            @test ZeroDimensionalArrayImmutable(fill(7)) === @inferred wrap_in_0dim(7)
         end
         @testset "`ZeroDimensionalArrayMutable`" begin
             @test @isdefined ZeroDimensionalArrayMutable
             @test ismutabletype(ZeroDimensionalArrayMutable)
             @test (@inferred ZeroDimensionalArrayMutable{Float32}()) isa ZeroDimensionalArrayMutable{Float32}
-            @test let a = ZeroDimensionalArrayMutable(fill(0.3))
+            @test let a = ZeroDimensionalArrayMutable(0.3)
                 a[] = 0.7
                 only(a) === 0.7
             end