reshape with Val (#907)

* reshape with Val

* check type inference

* Require at least one SOneTo in rdims

Co-authored-by: Mateusz Baran <mateuszbaran89@gmail.com>

* version bump to v1.2.2

Co-authored-by: Mateusz Baran <mateuszbaran89@gmail.com>

Author: jishnub

Project.toml

@@ -1,6 +1,6 @@
 name = "StaticArrays"
 uuid = "90137ffa-7385-5640-81b9-e52037218182"
-version = "1.2.1"
+version = "1.2.2"
 
 [deps]
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"

src/abstractarray.jl

@@ -204,6 +204,9 @@ end
 
 reshape(a::Array, ::Size{S}) where {S} = SizedArray{Tuple{S...}}(a)
 
+Base.rdims(out::Val{N}, inds::Tuple{SOneTo, Vararg{SOneTo}}) where {N} = Base.rdims(ntuple(i -> SOneTo(1), Val(N)), inds)
+Base.rdims(out::Tuple{Any}, inds::Tuple{SOneTo, Vararg{SOneTo}}) = (SOneTo(Base.rdims_trailing(inds...)),)
+
 @inline vec(a::StaticArray) = reshape(a, Size(prod(Size(typeof(a)))))
 
 @inline copy(a::StaticArray) = typeof(a)(Tuple(a))

test/SArray.jl

@@ -151,6 +151,22 @@
         @test (@inferred view(m, 1, 1, CartesianIndex(1))) === Scalar(m[1, 1])
 
         @test reverse(m) == reverse(reverse(collect(m), dims = 2), dims = 1)
+
+        m1 = reshape(m, Val(1))
+
+        m1 = @inferred reshape(m, Val(1))
+
+        @test m1 isa SVector
+        @test all(((x, y),) -> isequal(x,y), zip(m, m1))
+
+        m2 = @inferred reshape(m, Val(2))
+        @test m2 === m
+
+        m3 = @inferred reshape(m, Val(3))
+        @test eltype(m3) == eltype(m)
+        @test ndims(m3) == 3
+        @test size(m3) == (size(m)..., 1)
+        @test all(((x, y),) -> isequal(x,y), zip(m, m3))
     end
 
     @testset "promotion" begin