Toward 💯 code coverage

README.md

@@ -10,8 +10,10 @@ and multiplication. This helps with the implementation of matrix-free methods
 for iterative solvers.
 
 The package has been designed with high-performance in mind, so should outperform
-the non-lazy analogues from Base. Please file an issue for any example that
-violates this.
+the non-lazy analogues from Base for many operations like `copyto!` and broadcasting.
+Some operations will be inherently slower due to extra computation, like `getindex`.
+Please file an issue for any examples that are significantly slower than their
+the analogue in Base.
 
 ## Concatenation
 

src/lazyconcat.jl

@@ -28,21 +28,23 @@ Base.IndexStyle(::Type{<:Vcat{T,1}}) where T = Base.IndexLinear()
 Base.IndexStyle(::Type{<:Vcat{T,2}}) where T = Base.IndexCartesian()
 
 function getindex(f::Vcat{T,1}, k::Integer) where T
+    κ = k
     for A in f.arrays
         n = length(A)
-        k ≤ n && return T(A[k])::T
-        k -= n
+        κ ≤ n && return T(A[κ])::T
+        κ -= n
     end
-    throw(BoundsError("attempt to access $length(f) Vcat array."))
+    throw(BoundsError(f, k))
 end
 
 function getindex(f::Vcat{T,2}, k::Integer, j::Integer) where T
+    κ = k
     for A in f.arrays
         n = size(A,1)
-        k ≤ n && return T(A[k,j])::T
-        k -= n
+        κ ≤ n && return T(A[κ,j])::T
+        κ -= n
     end
-    throw(BoundsError("attempt to access $length(f) Vcat array."))
+    throw(BoundsError(f, (k,j)))
 end
 
 reverse(f::Vcat{<:Any,1}) = Vcat((reverse(itr) for itr in reverse(f.arrays))...)
@@ -69,12 +71,13 @@ size(f::Hcat) = (size(f.arrays[1],1), +(map(a -> size(a,2), f.arrays)...))
 Base.IndexStyle(::Type{<:Hcat}) where T = Base.IndexCartesian()
 
 function getindex(f::Hcat{T}, k::Integer, j::Integer) where T
+    ξ = j
     for A in f.arrays
         n = size(A,2)
-        j ≤ n && return T(A[k,j])::T
-        j -= n
+        ξ ≤ n && return T(A[k,ξ])::T
+        ξ -= n
     end
-    throw(BoundsError("attempt to access $(size(f)) Hcat array."))
+    throw(BoundsError(f, (k,j)))
 end
 
 

test/runtests.jl

@@ -155,8 +155,9 @@ end
     b = Array{Float64}(undef, 6,10)
     @test @allocated(copyto!(b, A)) == 0
     @test b == vcat(A.arrays...)
-    
+
     A = Hcat(1:10, 2:11)
+    @test_throws BoundsError A[1,3]
     @test @inferred(size(A)) == (10,2)
     @test @inferred(A[5]) == @inferred(A[5,1]) == 5
     @test @inferred(A[11]) == @inferred(A[1,2]) == 2
@@ -166,6 +167,12 @@ end
     @test @allocated(copyto!(b, A)) == 0
     @test b == hcat(A.arrays...)
 
+    A = Hcat(Vector(1:10), Vector(2:11))
+    b = Array{Int}(undef, 10, 2)
+    copyto!(b, A)
+    @test b == hcat(A.arrays...)
+    @test @allocated(copyto!(b, A)) == 0
+
     A = Hcat(1, zeros(1,5))
     @test A == hcat(1, zeros(1,5))
 end