From d2b56b3812df702f22291a37dc51113f5d77b128 Mon Sep 17 00:00:00 2001
From: Juan Ignacio Polanco <jipolanc@gmail.com>
Date: Sun, 30 Aug 2020 16:40:51 +0200
Subject: [PATCH 1/6] Recursive implementation of getindex(::Vcat, idx)

---
 src/lazyconcat.jl | 38 +++++++++++++++++++++-----------------
 1 file changed, 21 insertions(+), 17 deletions(-)

diff --git a/src/lazyconcat.jl b/src/lazyconcat.jl
index 30613176..e1b19adf 100644
--- a/src/lazyconcat.jl
+++ b/src/lazyconcat.jl
@@ -43,28 +43,32 @@ function ==(a::Vcat{T,1,II}, b::Vcat{T,1,II}) where {T,II}
     all(arguments(a) .== arguments(b))
 end
 
-@propagate_inbounds @inline function vcat_getindex(f, k::Integer)
+@propagate_inbounds @inline vcat_getindex(f, k::Integer) =
+    vcat_getindex_recursive(f, (k, ), f.args...)
+
+@propagate_inbounds @inline vcat_getindex(f, k::Integer, j::Integer) =
+    vcat_getindex_recursive(f, (k, j), f.args...)
+
+@propagate_inbounds @inline function vcat_getindex_recursive(
+        f, idx::NTuple{1}, A, args...)
+    k, = idx
     T = eltype(f)
-    κ = k
-    for A in f.args
-        n = length(A)
-        κ ≤ n && return convert(T,A[κ])::T
-        κ -= n
-    end
-    throw(BoundsError(f, k))
+    n = length(A)
+    k ≤ n && return convert(T, A[k])::T
+    vcat_getindex_recursive(f, (k - n, ), args...)
 end
 
-@propagate_inbounds @inline function vcat_getindex(f, k::Integer, j::Integer)
+@propagate_inbounds @inline function vcat_getindex_recursive(
+        f, idx::NTuple{2}, A, args...)
+    k, j = idx
     T = eltype(f)
-    κ = k
-    for A in f.args
-        n = size(A,1)
-        κ ≤ n && return convert(T,A[κ,j])::T
-        κ -= n
-    end
-    throw(BoundsError(f, (k,j)))
+    n = size(A, 1)
+    k ≤ n && return convert(T, A[k, j])::T
+    vcat_getindex_recursive(f, (k - n, j), args...)
 end
 
+@inline vcat_getindex_recursive(f, idx) = throw(BoundsError(f, idx))
+
 @propagate_inbounds @inline getindex(f::Vcat{<:Any,1}, k::Integer) = vcat_getindex(f, k)
 @propagate_inbounds @inline getindex(f::Vcat{<:Any,2}, k::Integer, j::Integer) = vcat_getindex(f, k, j)
 getindex(f::Applied{DefaultArrayApplyStyle,typeof(vcat)}, k::Integer)= vcat_getindex(f, k)
@@ -957,4 +961,4 @@ function sub_paddeddata(::TriangularLayout{'U','N'}, S::SubArray{<:Any,1,<:Abstr
     P = parent(S)
     (kr,j) = parentindices(S)
     view(triangulardata(P), kr ∩ (1:j), j)
-end
\ No newline at end of file
+end

From bd138cac6f20da11dbf067efc4012134160233e9 Mon Sep 17 00:00:00 2001
From: Juan Ignacio Polanco <jipolanc@gmail.com>
Date: Sun, 30 Aug 2020 20:28:37 +0200
Subject: [PATCH 2/6] Recursive implementation of setindex!(::Vcat, idx)

---
 src/lazyconcat.jl | 45 ++++++++++++++++++++++++---------------------
 1 file changed, 24 insertions(+), 21 deletions(-)

diff --git a/src/lazyconcat.jl b/src/lazyconcat.jl
index e1b19adf..ed10766e 100644
--- a/src/lazyconcat.jl
+++ b/src/lazyconcat.jl
@@ -43,11 +43,8 @@ function ==(a::Vcat{T,1,II}, b::Vcat{T,1,II}) where {T,II}
     all(arguments(a) .== arguments(b))
 end
 
-@propagate_inbounds @inline vcat_getindex(f, k::Integer) =
-    vcat_getindex_recursive(f, (k, ), f.args...)
-
-@propagate_inbounds @inline vcat_getindex(f, k::Integer, j::Integer) =
-    vcat_getindex_recursive(f, (k, j), f.args...)
+@propagate_inbounds @inline vcat_getindex(f, idx::Vararg{Integer}) =
+    vcat_getindex_recursive(f, idx, f.args...)
 
 @propagate_inbounds @inline function vcat_getindex_recursive(
         f, idx::NTuple{1}, A, args...)
@@ -81,24 +78,30 @@ getindex(f::Applied{<:Any,typeof(vcat)}, k::Integer, j::Integer)= vcat_getindex(
 copy(f::Vcat) = Vcat(map(copy, f.args)...)
 map(::typeof(copy), f::Vcat) = Vcat(map.(copy, f.args)...)
 
-@propagate_inbounds @inline function setindex!(f::Vcat{T,1}, v, k::Integer) where T
-    κ = k
-    for A in f.args
-        n = length(A)
-        κ ≤ n && return setindex!(A, v, κ)
-        κ -= n
-    end
-    throw(BoundsError(f, k))
+@propagate_inbounds @inline vcat_setindex!(f, v, idx::Vararg{Integer}) =
+    vcat_setindex_recursive!(f, v, idx, f.args...)
+
+@propagate_inbounds @inline function vcat_setindex_recursive!(
+        f, v, idx::NTuple{1}, A, args...)
+    k, = idx
+    n = length(A)
+    k ≤ n && return setindex!(A, v, idx...)
+    vcat_setindex_recursive!(f, v, (k - n, ), args...)
 end
 
-@propagate_inbounds @inline function setindex!(f::Vcat{T,2}, v, k::Integer, j::Integer) where T
-    κ = k
-    for A in f.args
-        n = size(A,1)
-        κ ≤ n && return setindex!(A, v, κ, j)
-        κ -= n
-    end
-    throw(BoundsError(f, (k,j)))
+@propagate_inbounds @inline function vcat_setindex_recursive!(
+        f, v, idx::NTuple{2}, A, args...)
+    k, j = idx
+    n = length(A)
+    k ≤ n && return setindex!(A, v, idx...)
+    vcat_setindex_recursive!(f, v, (k - n, j), args...)
+end
+
+@inline vcat_setindex_recursive!(f, v, idx) = throw(BoundsError(f, idx))
+
+@propagate_inbounds @inline function setindex!(
+        f::Vcat{T,N}, v, idx::Vararg{Integer,N}) where {T,N}
+    vcat_setindex_recursive!(f, v, idx, f.args...)
 end
 
 reverse(f::Vcat{<:Any,1}) = Vcat((reverse(itr) for itr in reverse(f.args))...)

From 5b2f827b20eb8c7b4436d6e1e1b4e8fcd75f0f85 Mon Sep 17 00:00:00 2001
From: Juan Ignacio Polanco <jipolanc@gmail.com>
Date: Sun, 30 Aug 2020 20:47:08 +0200
Subject: [PATCH 3/6] Reimplement getindex/setindex! for Hcat

---
 src/lazyconcat.jl | 38 +++++++++++++++++++++++---------------
 1 file changed, 23 insertions(+), 15 deletions(-)

diff --git a/src/lazyconcat.jl b/src/lazyconcat.jl
index ed10766e..4f51b4a9 100644
--- a/src/lazyconcat.jl
+++ b/src/lazyconcat.jl
@@ -126,17 +126,20 @@ ndims(::Applied{<:Any,typeof(hcat)}) = 2
 size(f::Applied{<:Any,typeof(hcat)}) = (size(f.args[1],1), +(map(a -> size(a,2), f.args)...))
 Base.IndexStyle(::Type{<:Hcat}) where T = Base.IndexCartesian()
 
-function hcat_getindex(f, k::Integer, j::Integer)
+@inline hcat_getindex(f, k::Integer, j::Integer) =
+    hcat_getindex_recursive(f, (k, j), f.args...)
+
+@inline function hcat_getindex_recursive(
+        f, idx::NTuple{2}, A, args...)
+    k, j = idx
     T = eltype(f)
-    ξ = j
-    for A in f.args
-        n = size(A,2)
-        ξ ≤ n && return T(A[k,ξ])::T
-        ξ -= n
-    end
-    throw(BoundsError(f, (k,j)))
+    n = size(A, 2)
+    j ≤ n && return convert(T, A[k, j])::T
+    hcat_getindex_recursive(f, (k, j - n), args...)
 end
 
+@inline hcat_getindex_recursive(f, idx) = throw(BoundsError(f, idx))
+
 getindex(f::Hcat, k::Integer, j::Integer) = hcat_getindex(f, k, j)
 getindex(f::Applied{DefaultArrayApplyStyle,typeof(hcat)}, k::Integer, j::Integer)= hcat_getindex(f, k, j)
 getindex(f::Applied{<:Any,typeof(hcat)}, k::Integer, j::Integer)= hcat_getindex(f, k, j)
@@ -144,14 +147,19 @@ getindex(f::Applied{<:Any,typeof(hcat)}, k::Integer, j::Integer)= hcat_getindex(
 # since its mutable we need to make a copy
 copy(f::Hcat) = Hcat(map(copy, f.args)...)
 
+@inline function hcat_setindex_recursive!(
+        f, v, idx::NTuple{2}, A, args...)
+    k, j = idx
+    T = eltype(f)
+    n = size(A, 2)
+    j ≤ n && return setindex!(A, v, k, j)
+    hcat_setindex_recursive!(f, v, (k, j - n), args...)
+end
+
+@inline hcat_setindex_recursive!(f, v, idx) = throw(BoundsError(f, idx))
+
 function setindex!(f::Hcat{T}, v, k::Integer, j::Integer) where T
-    ξ = j
-    for A in f.args
-        n = size(A,2)
-        ξ ≤ n && return setindex!(A, v, k, ξ)
-        ξ -= n
-    end
-    throw(BoundsError(f, (k,j)))
+    hcat_setindex_recursive!(f, v, (k, j), f.args...)
 end
 
 

From 6353882a07f6c833b89d111ba4813d0018192667 Mon Sep 17 00:00:00 2001
From: Juan Ignacio Polanco <jipolanc@gmail.com>
Date: Sun, 30 Aug 2020 21:16:39 +0200
Subject: [PATCH 4/6] Fix setindex!(::Vcat{2}, ...)

---
 src/lazyconcat.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/lazyconcat.jl b/src/lazyconcat.jl
index 4f51b4a9..224872a1 100644
--- a/src/lazyconcat.jl
+++ b/src/lazyconcat.jl
@@ -92,7 +92,7 @@ end
 @propagate_inbounds @inline function vcat_setindex_recursive!(
         f, v, idx::NTuple{2}, A, args...)
     k, j = idx
-    n = length(A)
+    n = size(A, 1)
     k ≤ n && return setindex!(A, v, idx...)
     vcat_setindex_recursive!(f, v, (k - n, j), args...)
 end

From 0887f54e67eabca3efecc48dc9eed0f61e246bd7 Mon Sep 17 00:00:00 2001
From: Juan Ignacio Polanco <jipolanc@gmail.com>
Date: Sun, 30 Aug 2020 21:17:05 +0200
Subject: [PATCH 5/6] Add some type annotations

---
 src/lazyconcat.jl | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/lazyconcat.jl b/src/lazyconcat.jl
index 224872a1..84eff562 100644
--- a/src/lazyconcat.jl
+++ b/src/lazyconcat.jl
@@ -82,7 +82,7 @@ map(::typeof(copy), f::Vcat) = Vcat(map.(copy, f.args)...)
     vcat_setindex_recursive!(f, v, idx, f.args...)
 
 @propagate_inbounds @inline function vcat_setindex_recursive!(
-        f, v, idx::NTuple{1}, A, args...)
+        f::Vcat{T,1} where T, v, idx::NTuple{1}, A, args...)
     k, = idx
     n = length(A)
     k ≤ n && return setindex!(A, v, idx...)
@@ -90,7 +90,7 @@ map(::typeof(copy), f::Vcat) = Vcat(map.(copy, f.args)...)
 end
 
 @propagate_inbounds @inline function vcat_setindex_recursive!(
-        f, v, idx::NTuple{2}, A, args...)
+        f::Vcat{T,2} where T, v, idx::NTuple{2}, A, args...)
     k, j = idx
     n = size(A, 1)
     k ≤ n && return setindex!(A, v, idx...)

From e2cda407102f98b3e60cbe7c50cdbe56cd4b0519 Mon Sep 17 00:00:00 2001
From: Juan Ignacio Polanco <jipolanc@gmail.com>
Date: Tue, 1 Sep 2020 20:16:08 +0200
Subject: [PATCH 6/6] Remove unused function

---
 src/lazyconcat.jl | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/src/lazyconcat.jl b/src/lazyconcat.jl
index 84eff562..044ea15e 100644
--- a/src/lazyconcat.jl
+++ b/src/lazyconcat.jl
@@ -78,9 +78,6 @@ getindex(f::Applied{<:Any,typeof(vcat)}, k::Integer, j::Integer)= vcat_getindex(
 copy(f::Vcat) = Vcat(map(copy, f.args)...)
 map(::typeof(copy), f::Vcat) = Vcat(map.(copy, f.args)...)
 
-@propagate_inbounds @inline vcat_setindex!(f, v, idx::Vararg{Integer}) =
-    vcat_setindex_recursive!(f, v, idx, f.args...)
-
 @propagate_inbounds @inline function vcat_setindex_recursive!(
         f::Vcat{T,1} where T, v, idx::NTuple{1}, A, args...)
     k, = idx