From 6894f28de201c2d0188b73d24e7e43a8b2a4340e Mon Sep 17 00:00:00 2001
From: Simone Carlo Surace <51025924+simsurace@users.noreply.github.com>
Date: Mon, 5 Feb 2024 20:45:44 +0100
Subject: [PATCH 1/6] Add support for `nothing`

I have been using this quite often to conditionally drop specific parameters.
---
 src/flatten.jl | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/flatten.jl b/src/flatten.jl
index 82d5b60..ce68646 100644
--- a/src/flatten.jl
+++ b/src/flatten.jl
@@ -19,6 +19,12 @@ function flatten end
 
 flatten(x) = flatten(Float64, x)
 
+function ParameterHandling.flatten(::Type{T}, ::Nothing) where {T<:Real} 
+    v = T[]
+    unflatten_to_Nothing(::Vector{T}) = nothing
+    return v, unflatten_to_Nothing
+end
+
 function flatten(::Type{T}, x::Integer) where {T<:Real}
     v = T[]
     unflatten_to_Integer(v::Vector{T}) = x

From 0d3a1d70c25519a2a6e11e7bcdbc1fe685658c43 Mon Sep 17 00:00:00 2001
From: Simone Carlo Surace <51025924+simsurace@users.noreply.github.com>
Date: Mon, 5 Feb 2024 20:49:01 +0100
Subject: [PATCH 2/6] Drop prefix

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

diff --git a/src/flatten.jl b/src/flatten.jl
index ce68646..a4c95a6 100644
--- a/src/flatten.jl
+++ b/src/flatten.jl
@@ -19,7 +19,7 @@ function flatten end
 
 flatten(x) = flatten(Float64, x)
 
-function ParameterHandling.flatten(::Type{T}, ::Nothing) where {T<:Real} 
+function flatten(::Type{T}, ::Nothing) where {T<:Real} 
     v = T[]
     unflatten_to_Nothing(::Vector{T}) = nothing
     return v, unflatten_to_Nothing

From bbfee5e6870bb9a9465ee9f00618315ed4d87143 Mon Sep 17 00:00:00 2001
From: Simone Carlo Surace <51025924+simsurace@users.noreply.github.com>
Date: Mon, 5 Feb 2024 21:06:55 +0100
Subject: [PATCH 3/6] Remove whitespace

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 src/flatten.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/flatten.jl b/src/flatten.jl
index a4c95a6..3caea79 100644
--- a/src/flatten.jl
+++ b/src/flatten.jl
@@ -19,7 +19,7 @@ function flatten end
 
 flatten(x) = flatten(Float64, x)
 
-function flatten(::Type{T}, ::Nothing) where {T<:Real} 
+function flatten(::Type{T}, ::Nothing) where {T<:Real}
     v = T[]
     unflatten_to_Nothing(::Vector{T}) = nothing
     return v, unflatten_to_Nothing

From 48b711bcc68cd9f4db57f15e3e59019dafcf002f Mon Sep 17 00:00:00 2001
From: Simone Carlo Surace <simsurace@gmx.net>
Date: Tue, 6 Feb 2024 10:57:15 +0100
Subject: [PATCH 4/6] Add tests

---
 test/flatten.jl | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/test/flatten.jl b/test/flatten.jl
index 47f4707..6b15e42 100644
--- a/test/flatten.jl
+++ b/test/flatten.jl
@@ -8,6 +8,11 @@
         end
     end
 
+    @testset "Nothing" begin
+        test_flatten_interface(nothing)
+        @test isempty(first(flatten(nothing)))
+    end
+
     @testset "AbstractArrays" begin
         test_flatten_interface(randn(10))
         test_flatten_interface(randn(5, 4))

From eecf86bbd4422aaa8cf1c13444083ee634ca4e2c Mon Sep 17 00:00:00 2001
From: Simone Carlo Surace <simsurace@gmx.net>
Date: Tue, 6 Feb 2024 10:57:32 +0100
Subject: [PATCH 5/6] Remove superfluous argument

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

diff --git a/src/flatten.jl b/src/flatten.jl
index 3caea79..1414cb0 100644
--- a/src/flatten.jl
+++ b/src/flatten.jl
@@ -27,7 +27,7 @@ end
 
 function flatten(::Type{T}, x::Integer) where {T<:Real}
     v = T[]
-    unflatten_to_Integer(v::Vector{T}) = x
+    unflatten_to_Integer(::Vector{T}) = x
     return v, unflatten_to_Integer
 end
 

From cbc556581f961584d171bac68d305fdcfa213e1a Mon Sep 17 00:00:00 2001
From: Simone Carlo Surace <simsurace@gmx.net>
Date: Tue, 6 Feb 2024 10:59:11 +0100
Subject: [PATCH 6/6] Bump version

---
 Project.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Project.toml b/Project.toml
index 7bfdc9d..103aae3 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "ParameterHandling"
 uuid = "2412ca09-6db7-441c-8e3a-88d5709968c5"
 authors = ["Invenia Technical Computing Corporation"]
-version = "0.4.7"
+version = "0.4.8"
 
 [deps]
 ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"