From 51dc670d0715d1812db1dd88bce52c1f2037df25 Mon Sep 17 00:00:00 2001
From: mtfishman <mfishman@flatironinstitute.org>
Date: Fri, 20 Dec 2024 18:07:43 -0500
Subject: [PATCH] Add support for linear indexing

---
 Project.toml                  |  2 +-
 src/abstractarrayinterface.jl | 14 ++++++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/Project.toml b/Project.toml
index b009e02..a4ff79e 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "Derive"
 uuid = "a07dfc7f-7d04-4eb5-84cc-a97f051f655a"
 authors = ["ITensor developers <support@itensor.org> and contributors"]
-version = "0.3.5"
+version = "0.3.6"
 
 [deps]
 Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"
diff --git a/src/abstractarrayinterface.jl b/src/abstractarrayinterface.jl
index 485f6ab..72a790e 100644
--- a/src/abstractarrayinterface.jl
+++ b/src/abstractarrayinterface.jl
@@ -44,6 +44,13 @@ end
   return @interface interface getindex(a, Tuple(I)...)
 end
 
+# Linear indexing.
+@interface interface ::AbstractArrayInterface function Base.getindex(
+  a::AbstractArray, I::Int
+)
+  return @interface interface getindex(a, CartesianIndices(a)[I])
+end
+
 # TODO: Use `MethodError`?
 @interface ::AbstractArrayInterface function Base.setindex!(
   a::AbstractArray{<:Any,N}, value, I::Vararg{Int,N}
@@ -51,6 +58,13 @@ end
   return error("Not implemented.")
 end
 
+# Linear indexing.
+@interface interface ::AbstractArrayInterface function Base.setindex!(
+  a::AbstractArray, value, I::Int
+)
+  return @interface interface setindex!(a, value, CartesianIndices(a)[I])
+end
+
 # TODO: Make this more general, use `Base.to_index`.
 @interface interface::AbstractArrayInterface function Base.setindex!(
   a::AbstractArray{<:Any,N}, value, I::CartesianIndex{N}