Move Adapt to a weak dependency (#331)

* Move Adapt to a weak-dependency

* rename extension module

Author: jishnub

Project.toml

@@ -1,10 +1,16 @@
 name = "OffsetArrays"
 uuid = "6fe1bfb0-de20-5000-8ca7-80f57d26f881"
-version = "1.12.10"
+version = "1.13.0"
 
 [deps]
 Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"
 
+[weakdeps]
+Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"
+
+[extensions]
+OffsetArraysAdaptExt = "Adapt"
+
 [compat]
 Adapt = "2, 3, 4"
 Aqua = "0.8"
@@ -20,6 +26,7 @@ Test = "<0.0.1, 1"
 julia = "0.7, 1"
 
 [extras]
+Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"
 Aqua = "4c88cf16-eb10-579e-8560-4a9242c79595"
 CatIndices = "aafaddc9-749c-510e-ac4f-586e18779b91"
 DelimitedFiles = "8bb1440f-4735-579b-a4ab-409b98df4dab"
@@ -32,4 +39,4 @@ StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [targets]
-test = ["Aqua", "CatIndices", "DistributedArrays", "DelimitedFiles", "Documenter", "Test", "LinearAlgebra", "EllipsisNotation", "StaticArrays", "FillArrays"]
+test = ["Adapt", "Aqua", "CatIndices", "DistributedArrays", "DelimitedFiles", "Documenter", "EllipsisNotation", "FillArrays", "LinearAlgebra", "StaticArrays", "Test"]

ext/OffsetArraysAdaptExt.jl

@@ -0,0 +1,11 @@
+module OffsetArraysAdaptExt
+
+using OffsetArrays, Adapt
+
+##
+# Adapt allows for automatic conversion of CPU OffsetArrays to GPU OffsetArrays
+##
+import Adapt
+Adapt.adapt_structure(to, O::OffsetArray) = OffsetArrays.parent_call(x -> Adapt.adapt(to, x), O)
+
+end

src/OffsetArrays.jl

@@ -852,11 +852,9 @@ if VERSION <= v"1.7.0-DEV.400"
     Base._to_linear_index(A::OffsetArray) = first(LinearIndices(A))
 end
 
-##
-# Adapt allows for automatic conversion of CPU OffsetArrays to GPU OffsetArrays
-##
-import Adapt
-Adapt.adapt_structure(to, O::OffsetArray) = parent_call(x -> Adapt.adapt(to, x), O)
+if !isdefined(Base, :get_extension)
+  include("../ext/OffsetArraysAdaptExt.jl")
+end
 
 if Base.VERSION >= v"1.4.2"
     include("precompile.jl")