support Arrow on 1.9+ via pkg extension (#274)

* support Arrow on 1.9+ via pkg extension

* bump Julia compat to 1.9

* Revert "bump Julia compat to 1.9"

This reverts commit 13dfdc9.

* 1.6 compat

Project.toml

@@ -1,7 +1,7 @@
 name = "JSON3"
 uuid = "0f8b85d8-7281-11e9-16c2-39a750bddbf1"
 authors = ["Jacob Quinn <quinn.jacobd@gmail.com>"]
-version = "1.13.2"
+version = "1.14.0"
 
 [deps]
 Dates = "ade2ca70-3891-5945-98fb-dc099432e06a"
@@ -12,13 +12,22 @@ StructTypes = "856f2bd8-1eba-4b0a-8007-ebc267875bd4"
 UUIDs = "cf7118a7-6976-5b1a-9a39-7adc72f591a4"
 
 [compat]
+ArrowTypes = "2.2"
 Parsers = "0.3, 1, 2"
+PrecompileTools = "1"
 StructTypes = "1.10"
 julia = "1.6"
-PrecompileTools = "1"
+
+[extensions]
+JSON3ArrowExt = ["ArrowTypes"]
 
 [extras]
+Arrow = "69666777-d1a9-59fb-9406-91d4454c9d45"
+ArrowTypes = "31f734f8-188a-4ce0-8406-c8a06bd891cd"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [targets]
-test = ["Test"]
+test = ["Arrow", "Test"]
+
+[weakdeps]
+ArrowTypes = "31f734f8-188a-4ce0-8406-c8a06bd891cd"

ext/JSON3ArrowExt.jl

@@ -0,0 +1,17 @@
+module JSON3ArrowExt
+
+using JSON3
+using ArrowTypes
+
+const JSON3_ARROW_NAME = Symbol("JuliaLang.JSON3.Object")
+
+# It might looks strange to have this as a StructKind when JSON objects are
+# very dict-like, but the valtype is Any, which Arrow.jl really not like
+# and even if we add a
+# toarrow(d::JSON3.Object) d = Dict{String, Union{typeof.(values(d))...}
+# that does not seem to solve the problem.
+ArrowTypes.ArrowKind(::Type{<:JSON3.Object}) = ArrowTypes.StructKind()
+ArrowTypes.arrowname(::Type{<:JSON3.Object}) = JSON3_ARROW_NAME
+ArrowTypes.JuliaType(::Val{JSON3_ARROW_NAME}) = JSON3.Object
+
+end # module

test/arrow.jl

@@ -0,0 +1,45 @@
+using Arrow
+
+obj1 = JSON3.read("""
+{
+    "int": 1,
+    "float": 2.1
+}
+""")
+
+obj2 = JSON3.read("""
+{
+    "int": 1,
+    "float": 2.1,
+    "bool1": true,
+    "bool2": false,
+    "none": null,
+    "str": "\\"hey there sailor\\"",
+    "arr": [null, 1, "hey"],
+    "arr2": [1.2, 3.4, 5.6]
+}
+""")
+
+obj3 = JSON3.read("""
+{
+    "int": 1,
+    "float": 2.1,
+    "bool1": true,
+    "bool2": false,
+    "none": null,
+    "str": "\\"hey there sailor\\"",
+    "obj": {
+                "a": 1,
+                "b": null,
+                "c": [null, 1, "hey"],
+                "d": [1.2, 3.4, 5.6]
+            },
+    "arr": [null, 1, "hey"],
+    "arr2": [1.2, 3.4, 5.6]
+}
+""")
+
+tbl = (; json=[obj1, obj2, obj3])
+
+arrow = Arrow.Table(Arrow.tobuffer(tbl))
+@test tbl.json == arrow.json

test/runtests.jl

@@ -1103,4 +1103,8 @@ y = Vector{UndefGuy}(undef, 2)
 y[1] = x
 @test JSON3.write(y) == "[{\"id\":10},null]"
 
+@static if isdefined(Base, :get_extension)
+    @testset "Arrow" include("arrow.jl")
+end
+
 end # @testset "JSON3"