From 27bdfb84791fa73ee7439c6bc715205e33c50060 Mon Sep 17 00:00:00 2001
From: Takafumi Arakaki <aka.tkf@gmail.com>
Date: Sun, 13 Oct 2019 19:04:03 -0700
Subject: [PATCH] Add at-set!! macro

Note: I have to exclude get/set from ambiguity checks again.  So, a
part of commit 52218dd9d802729d2430cb35057adbc079601278 had to be
reverted.
---
 Project.toml          |  2 ++
 docs/Manifest.toml    | 10 +++++-
 docs/Project.toml     |  1 +
 src/BangBang.jl       |  5 +++
 src/setfield.jl       | 74 +++++++++++++++++++++++++++++++++++++++++++
 test/Manifest.toml    | 10 +++++-
 test/Project.toml     |  1 +
 test/test_aqua.jl     |  6 +++-
 test/test_setfield.jl | 16 ++++++++++
 9 files changed, 122 insertions(+), 3 deletions(-)
 create mode 100644 src/setfield.jl
 create mode 100644 test/test_setfield.jl

diff --git a/Project.toml b/Project.toml
index 06292ae2..e56769a4 100644
--- a/Project.toml
+++ b/Project.toml
@@ -10,6 +10,7 @@ Future = "9fa8497b-333b-5362-9e8d-4d0656e87820"
 InitialValues = "22cec73e-a1b8-11e9-2c92-598750a2cf9c"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 Requires = "ae029012-a4dd-5104-9daa-d747884805df"
+Setfield = "efcf1570-3423-57d1-acb7-fd33fddbac46"
 Tables = "bd369af6-aec1-5ad0-b16a-f7cc5008161c"
 ZygoteRules = "700de1a5-db45-46bc-99cf-38207098b444"
 
@@ -18,6 +19,7 @@ Compat = "2"
 ConstructionBase = "0.1"
 InitialValues = "0.2"
 Requires = "0.5"
+Setfield = "0.5.1"
 Tables = "0.2"
 ZygoteRules = "0.1, 0.2"
 julia = "1.0"
diff --git a/docs/Manifest.toml b/docs/Manifest.toml
index 1b5996e6..ba7012bd 100644
--- a/docs/Manifest.toml
+++ b/docs/Manifest.toml
@@ -1,7 +1,7 @@
 # This file is machine-generated - editing it directly is not advised
 
 [[BangBang]]
-deps = ["Compat", "ConstructionBase", "Future", "InitialValues", "LinearAlgebra", "Requires", "Tables", "ZygoteRules"]
+deps = ["Compat", "ConstructionBase", "Future", "InitialValues", "LinearAlgebra", "Requires", "Setfield", "Tables", "ZygoteRules"]
 path = ".."
 uuid = "198e06fe-97b7-11e9-32a5-e1d131e6ad66"
 version = "0.3.2-DEV"
@@ -197,6 +197,14 @@ uuid = "ea8e919c-243c-51af-8825-aaa63cd721ce"
 [[Serialization]]
 uuid = "9e88b42a-f829-5b0c-bbe9-9e923198166b"
 
+[[Setfield]]
+deps = ["ConstructionBase", "MacroTools"]
+git-tree-sha1 = "17d7a3334861580d46a4578fb60acefa1376a829"
+repo-rev = "master"
+repo-url = "https://github.com/jw3126/Setfield.jl.git"
+uuid = "efcf1570-3423-57d1-acb7-fd33fddbac46"
+version = "0.5.0"
+
 [[SharedArrays]]
 deps = ["Distributed", "Mmap", "Random", "Serialization"]
 uuid = "1a1011a3-84de-559e-8e89-a11a2f7dc383"
diff --git a/docs/Project.toml b/docs/Project.toml
index a9e0e987..5647e27f 100644
--- a/docs/Project.toml
+++ b/docs/Project.toml
@@ -3,5 +3,6 @@ BangBang = "198e06fe-97b7-11e9-32a5-e1d131e6ad66"
 ConstructionBase = "187b0558-2788-49d3-abe0-74a17ed4e7c9"
 DataFrames = "a93c6f00-e57d-5684-b7b6-d8193f3e46c0"
 Documenter = "e30172f5-a6a5-5a46-863b-614d45cd2de4"
+Setfield = "efcf1570-3423-57d1-acb7-fd33fddbac46"
 StructArrays = "09ab397b-f2b6-538f-b94a-2f83cf4a842a"
 TypedTables = "9d95f2ec-7b3d-5a63-8d20-e2491e220bb9"
diff --git a/src/BangBang.jl b/src/BangBang.jl
index b030d6f6..1a7aaa27 100644
--- a/src/BangBang.jl
+++ b/src/BangBang.jl
@@ -4,6 +4,7 @@ module BangBang
 @doc read(joinpath(dirname(@__DIR__), "README.md"), String) BangBang
 
 export @!,
+       @set!!,
        Empty,
        append!!,
        delete!!,
@@ -13,6 +14,7 @@ export @!,
        mul!!,
        pop!!,
        popfirst!!,
+       prefermutation,
        push!!,
        pushfirst!!,
        rmul!!,
@@ -45,6 +47,9 @@ include("macro.jl")
 include("dataframes_impl.jl")
 include("zygote.jl")
 
+include("setfield.jl")
+using .SetfieldImpl: @set!!, prefermutation
+
 function __init__()
     @require StaticArrays = "90137ffa-7385-5640-81b9-e52037218182" begin
         include("staticarrays.jl")
diff --git a/src/setfield.jl b/src/setfield.jl
new file mode 100644
index 00000000..e4304fe7
--- /dev/null
+++ b/src/setfield.jl
@@ -0,0 +1,74 @@
+module SetfieldImpl
+
+using ..BangBang: setproperty!!, setindex!!
+using Setfield: ComposedLens,
+                ConstIndexLens,
+                DynamicIndexLens,
+                IndexLens,
+                Lens,
+                PropertyLens,
+                Setfield,
+                set
+
+struct Lens!!{T <: Lens} <: Lens
+    lens::T
+end
+
+Setfield.get(obj, lens::Lens!!) = get(obj, lens.lens)
+
+# Default to immutable:
+Setfield.set(obj, lens::Lens!!, value) =
+    set(obj, lens.lens, value)
+
+Setfield.set(obj, lens::Lens!!{<:ComposedLens}, value) =
+    set(obj, Lens!!(lens.lens.outer) ∘ Lens!!(lens.lens.inner), value)
+
+Setfield.set(obj, ::Lens!!{<:PropertyLens{fieldname}}, value) where fieldname =
+    setproperty!!(obj, fieldname, value)
+
+const SupportedIndexLens = Union{
+    ConstIndexLens,
+    DynamicIndexLens,
+    IndexLens,
+}
+
+indicesfor(lens::IndexLens, _) = lens.indices
+indicesfor(::ConstIndexLens{I}, _) where I = I
+indicesfor(lens::DynamicIndexLens, obj) = lens.f(obj)
+
+Setfield.set(obj, lens::Lens!!{<:SupportedIndexLens}, value) =
+    setindex!!(obj, value, indicesfor(lens, obj)...)
+
+"""
+    prefermutation(lens::Lens) :: Lens
+
+See also [`@set!!`](@ref).
+"""
+prefermutation(lens::Lens) = Lens!!(lens)
+
+"""
+    @set!! assignment
+
+Like `Setfield.@set`, but prefer mutation if possible.
+
+# Examples
+```jldoctest
+julia> using BangBang
+
+julia> mutable struct Mutable
+           a
+           b
+       end
+
+julia> x = orig = Mutable((x=Mutable(1, 2), y=3), 4);
+
+julia> @set!! x.a.x.a = 10;
+
+julia> @assert x.a.x.a == orig.a.x.a == 10
+```
+"""
+macro set!!(ex)
+    Setfield.setmacro(prefermutation, ex, overwrite=true)
+end
+
+end  # module
diff --git a/test/Manifest.toml b/test/Manifest.toml
index f56a7e52..2b2c6a70 100644
--- a/test/Manifest.toml
+++ b/test/Manifest.toml
@@ -15,7 +15,7 @@ uuid = "4c88cf16-eb10-579e-8560-4a9242c79595"
 version = "0.4.0"
 
 [[BangBang]]
-deps = ["Compat", "ConstructionBase", "Future", "InitialValues", "LinearAlgebra", "Requires", "Tables", "ZygoteRules"]
+deps = ["Compat", "ConstructionBase", "Future", "InitialValues", "LinearAlgebra", "Requires", "Setfield", "Tables", "ZygoteRules"]
 path = ".."
 uuid = "198e06fe-97b7-11e9-32a5-e1d131e6ad66"
 version = "0.3.2-DEV"
@@ -301,6 +301,14 @@ uuid = "ea8e919c-243c-51af-8825-aaa63cd721ce"
 [[Serialization]]
 uuid = "9e88b42a-f829-5b0c-bbe9-9e923198166b"
 
+[[Setfield]]
+deps = ["ConstructionBase", "MacroTools"]
+git-tree-sha1 = "17d7a3334861580d46a4578fb60acefa1376a829"
+repo-rev = "master"
+repo-url = "https://github.com/jw3126/Setfield.jl.git"
+uuid = "efcf1570-3423-57d1-acb7-fd33fddbac46"
+version = "0.5.0"
+
 [[SharedArrays]]
 deps = ["Distributed", "Mmap", "Random", "Serialization"]
 uuid = "1a1011a3-84de-559e-8e89-a11a2f7dc383"
diff --git a/test/Project.toml b/test/Project.toml
index d8b0288b..e5bb3db3 100644
--- a/test/Project.toml
+++ b/test/Project.toml
@@ -9,6 +9,7 @@ IRTest = "c9680f28-2a59-47f6-98e4-d41620d42cd2"
 InitialValues = "22cec73e-a1b8-11e9-2c92-598750a2cf9c"
 InteractiveUtils = "b77e0a4c-d291-57a0-90e8-8db25a27a240"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
+Setfield = "efcf1570-3423-57d1-acb7-fd33fddbac46"
 StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 StructArrays = "09ab397b-f2b6-538f-b94a-2f83cf4a842a"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
diff --git a/test/test_aqua.jl b/test/test_aqua.jl
index 4c17e389..919d6dfc 100644
--- a/test/test_aqua.jl
+++ b/test/test_aqua.jl
@@ -2,7 +2,11 @@ module TestAqua
 
 using Aqua
 using BangBang
+using Setfield
 
-Aqua.test_all(BangBang)
+Aqua.test_all(
+    BangBang;
+    ambiguities=(exclude=[Base.get, Setfield.set, Setfield.modify],),
+)
 
 end  # module
diff --git a/test/test_setfield.jl b/test/test_setfield.jl
new file mode 100644
index 00000000..5089a052
--- /dev/null
+++ b/test/test_setfield.jl
@@ -0,0 +1,16 @@
+module TestSetfield
+
+include("preamble.jl")
+
+mutable struct Mutable
+    a
+    b
+end
+
+@testset begin
+    x = orig = Mutable((x=Mutable(1, 2), y=3), 4);
+    @set!! x.a.x.a = 10;
+    @test x.a.x.a == orig.a.x.a == 10
+end
+
+end  # module