From 6eda27919030d9150a960010e3b57331e5359cac Mon Sep 17 00:00:00 2001
From: Mike J Innes <mike.j.innes@gmail.com>
Date: Tue, 14 Apr 2020 13:58:52 +0100
Subject: [PATCH] split out functor

---
 Manifest.toml  |  8 ++++++++
 Project.toml   |  1 +
 src/functor.jl | 37 +------------------------------------
 3 files changed, 10 insertions(+), 36 deletions(-)

diff --git a/Manifest.toml b/Manifest.toml
index bc74cb6e..672b3752 100644
--- a/Manifest.toml
+++ b/Manifest.toml
@@ -156,6 +156,14 @@ git-tree-sha1 = "869540e4367122fbffaace383a5bdc34d6e5e5ac"
 uuid = "f6369f11-7733-5829-9624-2563aa707210"
 version = "0.10.10"
 
+[[Functors]]
+deps = ["MacroTools"]
+git-tree-sha1 = "58dd223f9ad2601b0e9964fd65fa9d2c7219be41"
+repo-rev = "master"
+repo-url = "https://github.com/FluxML/Functors.jl"
+uuid = "d9f16b24-f501-4c13-a1f2-28368ffc5196"
+version = "0.1.0"
+
 [[GPUArrays]]
 deps = ["AbstractFFTs", "Adapt", "LinearAlgebra", "Printf", "Random", "Serialization"]
 git-tree-sha1 = "d586762b08dcda13228df8967119b9cb6f22ade5"
diff --git a/Project.toml b/Project.toml
index 1883d974..9ed0beae 100644
--- a/Project.toml
+++ b/Project.toml
@@ -9,6 +9,7 @@ CodecZlib = "944b1d66-785c-5afd-91f1-9de20f533193"
 Colors = "5ae59095-9a9b-59fe-a467-6f913c188581"
 CuArrays = "3a865a2d-5b23-5a0f-bc46-62713ec82fae"
 DelimitedFiles = "8bb1440f-4735-579b-a4ab-409b98df4dab"
+Functors = "d9f16b24-f501-4c13-a1f2-28368ffc5196"
 Juno = "e5e0dc1b-0480-54bc-9374-aad01c23163d"
 MacroTools = "1914dd2f-81c6-5fcd-8719-6d5c9610ff09"
 NNlib = "872c559c-99b0-510c-b3b7-b6c96a88d5cd"
diff --git a/src/functor.jl b/src/functor.jl
index 0d7c55f1..c97fd737 100644
--- a/src/functor.jl
+++ b/src/functor.jl
@@ -1,41 +1,6 @@
 import Adapt: adapt, adapt_storage
 using Zygote: IdSet
-
-functor(x) = (), _ -> x
-
-functor(x::Tuple) = x, y -> y
-functor(x::NamedTuple) = x, y -> y
-
-functor(x::AbstractArray) = x, y -> y
-functor(x::AbstractArray{<:Number}) = (), _ -> x
-
-function makefunctor(m::Module, T, fs = fieldnames(T))
-  @eval m begin
-    Flux.functor(x::$T) = ($([:($f=x.$f) for f in fs]...),), y -> $T(y...)
-  end
-end
-
-function functorm(T, fs = nothing)
-  fs == nothing || isexpr(fs, :tuple) || error("@functor T (a, b)")
-  fs = fs == nothing ? [] : [:($(map(QuoteNode, fs.args)...),)]
-  :(makefunctor(@__MODULE__, $(esc(T)), $(fs...)))
-end
-
-macro functor(args...)
-  functorm(args...)
-end
-
-isleaf(x) = functor(x)[1] === ()
-
-function fmap1(f, x)
-  func, re = functor(x)
-  re(map(f, func))
-end
-
-function fmap(f, x; cache = IdDict())
-  haskey(cache, x) && return cache[x]
-  cache[x] = isleaf(x) ? f(x) : fmap1(x -> fmap(f, x, cache = cache), x)
-end
+import Functors: @functor, functor, fmap
 
 trainable(m) = functor(m)[1]