basic tf backend

REQUIRE

@@ -1,2 +1,2 @@
 julia 0.5-
-MXNet
+TensorFlow

src/backend/backend.jl

@@ -1,7 +1,9 @@
 # TODO: load backends lazily
 
-include("mxnet/mxnet.jl")
+# include("mxnet/mxnet.jl")
+# using .MX
+# export mxnet
 
-using .MX
-
-export mxnet
+include("tensorflow/tensorflow.jl")
+using .TF
+export tf

src/backend/tensorflow/tensorflow.jl

@@ -0,0 +1,59 @@
+module TF
+
+using ..Flux, Flow, TensorFlow
+
+# Workaround for tensor display bug
+using Juno
+Media.render(::Juno.Clipboard, ::Tensor) = "Tensor()"
+
+cvalue(x) = x
+cvalue(c::Constant) = c.value
+cvalue(v::Vertex) = cvalue(value(v))
+
+graph(x::Tensor) = x
+
+matrixify(xs) = xs
+matrixify(xs::Vector) = xs[:,1:1]
+# TODO: detect variable reuse
+graph{T<:AArray}(p::Flux.Param{T}) = Variable(matrixify(p.x))
+
+function graph(model::Model, args...)
+  g = Flux.graph(model)
+  g = Flow.mapconst(g) do x
+    !isa(x, Flux.ModelInput) ? x :
+    isa(x.name, Integer) ? args[x.name] : getfield(model, x.name)
+  end
+  postwalk(g) do v
+    vertex(graph(cvalue(v), cvalue.(inputs(v))...))
+  end |> value
+end
+
+graph(::typeof(*), args...) = *(args...)
+graph(::typeof(+), args...) = +(args...)
+
+type Model
+  session::Session
+  inputs::Vector{Tensor}
+  graph::Tensor
+end
+
+Media.render(::Juno.Clipboard, ::Model) = "Flux.TF.Model()"
+
+function tf(model)
+  sess = Session()
+  input = placeholder(Float64)
+  g = graph(model, input)
+  run(sess, initialize_all_variables())
+  Model(sess, [input], g)
+end
+
+function (m::Model)(args...)
+  @assert length(args) == length(m.inputs)
+  run(m.session, m.graph, Dict(zip(m.inputs, args)))
+end
+
+# m = Flux.Dense(784, 10)
+# t = tf(m)
+# t(randn(784,1))
+
+end