appears to be working

src/Flux.jl

@@ -1,9 +1,9 @@
 module Flux
 
 using MacroTools, Lazy, DataFlow, Juno
-import DataFlow: graphm, syntax, prewalk!, prewalk, postwalk, iscyclic,
+import DataFlow: graphm, syntax, prewalk!, postwalk!, prewalk, postwalk,
-  Constant, constant, isconstant, value, inputs, thread!, value, inputs,
+  iscyclic, Constant, constant, isconstant, Group, group, value, inputs,
-  Split, Group, group
+  thread!, value, inputs, Split
 import Juno: Tree, Row
 
 # Zero Flux Given

src/compiler/loops.jl

@@ -40,10 +40,10 @@ function collect_state(v::IVertex)
     isa(value(v), Offset) || return v
     if (i = findfirst(state, v[1])) == 0
       push!(state, v[1])
-      push!(offset, value(v).n)
+      push!(offset, max(0, -value(v).n))
       push!(default, get(value(v).default))
     else
-      offset[i] = min(offset[i], value(v).n)
+      offset[i] = max(offset[i], -value(v).n)
     end
     v
   end
@@ -56,29 +56,43 @@ function create_steps(v::IVertex, n)
   [bumpinputs(spliceinputs(v, hiddeninput(i))) for i = 1:n]
 end
 
+function getvar(n, step, steps, offset, default)
+  if step < 1
+    hiddeninput(sum(offset[1:n-1]) + 1 - step)
+  elseif step > length(steps)
+    constant(default[n])
+  else
+    steps[step][1,n]
+  end
+end
+
+function stateout(steps, offset, default)
+  outs = []
+  defaults = []
+  for i = 1:length(offset), j = 1:offset[i]
+    push!(outs, getvar(i, length(steps)-j+1, steps, offset, default))
+    push!(defaults, default[i])
+  end
+  group(outs...), defaults
+end
+
 function unrollgraph(v::IVertex, n)
   state, offset, default = collect_state(v)
   v = group(group(state...), v)
   steps = create_steps(v, n)
   for i = 1:n
     vars = inputs(steps[i][1])
-    prewalk!(steps[i]) do v
+    postwalk!(steps[i]) do v
       isa(value(v), Offset) || return v
-      stepid = value(v).n + i
       varid = findfirst(vars,v[1])
-      if stepid ∈ 1:n
+      getvar(varid, value(v).n + i, steps, offset, default)
-        steps[stepid][1,varid]
-      elseif stepid < 1
-        vertex(:input, constant(varid))
-      elseif stepid > n
-        constant(:output, constant(varid))
-      end
     end
   end
-  group(steps[end][1],group(map(x->x[2], steps)...))
+  state, defaults = stateout(steps, offset, default)
+  group(state,group(map(x->x[2], steps)...)), map(Flux.state, defaults)
 end
 
-unrollgraph(atomise(Chain(r,r)), 5) |> detuple |> syntax |> prettify
+unrollgraph(m, n) = unrollgraph(atomise(m), n)
 
 type Unrolled <: Model
   model
@@ -90,12 +104,3 @@ end
 graph(u::Unrolled) = u.graph
 
 unroll(model, n) = Unrolled(model, unrollgraph(model, n)..., n)
-
-@net type Recurrent
-  y
-  function (x)
-    y = σ(x, y{-1})
-  end
-end
-
-r = Recurrent(rand(5))