fix a todo, houdini-style

src/compiler/code.jl

@@ -1,5 +1,3 @@
-# TODO: proper escaping
-
 import DataFlow: mapconst, cse
 
 export @net, @ml
@@ -13,14 +11,20 @@ end
 
 function makegraph(graph, args)
   @assert length(args) == 1
-  mapconst(graph) do x
-    x == args[1] ? inputnode(1) :
-    isa(x, Offset) ? :(Offset($(Expr(:quote, x.name)), $(x.n), self.$(x.name))) :
-    x
+  graph = prewalk(graph) do v
+    isa(value(v), Constant) && value(v).value == args[1] ?
+      inputnode(1) :
+      v
+  end
+  graph = map(graph) do x
+    isa(x, Offset) ?
+      :(Offset($(Expr(:quote, x.name)), $(x.n), self.$(x.name))) :
+      x
   end
 end
 
 function build_type(T, params)
+  @esc T
   ex = quote
     type $T <: Model
       $(params...)
@@ -48,11 +52,11 @@ function process_type(ex)
   @assert length(args) == 1
   quote
     $(build_type(T, params))
-    (self::$T)($(args...),) = interpret(reifyparams(graph(self)), $(args...))
-    update!(self::$T, η) = $(map(p -> :(update!(self.$p, η)), pnames)...)
-    graph(self::$T) = $(DataFlow.constructor(makegraph(body, args)))
+    (self::$(esc(T)))($(args...),) = interpret(reifyparams(graph(self)), $(args...))
+    $(esc(:(Flux.update!(self::$T, η)))) = ($(map(p -> :(update!(self.$p, η)), pnames)...);)
+    $(esc(:(Flux.graph(self::$T)))) = $(DataFlow.constructor(mapconst(esc, makegraph(body, args))))
     nothing
-  end |> esc
+  end
 end
 
 macro net(ex)
@@ -64,12 +68,12 @@ end
 function process_anon(ex)
   args, body = process_func(ex)
   @assert length(args) == 1
-  :(Flux.Capacitor($(DataFlow.constructor(makegraph(body, args)))))
+  :(Flux.Capacitor($(DataFlow.constructor(mapconst(esc, makegraph(body, args))))))
 end
 
 macro ml(ex)
   @capture(shortdef(ex), ((xs__,) -> body_ ) | (f_(xs__,) = body_)) ||
     error("@ml requires a function definition")
   ex = process_anon(:($(xs...) -> $body))
-  (f == nothing ? :($f = $ex) : ex) |> esc
+  f == nothing ? :($(esc(f)) = $ex) : ex
 end