diplomacy: move rendering properties to edges

FlipRendering { implicit p => ... } now changes the render direction of edges.
diplomatic NodeImps can specify a default render flip using the new 'render' method.

src/main/scala/diplomacy/LazyModule.scala

@@ -88,10 +88,11 @@ abstract class LazyModule()(implicit val p: Parameters)
     buf ++= s"""${pad}</node>\n"""
   }
   private def edgesGraphML(buf: StringBuilder, pad: String) {
-    nodes.filter(!_.omitGraphML) foreach { n => n.outputs.filter(!_._1.omitGraphML).foreach { case (o, l) =>
+    nodes.filter(!_.omitGraphML) foreach { n => n.outputs.filter(!_._1.omitGraphML).foreach { case (o, edge) =>
+      val RenderedEdge(colour, label, flipped) = edge
       buf ++= pad
       buf ++= "<edge"
-      if (o.reverse) {
+      if (flipped) {
         buf ++= s""" target=\"${index}::${n.index}\""""
         buf ++= s""" source=\"${o.lazyModule.index}::${o.index}\">"""
       } else {
@@ -99,13 +100,13 @@ abstract class LazyModule()(implicit val p: Parameters)
         buf ++= s""" target=\"${o.lazyModule.index}::${o.index}\">"""
       }
       buf ++= s"""<data key=\"e\"><y:PolyLineEdge>"""
-      if (o.reverse) {
+      if (flipped) {
         buf ++= s"""<y:Arrows source=\"standard\" target=\"none\"/>"""
       } else {
         buf ++= s"""<y:Arrows source=\"none\" target=\"standard\"/>"""
       }
-      buf ++= s"""<y:LineStyle color=\"${o.colour}\" type=\"line\" width=\"1.0\"/>"""
-      buf ++= s"""<y:EdgeLabel modelName=\"centered\" rotationAngle=\"270.0\">${l}</y:EdgeLabel>"""
+      buf ++= s"""<y:LineStyle color=\"${colour}\" type=\"line\" width=\"1.0\"/>"""
+      buf ++= s"""<y:EdgeLabel modelName=\"centered\" rotationAngle=\"270.0\">${label}</y:EdgeLabel>"""
       buf ++= s"""</y:PolyLineEdge></data></edge>\n"""
     } }
     children.filter(!_.omitGraphML).foreach { c => c.edgesGraphML(buf, pad) }

src/main/scala/diplomacy/Nodes.scala

@@ -28,6 +28,12 @@ private case object CardinalityInferenceDirectionKey extends
   Field[CardinalityInferenceDirection.T](CardinalityInferenceDirection.NO_INFERENCE)
 
 private case object MonitorsEnabled extends Field[Boolean](true)
+private case object RenderFlipped extends Field[Boolean](false)
+
+case class RenderedEdge(
+  colour:  String,
+  label:   String  = "",
+  flipped: Boolean = false) // prefer to draw the arrow pointing the opposite direction of other edges
 
 // DI = Downwards flowing Parameters received on the inner side of the node
 // UI = Upwards   flowing Parameters generated by the inner side of the node
@@ -37,14 +43,14 @@ trait InwardNodeImp[DI, UI, EI, BI <: Data]
 {
   def edgeI(pd: DI, pu: UI, p: Parameters, sourceInfo: SourceInfo): EI
   def bundleI(ei: EI): BI
+
+  // Edge functions
   def monitor(bundle: BI, edge: EI) {}
-  def colour: String
-  def reverse: Boolean = false
+  def render(e: EI): RenderedEdge
 
   // optional methods to track node graph
   def mixI(pu: UI, node: InwardNode[DI, UI, BI]): UI = pu // insert node into parameters
   def getO(pu: UI): Option[BaseNode] = None // most-outward common node
-  def labelI(ei: EI) = ""
 }
 
 // DO = Downwards flowing Parameters generated by the outer side of the node
@@ -59,7 +65,6 @@ trait OutwardNodeImp[DO, UO, EO, BO <: Data]
   // optional methods to track node graph
   def mixO(pd: DO, node: OutwardNode[DO, UO, BO]): DO = pd // insert node into parameters
   def getI(pd: DO): Option[BaseNode] = None // most-inward common node
-  def labelO(eo: EO) = ""
 }
 
 abstract class NodeImp[D, U, EO, EI, B <: Data]
@@ -75,9 +80,6 @@ abstract class SimpleNodeImp[D, U, E, B <: Data]
   def bundle(e: E): B
   def bundleO(e: E) = bundle(e)
   def bundleI(e: E) = bundle(e)
-  def label(e: E): String = ""
-  override def labelO(e: E) = label(e)
-  override def labelI(e: E) = label(e)
 }
 
 abstract class BaseNode(implicit val valName: ValName)
@@ -106,10 +108,8 @@ abstract class BaseNode(implicit val valName: ValName)
 
   protected[diplomacy] def gci: Option[BaseNode] // greatest common inner
   protected[diplomacy] def gco: Option[BaseNode] // greatest common outer
-  protected[diplomacy] def outputs: Seq[(BaseNode, String)]
-  protected[diplomacy] def inputs:  Seq[(BaseNode, String)]
-  protected[diplomacy] def colour:  String
-  protected[diplomacy] def reverse: Boolean
+  protected[diplomacy] def inputs:  Seq[(BaseNode, RenderedEdge)]
+  protected[diplomacy] def outputs: Seq[(BaseNode, RenderedEdge)]
 }
 
 object BaseNode
@@ -333,10 +333,11 @@ sealed abstract class MixedNode[DI, UI, EI, BI <: Data, DO, UO, EO, BO <: Data](
   }
 
   // meta-data for printing the node graph
-  protected[diplomacy] def colour  = inner.colour
-  protected[diplomacy] def reverse = inner.reverse
-  protected[diplomacy] def outputs = oPorts.map(_._2) zip edgesOut.map(e => outer.labelO(e))
-  protected[diplomacy] def inputs  = iPorts.map(_._2) zip edgesIn .map(e => inner.labelI(e))
+  protected[diplomacy] def inputs = (iPorts zip edgesIn) map { case ((_, n, p, _), e) =>
+    val re = inner.render(e)
+    (n, re.copy(flipped = re.flipped != p(RenderFlipped)))
+  }
+  protected[diplomacy] def outputs = oPorts map { case (i, n, _, _) => (n, n.inputs(i)._2) }
 }
 
 abstract class MixedCustomNode[DI, UI, EI, BI <: Data, DO, UO, EO, BO <: Data](

src/main/scala/diplomacy/package.scala

@@ -47,4 +47,7 @@ package object diplomacy
   def DisableMonitors[T](body: Parameters => T)(implicit p: Parameters) = body(p.alterPartial {
     case MonitorsEnabled => false
   })
+  def FlipRendering[T](body: Parameters => T)(implicit p: Parameters) = body(p.alterPartial {
+    case RenderFlipped => !p(RenderFlipped)
+  })
 }