Void type

src/main/scala/fluence/hackethberlin/FuncDef.scala

@@ -3,15 +3,33 @@ package fluence.hackethberlin
 import fluence.hackethberlin.types.DataVyper
 import shapeless._
 
-class FuncDef[Args <: HList: DataVyper](
+class FuncDef[Args <: HList: DataVyper, Ret <: types.Type](
   name: String,
   argsDef: Args,
+  ret: Option[Ret],
   decorators: Set[Decorator] = Set.empty
 ) {
 
   def toVyper: String =
-    s"${decorators.map(_.toVyper).mkString("\n")}\ndef $name(${DataVyper[Args].mkString(argsDef, ", ")}):\n   body;\n"
+    s"${decorators.map(_.toVyper).mkString("\n")}\ndef $name(${DataVyper[Args].mkString(argsDef, ", ")})${ret.fold("")(" -> "+_.toVyper)}:\n   body;\n"
+
+  def @:(decorator: Decorator): FuncDef[Args, Ret] =
+    new FuncDef[Args, Ret](name, argsDef, ret, decorators + decorator)
+}
+
+object FuncDef {
+  def apply[Args <: HList : DataVyper, Ret <: types.Type](
+                                                           name: String,
+                                                           argsDef: Args,
+                                                           ret: Ret
+                                                         ): FuncDef[Args, Ret] =
+    new FuncDef(name, argsDef, Some(ret))
+
+
+  def apply[Args <: HList : DataVyper](
+                                                           name: String,
+                                                           argsDef: Args
+                                                         ): FuncDef[Args, types.Void] =
+    new FuncDef(name, argsDef, None)
 
-  def @:(decorator: Decorator): FuncDef[Args] =
-    new FuncDef[Args](name, argsDef, decorators + decorator)
 }

src/main/scala/fluence/hackethberlin/MakeVyperApp.scala

@@ -22,9 +22,10 @@ object MakeVyperApp extends App {
       ("struct2" → struct) :: HNil
   )
 
-  val func = new FuncDef(
+  val func = FuncDef(
     "myFunc",
-    ("address" → address) :: HNil
+    ("address" → address) :: HNil,
+    uint256
   )
 
   println(data.toVyper)

src/main/scala/fluence/hackethberlin/types/Void.scala

@@ -0,0 +1,8 @@
+package fluence.hackethberlin.types
+
+sealed trait Void extends Type
+
+// TODO: should it exist as an instance?
+case object Void extends Type {
+  override def toVyper: String = ""
+}