allow recursive subforms

supler/src/main/scala/org/supler/SuplerFieldMacros.scala

@@ -130,9 +130,9 @@ object SuplerFieldMacros {
 
     def newSubformField[T, ContU, U, Cont[_]](c: SubformContainer[ContU, U, Cont])
       (fieldName: String, read: T => Cont[U], write: (T, Cont[U]) => T,
-        embeddedForm: Form[U], createEmpty: Option[() => U]): SubformField[T, ContU, U, Cont] = {
+        embeddedForm: => Form[U], createEmpty: Option[() => U]): SubformField[T, ContU, U, Cont] = {
 
-      SubformField[T, ContU, U, Cont](c, fieldName, read, write, None, None, embeddedForm, createEmpty,
+      SubformField[T, ContU, U, Cont](c, fieldName, read, write, None, None, () => embeddedForm, createEmpty,
         SubformListRenderHint, AlwaysCondition, AlwaysCondition)
     }
 

supler/src/main/scala/org/supler/field/SubformField.scala

@@ -12,7 +12,7 @@ case class SubformField[T, ContU, U, Cont[_]](
   write: (T, Cont[U]) => T,
   label: Option[String],
   description: Option[String],
-  embeddedForm: Form[U],
+  embeddedFormF: () => Form[U],
   // if not specified, `embeddedForm.createEmpty` will be used
   createEmpty: Option[() => U],
   renderHint: RenderHint with SubformFieldCompatible,
@@ -21,6 +21,8 @@ case class SubformField[T, ContU, U, Cont[_]](
 
   import c._
 
+  lazy val embeddedForm = embeddedFormF()
+
   def label(newLabel: String): SubformField[T, ContU, U, Cont] = this.copy(label = Some(newLabel))
   def description(newDescription: String): SubformField[T, ContU, U, Cont] = this.copy(description = Some(newDescription))
 

supler/src/test/scala/org/supler/RecursiveTest.scala

@@ -0,0 +1,40 @@
+package org.supler
+
+import org.json4s.native._
+import org.scalatest._
+import Supler._
+
+class RecursiveTest extends FlatSpec with ShouldMatchers {
+  case class Person(name: String, children: List[Person])
+
+  def personForm: Form[Person] = form[Person](f => 
+    List(
+      f.field(_.name),
+      f.subform((p: Person) => p.children, personForm)
+    )
+  )
+
+  "subform" should "apply json values to a list field" in {
+
+  val jsonInOrder = parseJson("""
+    |{
+    | "name": "n",
+    | "children": [
+    |  {
+    |   "name": "c1"
+    |  },
+    |  {
+    |   "name": "c2"
+    |  }
+    | ]
+    |}
+  """.stripMargin)
+
+  // when
+  val result = personForm(Person("", Nil)).applyJSONValues(jsonInOrder)
+
+  // then
+  result.errors should be ('empty)
+  result.obj should be (Person("n", List(Person("c1", Nil), Person("c2", Nil))))
+  }
+}