Refactor such that codecs carry the cursor history.

example/src/main/scala/com/ephox/argonaut/CodecDemo.scala

@@ -4,42 +4,92 @@ package argonaut
 import Argonaut._
 import scalaz._, Scalaz._
 
+/*
+=============
+JSON encoding
+-------------
+[
+  "Fred",
+  "40"
+]
+
+JSON decoding
+-------------
+Person(Fred,40)
+=============
+
+=============
+JSON encoding
+-------------
+{
+  "name" : "Fred",
+  "age" : "40"
+}
+
+JSON decoding
+-------------
+Person(Fred,40)
+=============
+*/
 object CodecDemo {
-  case class Person(name: String, age: Int, spouse: Option[Person], children: List[Person])
+  case class Person(name: String, age: Int)
 
   object Person {
-    implicit val DecodePerson: DecodeJson[Person] =
-      DecodeJson(j => j.array match {
-        case Some(n::a::s::c::Nil) =>
-          for {
-            nn <- n.jdecode[String]
-            aa <- a.jdecode[Int]
-            ss <- s.jdecode[Option[Person]]
-            cc <- c.jdecode[List[Person]]
-          } yield Person(nn, aa, ss, cc)
-        case _ => decodeError(j, "Person")
-      })
-
-    implicit val EncodePerson: EncodeJson[Person] =
-      EncodeJson({
-        case Person(n, a, s, c) => jArray(List(
-          n.jencode
-        , a.jencode
-        , s.jencode
-        , c.jencode
-        ))
-      }, "Person")
+    val fred = Person("Fred", 40)
+
+    trait Run {
+      implicit val DecodePerson: DecodeJson[Person]
+      implicit val EncodePerson: EncodeJson[Person]
+      def run: (String, String) = {
+        val enc = fred.jencode
+        val encP = enc.spaces2
+        val dec = enc.jdecode[Person]
+        val decP =
+          dec.result match {
+            case Left(e) => e.shows
+            case Right(p) => p.toString
+          }
+        (encP, decP)
+      }
+      def print {
+        val (enc, dec) = run
+        List(
+          "============="
+        , "JSON encoding"
+        , "-------------"
+        , enc
+        , ""
+        , "JSON decoding"
+        , "-------------"
+        , dec
+        , "============="
+        , ""
+        ) foreach println
+      }
+    }
+
+    object ArrayCodec extends Run {
+      implicit val DecodePerson: DecodeJson[Person] =
+        jdecode2(Person(_: String, _: Int)) setName "Person"
+
+      implicit val EncodePerson: EncodeJson[Person] =
+        jencode2((p: Person) => (p.name, p.age)) setName "Person"
+    }
+
+    object ObjectCodec extends Run {
+      implicit val DecodePerson: DecodeJson[Person] =
+        jdecode2L(Person(_: String, _: Int))("name", "age") setName "Person"
+
+      implicit val EncodePerson: EncodeJson[Person] =
+        jencode2L((p: Person) => (p.name, p.age))("name", "age") setName "Person"
+    }
+
   }
 
   def main(args: Array[String]) {
-    val children = List(Person("Bob", 10, None, Nil), Person("Jill", 12, None, Nil))
-    val fred = Person("Fred", 40, Some(Person("Mary", 41, None, children)), Person("Tom", 15, None, Nil) :: children)
-    val enc = fred.jencode
-    println(enc.spaces2)
-    val decode = enc.jdecode[Person]
-    println(decode.run match {
-      case Left(e) => e
-      case Right(p) => p.toString
-    })
+    import Person._
+
+    ArrayCodec.print
+    ObjectCodec.print
   }
 }