Update meta serialization rules

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 ### Changed
 - Meta to Json serializer now serializes a single item with index as an array. It is important for plotly integration.
+- Meta to Json serializes Meta without children a value as literal or array instead of an object with `@value` field.
 
 ### Deprecated
 

build.gradle.kts

@@ -9,7 +9,7 @@ plugins {
 
 allprojects {
     group = "space.kscience"
-    version = "0.6.2-dev-2"
+    version = "0.6.2-dev-3"
 }
 
 subprojects {

dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/JsonMetaFormat.kt

@@ -6,7 +6,7 @@ package space.kscience.dataforge.io
 import io.ktor.utils.io.core.Input
 import io.ktor.utils.io.core.Output
 import kotlinx.serialization.json.Json
-import kotlinx.serialization.json.JsonObject
+import kotlinx.serialization.json.JsonElement
 import space.kscience.dataforge.context.Context
 import space.kscience.dataforge.meta.Meta
 import space.kscience.dataforge.meta.descriptors.MetaDescriptor
@@ -19,8 +19,8 @@ import space.kscience.dataforge.meta.toMeta
 public class JsonMetaFormat(private val json: Json = DEFAULT_JSON) : MetaFormat {
 
     override fun writeMeta(output: Output, meta: Meta, descriptor: MetaDescriptor?) {
-        val jsonObject = meta.toJson(descriptor)
-        output.writeUtf8String(json.encodeToString(JsonObject.serializer(), jsonObject))
+        val jsonElement = meta.toJson(descriptor)
+        output.writeUtf8String(json.encodeToString(JsonElement.serializer(), jsonElement))
     }
 
     override fun readMeta(input: Input, descriptor: MetaDescriptor?): Meta {

dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/JsonMeta.kt

@@ -64,32 +64,31 @@ private fun Meta.toJsonWithIndex(descriptor: MetaDescriptor?, index: String?): J
     JsonObject(pairs.toMap())
 }
 
-public fun Meta.toJson(descriptor: MetaDescriptor? = null): JsonObject {
-    val element = toJsonWithIndex(descriptor, null)
-    return if (element is JsonObject) {
-        element
-    } else {
-        buildJsonObject {
-            put("@value", element)
-        }
-    }
+public fun Meta.toJson(descriptor: MetaDescriptor? = null): JsonElement {
+    return toJsonWithIndex(descriptor, null)
+//    val element = toJsonWithIndex(descriptor, null)
+//    return if (element is JsonObject) {
+//        element
+//    } else {
+//        buildJsonObject {
+//            put("@value", element)
+//        }
+//    }
 }
 
 /**
  * Convert a Json primitive to a [Value]
  */
-public fun JsonPrimitive.toValue(descriptor: MetaDescriptor?): Value {
-    return when (this) {
+public fun JsonPrimitive.toValue(descriptor: MetaDescriptor?): Value = when (this) {
     JsonNull -> Null
     else -> {
         if (isString) {
-                StringValue(content)
+            content.asValue()
         } else {
             //consider using LazyParse
             content.parseValue()
         }
     }
-    }
 }
 
 /**

dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/Value.kt

@@ -226,7 +226,7 @@ public fun <E : Enum<E>> E.asValue(): Value = EnumValue(this)
 
 
 /**
- * Create Value from String using closest match conversion
+ * Create Value from String using the closest match conversion
  */
 public fun String.parseValue(): Value {
 

dataforge-meta/src/commonTest/kotlin/space/kscience/dataforge/meta/MetaSerializationTest.kt

@@ -1,15 +1,45 @@
 package space.kscience.dataforge.meta
 
 import kotlinx.serialization.json.Json
+import space.kscience.dataforge.names.asName
 import kotlin.test.Test
 import kotlin.test.assertEquals
 
 class MetaSerializationTest {
 
     @Test
-    fun singleValueDeserialization(){
+    fun singleValueDeserialization() {
         val string = "ddd"
         val meta = Json.decodeFromString(MetaSerializer, string)
         assertEquals(string, meta.value?.string)
     }
+
+    @Test
+    fun complexMeta() {
+        val meta = Meta {
+            "a" put 28.3
+            "b" put doubleArrayOf(1.0, 2.0, 3.2)
+            "child" put Meta {
+                "a" put "aString"
+                "sns[0]" put Meta {
+                    "d" put 0
+                }
+                "sns[1]" put Meta {
+                    "d" put 1
+                }
+                setIndexed(
+                    "sns2".asName(),
+                    listOf(
+                        Meta { "d" put "first" },
+                        Meta("53")
+                    )
+                )
+            }
+        }
+
+        val string = Json.encodeToString(MetaSerializer, meta)
+        println(string)
+        val reconstructed = Json.decodeFromString(MetaSerializer, string)
+        assertEquals(meta, reconstructed)
+    }
 }