First implementation for protobuf converter

CHANGELOG.md

@@ -13,6 +13,8 @@
 ### Removed
 
 ### Fixed
+- Fixed NameToken parsing.
+- Top level string list meta conversion.
 
 ### Security
 

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

@@ -163,11 +163,15 @@ public fun JsonObject.toMeta(descriptor: MetaDescriptor? = null): SealedMeta {
 public fun JsonElement.toMeta(descriptor: MetaDescriptor? = null): SealedMeta = when (this) {
     is JsonPrimitive -> Meta(toValue(descriptor))
     is JsonObject -> toMeta(descriptor)
-    is JsonArray -> SealedMeta(null,
-        linkedMapOf<NameToken, SealedMeta>().apply {
-            addJsonElement(Meta.JSON_ARRAY_KEY, this@toMeta, null)
-        }
-    )
+    is JsonArray -> if (any { it is JsonObject }) {
+        SealedMeta(null,
+            linkedMapOf<NameToken, SealedMeta>().apply {
+                addJsonElement(Meta.JSON_ARRAY_KEY, this@toMeta, null)
+            }
+        )
+    } else{
+        Meta(map { it.toValueOrNull(descriptor) ?: kotlin.error("Unreachable: should not contain objects") }.asValue())
+    }
 }
 
 //

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

@@ -11,7 +11,7 @@ import space.kscience.dataforge.misc.DFExperimental
 /**
  * A converter of generic object to and from [Meta]
  */
-public interface MetaConverter<T>: MetaReader<T> {
+public interface MetaConverter<T> : MetaReader<T> {
 
     /**
      * A descriptor for resulting meta
@@ -116,6 +116,12 @@ public interface MetaConverter<T>: MetaReader<T> {
             override fun convert(obj: E): Meta = Meta(obj.asValue())
         }
 
+        public val stringList: MetaConverter<List<String>> = object : MetaConverter<List<String>> {
+            override fun convert(obj: List<String>): Meta = Meta(obj.map { it.asValue() }.asValue())
+
+            override fun readOrNull(source: Meta): List<String>? = source.stringList
+        }
+
         public fun <T> valueList(
             writer: (T) -> Value = { Value.of(it) },
             reader: (Value) -> T,

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

@@ -0,0 +1,17 @@
+package space.kscience.dataforge.meta
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class ConvertersTest {
+
+    @Test
+    fun stringListConversion() {
+        val list = listOf("A", "B", "C")
+        val meta = MetaConverter.stringList.convert(list)
+        val json = meta.toJson()
+        val reconstructedMeta = json.toMeta()
+        val reconstructed = MetaConverter.stringList.read(reconstructedMeta)
+        assertEquals(list,reconstructed)
+    }
+}