Fix IO after refactoring

dataforge-io/dataforge-io-yaml/src/main/kotlin/hep/dataforge/io/yaml/FrontMatterEnvelopeFormat.kt

@@ -105,11 +105,13 @@ class FrontMatterEnvelopeFormat(
         override fun readPartial(input: Input): PartialEnvelope =
             default.readPartial(input)
 
-        override fun Output.writeEnvelope(envelope: Envelope, metaFormatFactory: MetaFormatFactory, formatMeta: Meta): Unit =
+        override fun Output.writeEnvelope(
-            default.run { writeEnvelope(envelope, metaFormatFactory, formatMeta) }
+            envelope: Envelope,
+            metaFormatFactory: MetaFormatFactory,
+            formatMeta: Meta,
+        ): Unit = default.run { writeEnvelope(envelope, metaFormatFactory, formatMeta) }
 
-        override fun readObject(input: Input): Envelope =
+        override fun readObject(input: Input): Envelope = default.readObject(input)
-            default.readObject(input)
 
     }
 }

dataforge-io/src/commonMain/kotlin/hep/dataforge/io/IOFormat.kt

@@ -30,7 +30,7 @@ public interface IOFormat<T : Any> : MetaRepr {
     }
 }
 
-public fun <T : Any> Input.readWith(format: IOFormat<T>): T = format.run { readObject(this@readWith) }
+public fun <T : Any> Input.readWith(format: IOFormat<T>): T = format.readObject(this@readWith)
 
 /**
  * Read given binary as object using given format

dataforge-io/src/commonMain/kotlin/hep/dataforge/io/JsonMetaFormat.kt

@@ -12,7 +12,7 @@ import hep.dataforge.meta.toJson
 import hep.dataforge.meta.toMetaItem
 import kotlinx.io.Input
 import kotlinx.io.Output
-import kotlinx.io.readByteArray
+import kotlinx.io.text.readUtf8String
 import kotlinx.io.text.writeUtf8String
 import kotlinx.serialization.json.Json
 import kotlinx.serialization.json.JsonObject
@@ -24,7 +24,7 @@ public class JsonMetaFormat(private val json: Json = DEFAULT_JSON) : MetaFormat
 
     override fun writeMeta(output: Output, meta: Meta, descriptor: NodeDescriptor?) {
         val jsonObject = meta.toJson(descriptor)
-        output.writeUtf8String(this.json.encodeToString(JsonObject.serializer(), jsonObject))
+        output.writeUtf8String(json.encodeToString(JsonObject.serializer(), jsonObject))
     }
 
     override fun toMeta(): Meta = Meta {
@@ -32,7 +32,7 @@ public class JsonMetaFormat(private val json: Json = DEFAULT_JSON) : MetaFormat
     }
 
     override fun readMeta(input: Input, descriptor: NodeDescriptor?): Meta {
-        val str = input.readByteArray().decodeToString()
+        val str = input.readUtf8String()//readByteArray().decodeToString()
         val jsonElement = json.parseToJsonElement(str)
         val item = jsonElement.toMetaItem(descriptor)
         return item.node ?: Meta.EMPTY

dataforge-io/src/commonMain/kotlin/hep/dataforge/io/TaggedEnvelopeFormat.kt

@@ -18,7 +18,7 @@ import kotlinx.io.*
  */
 public class TaggedEnvelopeFormat(
     public val io: IOPlugin,
-    public val version: VERSION = VERSION.DF02
+    public val version: VERSION = VERSION.DF02,
 ) : EnvelopeFormat {
 
 //    private val metaFormat = io.metaFormat(metaFormatKey)
@@ -67,11 +67,7 @@ public class TaggedEnvelopeFormat(
         val metaFormat = io.resolveMetaFormat(tag.metaFormatKey)
             ?: error("Meta format with key ${tag.metaFormatKey} not found")
 
-        val meta: Meta = input.limit(tag.metaSize.toInt()).run {
+        val meta: Meta = metaFormat.readObject(input.limit(tag.metaSize.toInt()))
-            metaFormat.run {
-                readObject(input)
-            }
-        }
 
         val data = input.readBinary(tag.dataSize.toInt())
 
@@ -84,11 +80,8 @@ public class TaggedEnvelopeFormat(
         val metaFormat = io.resolveMetaFormat(tag.metaFormatKey)
             ?: error("Meta format with key ${tag.metaFormatKey} not found")
 
-        val meta: Meta = input.limit(tag.metaSize.toInt()).run {
+        val meta: Meta = metaFormat.readObject(input.limit(tag.metaSize.toInt()))
-            metaFormat.run {
+
-                readObject(input)
-            }
-        }
 
         return PartialEnvelope(meta, version.tagSize + tag.metaSize, tag.dataSize)
     }
@@ -96,7 +89,7 @@ public class TaggedEnvelopeFormat(
     private data class Tag(
         val metaFormatKey: Short,
         val metaSize: UInt,
-        val dataSize: ULong
+        val dataSize: ULong,
     )
 
     public enum class VERSION(public val tagSize: UInt) {
@@ -165,13 +158,13 @@ public class TaggedEnvelopeFormat(
         override fun readPartial(input: Input): PartialEnvelope =
             default.run { readPartial(input) }
 
-        override fun Output.writeEnvelope(envelope: Envelope, metaFormatFactory: MetaFormatFactory, formatMeta: Meta): Unit =
+        override fun Output.writeEnvelope(
-            default.run { writeEnvelope(envelope, metaFormatFactory, formatMeta) }
+            envelope: Envelope,
-
+            metaFormatFactory: MetaFormatFactory,
-        override fun readObject(input: Input): Envelope =
+            formatMeta: Meta,
-            default.run { readObject(input) }
+        ): Unit = default.run { writeEnvelope(envelope, metaFormatFactory, formatMeta) }
-
 
+        override fun readObject(input: Input): Envelope = default.readObject(input)
     }
 
 }

dataforge-io/src/commonMain/kotlin/hep/dataforge/io/TaglessEnvelopeFormat.kt

@@ -20,7 +20,7 @@ import kotlin.collections.set
  */
 public class TaglessEnvelopeFormat(
     public val io: IOPlugin,
-    public val meta: Meta = Meta.EMPTY
+    public val meta: Meta = Meta.EMPTY,
 ) : EnvelopeFormat {
 
     private val metaStart = meta[META_START_PROPERTY].string ?: DEFAULT_META_START
@@ -85,13 +85,9 @@ public class TaglessEnvelopeFormat(
             val metaFormat = properties[META_TYPE_PROPERTY]?.let { io.resolveMetaFormat(it) } ?: JsonMetaFormat
             val metaSize = properties[META_LENGTH_PROPERTY]?.toInt()
             meta = if (metaSize != null) {
-                input.limit(metaSize).run {
+                metaFormat.readObject(input.limit(metaSize))
-                    metaFormat.run { readObject(input) }
-                }
             } else {
-                metaFormat.run {
+                metaFormat.readObject(input)
-                    readObject(input)
-                }
             }
         }
 
@@ -150,9 +146,7 @@ public class TaglessEnvelopeFormat(
             val metaSize = properties[META_LENGTH_PROPERTY]?.toInt()
             meta = if (metaSize != null) {
                 offset += metaSize.toUInt()
-                input.limit(metaSize).run {
+                metaFormat.readObject(input.limit(metaSize))
-                    metaFormat.run { readObject(input) }
-                }
             } else {
                 error("Can't partially read an envelope with undefined meta size")
             }
@@ -203,11 +197,13 @@ public class TaglessEnvelopeFormat(
         override fun readPartial(input: Input): PartialEnvelope =
             default.run { readPartial(input) }
 
-        override fun Output.writeEnvelope(envelope: Envelope, metaFormatFactory: MetaFormatFactory, formatMeta: Meta): Unit =
+        override fun Output.writeEnvelope(
-            default.run { writeEnvelope(envelope, metaFormatFactory, formatMeta) }
+            envelope: Envelope,
+            metaFormatFactory: MetaFormatFactory,
+            formatMeta: Meta,
+        ): Unit = default.run { writeEnvelope(envelope, metaFormatFactory, formatMeta) }
 
-        override fun readObject(input: Input): Envelope =
+        override fun readObject(input: Input): Envelope = default.readObject(input)
-            default.run { readObject(input) }
 
         override fun peekFormat(io: IOPlugin, input: Input): EnvelopeFormat? {
             return try {

dataforge-io/src/commonTest/kotlin/hep/dataforge/io/EnvelopeFormatTest.kt

@@ -23,9 +23,9 @@ class EnvelopeFormatTest {
     @Test
     fun testTaggedFormat(){
         TaggedEnvelopeFormat.run {
-            val byteArray = this.toByteArray(envelope)
+            val byteArray = writeToByteArray(envelope)
             //println(byteArray.decodeToString())
-            val res = readByteArray(byteArray)
+            val res = readFromByteArray(byteArray)
             assertEquals(envelope.meta,res.meta)
             val double = res.data?.read {
                 readDouble()
@@ -37,9 +37,9 @@ class EnvelopeFormatTest {
     @Test
     fun testTaglessFormat(){
         TaglessEnvelopeFormat.run {
-            val byteArray = toByteArray(envelope)
+            val byteArray = writeToByteArray(envelope)
             //println(byteArray.decodeToString())
-            val res = readByteArray(byteArray)
+            val res = readFromByteArray(byteArray)
             assertEquals(envelope.meta,res.meta)
             val double = res.data?.read {
                 readDouble()

dataforge-io/src/commonTest/kotlin/hep/dataforge/io/MetaSerializerTest.kt

@@ -1,13 +1,19 @@
 package hep.dataforge.io
 
-import hep.dataforge.meta.*
+import hep.dataforge.meta.Meta
+import hep.dataforge.meta.MetaItem
+import hep.dataforge.meta.MetaSerializer
 import hep.dataforge.names.Name
 import hep.dataforge.names.toName
 import kotlinx.serialization.ExperimentalSerializationApi
 import kotlinx.serialization.cbor.Cbor
+import kotlinx.serialization.json.Json
 import kotlin.test.Test
 import kotlin.test.assertEquals
 
+val JSON_PRETTY: Json = Json { prettyPrint = true; useArrayPolymorphism = true }
+val JSON_PLAIN: Json = Json { prettyPrint = false; useArrayPolymorphism = true }
+
 class MetaSerializerTest {
     val meta = Meta {
         "a" put 22

dataforge-io/src/commonTest/kotlin/hep/dataforge/io/ioTestUtils.kt

@@ -3,5 +3,5 @@ package hep.dataforge.io
 import kotlinx.io.ByteArrayInput
 import kotlinx.io.use
 
-fun <T : Any> IOFormat<T>.toByteArray(obj: T): ByteArray = buildByteArray { writeObject(this, obj) }
+fun <T : Any> IOFormat<T>.writeToByteArray(obj: T): ByteArray = buildByteArray { writeObject(this, obj) }
-fun <T : Any> IOFormat<T>.readByteArray(array: ByteArray): T = ByteArrayInput(array).use { readObject(it) }
+fun <T : Any> IOFormat<T>.readFromByteArray(array: ByteArray): T = ByteArrayInput(array).use { readObject(it) }

dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/fileIO.kt

@@ -66,7 +66,11 @@ public inline fun <reified T : Any> IOPlugin.resolveIOFormat(): IOFormat<T>? {
  * Read file containing meta using given [formatOverride] or file extension to infer meta type.
  * If [path] is a directory search for file starting with `meta` in it
  */
-public fun IOPlugin.readMetaFile(path: Path, formatOverride: MetaFormat? = null, descriptor: NodeDescriptor? = null): Meta {
+public fun IOPlugin.readMetaFile(
+    path: Path,
+    formatOverride: MetaFormat? = null,
+    descriptor: NodeDescriptor? = null,
+): Meta {
     if (!Files.exists(path)) error("Meta file $path does not exist")
 
     val actualPath: Path = if (Files.isDirectory(path)) {
@@ -93,7 +97,7 @@ public fun IOPlugin.writeMetaFile(
     path: Path,
     meta: Meta,
     metaFormat: MetaFormatFactory = JsonMetaFormat,
-    descriptor: NodeDescriptor? = null
+    descriptor: NodeDescriptor? = null,
 ) {
     val actualPath = if (Files.isDirectory(path)) {
         path.resolve("@" + metaFormat.name.toString())
@@ -146,14 +150,15 @@ public val IOPlugin.Companion.DATA_FILE_NAME: String get() = "@data"
 public fun IOPlugin.readEnvelopeFile(
     path: Path,
     readNonEnvelopes: Boolean = false,
-    formatPeeker: IOPlugin.(Path) -> EnvelopeFormat? = IOPlugin::peekBinaryFormat
+    formatPeeker: IOPlugin.(Path) -> EnvelopeFormat? = IOPlugin::peekBinaryFormat,
 ): Envelope? {
     if (!Files.exists(path)) return null
 
     //read two-files directory
     if (Files.isDirectory(path)) {
-        val metaFile = Files.list(path).asSequence()
+        val metaFile = Files.list(path).asSequence().singleOrNull {
-            .singleOrNull { it.fileName.toString().startsWith(IOPlugin.META_FILE_NAME) }
+            it.fileName.toString().startsWith(IOPlugin.META_FILE_NAME)
+        }
 
         val meta = if (metaFile == null) {
             Meta.EMPTY
@@ -196,7 +201,7 @@ public fun IOPlugin.writeEnvelopeFile(
     path: Path,
     envelope: Envelope,
     envelopeFormat: EnvelopeFormat = TaggedEnvelopeFormat,
-    metaFormat: MetaFormatFactory? = null
+    metaFormat: MetaFormatFactory? = null,
 ) {
     path.rewrite {
         with(envelopeFormat) {
@@ -212,7 +217,7 @@ public fun IOPlugin.writeEnvelopeFile(
 fun IOPlugin.writeEnvelopeDirectory(
     path: Path,
     envelope: Envelope,
-    metaFormat: MetaFormatFactory = JsonMetaFormat
+    metaFormat: MetaFormatFactory = JsonMetaFormat,
 ) {
     if (!Files.exists(path)) {
         Files.createDirectories(path)

dataforge-io/src/jvmTest/kotlin/hep/dataforge/io/tcp/EnvelopeServerTest.kt

@@ -4,7 +4,7 @@ import hep.dataforge.context.Global
 import hep.dataforge.io.Envelope
 import hep.dataforge.io.Responder
 import hep.dataforge.io.TaggedEnvelopeFormat
-import hep.dataforge.io.toByteArray
+import hep.dataforge.io.writeToByteArray
 import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.runBlocking
 import kotlinx.io.writeDouble
@@ -18,7 +18,7 @@ import kotlin.time.ExperimentalTime
 @ExperimentalStdlibApi
 object EchoResponder : Responder {
     override suspend fun respond(request: Envelope): Envelope {
-        val string = TaggedEnvelopeFormat().run { toByteArray(request).decodeToString() }
+        val string = TaggedEnvelopeFormat().run { writeToByteArray(request).decodeToString() }
         println("ECHO:")
         println(string)
         return request

dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/JsonMeta.kt

@@ -4,6 +4,7 @@ package hep.dataforge.meta
 
 import hep.dataforge.meta.JsonMeta.Companion.JSON_ARRAY_KEY
 import hep.dataforge.meta.descriptors.ItemDescriptor
+import hep.dataforge.meta.descriptors.ItemDescriptor.Companion.DEFAULT_INDEX_KEY
 import hep.dataforge.meta.descriptors.NodeDescriptor
 import hep.dataforge.meta.descriptors.ValueDescriptor
 import hep.dataforge.names.NameToken
@@ -75,7 +76,7 @@ private fun Meta.toJsonWithIndex(descriptor: NodeDescriptor?, indexValue: String
 
 
     if (indexValue != null) {
-        val indexKey = descriptor?.indexKey ?: NodeDescriptor.DEFAULT_INDEX_KEY
+        val indexKey = descriptor?.indexKey ?: DEFAULT_INDEX_KEY
         elementMap[indexKey] = JsonPrimitive(indexValue)
     }
 
@@ -158,7 +159,7 @@ public class JsonMeta(private val json: JsonObject, private val descriptor: Node
                     )
                     map[key] = MetaItem.ValueItem(listValue)
                 } else value.forEachIndexed { index, jsonElement ->
-                    val indexKey = (itemDescriptor as? NodeDescriptor)?.indexKey ?: NodeDescriptor.DEFAULT_INDEX_KEY
+                    val indexKey = (itemDescriptor as? NodeDescriptor)?.indexKey ?: DEFAULT_INDEX_KEY
                     val indexValue: String = (jsonElement as? JsonObject)
                         ?.get(indexKey)?.jsonPrimitive?.contentOrNull
                         ?: index.toString() //In case index is non-string, the backward transformation will be broken.

dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Scheme.kt

@@ -1,9 +1,12 @@
 package hep.dataforge.meta
 
-import hep.dataforge.meta.descriptors.*
+import hep.dataforge.meta.descriptors.Described
+import hep.dataforge.meta.descriptors.NodeDescriptor
+import hep.dataforge.meta.descriptors.defaultItem
+import hep.dataforge.meta.descriptors.get
 import hep.dataforge.names.Name
 import hep.dataforge.names.NameToken
-import hep.dataforge.names.plus
+import hep.dataforge.names.asName
 
 /**
  * A base for delegate-based or descriptor-based scheme. [Scheme] has an empty constructor to simplify usage from [Specification].
@@ -30,21 +33,21 @@ public open class Scheme(
      * values if default value is unavailable.
      * Values from [defaultProvider] completely replace
      */
-    public open val defaultLayer: Meta get() = DefaultLayer(Name.EMPTY)
+    public open val defaultLayer: Meta get() = DefaultLayer()
 
     override fun toMeta(): Laminate = Laminate(config, defaultLayer)
 
-    private inner class DefaultLayer(val path: Name) : MetaBase() {
+    private inner class DefaultLayer : MetaBase() {
-        override val items: Map<NameToken, MetaItem<*>> =
+        override val items: Map<NameToken, MetaItem<*>> = buildMap {
-            (descriptor?.get(path) as? NodeDescriptor)?.items?.entries?.associate { (key, descriptor) ->
+            descriptor?.items?.forEach { (key, itemDescriptor) ->
                 val token = NameToken(key)
-                val fullName = path + token
+                val name = token.asName()
-                val item: MetaItem<*> = when (descriptor) {
+                val item = defaultProvider.getItem(name) ?: itemDescriptor.defaultItem()
-                    is ValueDescriptor -> getDefaultItem(fullName) ?: descriptor.defaultItem()
+                if (item != null) {
-                    is NodeDescriptor -> MetaItem.NodeItem(DefaultLayer(fullName))
+                    put(token, item)
                 }
-                token to item
+            }
-            } ?: emptyMap()
+        }
     }
 }
 
@@ -82,7 +85,7 @@ public open class MetaScheme(
     private val meta: Meta,
     override val descriptor: NodeDescriptor? = null,
     config: Config = Config(),
-) : Scheme(config, meta::get) {
+) : Scheme(config, meta) {
     override val defaultLayer: Meta get() = Laminate(meta, descriptor?.defaultItem().node)
 }
 

dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Specification.kt

@@ -23,12 +23,6 @@ public interface Specification<T : Configurable> {
  */
 public fun <T : Configurable> Specification<T>.update(config: Config, action: T.() -> Unit): T = wrap(config).apply(action)
 
-/**
- * Wrap a configuration using static meta as default
- */
-public fun <T : Configurable> Specification<T>.wrap(config: Config = Config(), default: Meta = Meta.EMPTY): T =
-    wrap(config, default)
-
 /**
  * Wrap a configuration using static meta as default
  */
@@ -37,7 +31,6 @@ public fun <T : Configurable> Specification<T>.wrap(source: Meta): T {
     return wrap(source.asConfig(), default)
 }
 
-
 /**
  * Apply specified configuration to configurable
  */

dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/descriptors/Described.kt

@@ -3,11 +3,11 @@ package hep.dataforge.meta.descriptors
 /**
  * An object which provides its descriptor
  */
-interface Described {
+public interface Described {
-    val descriptor: ItemDescriptor?
+    public val descriptor: ItemDescriptor?
 
-    companion object {
+    public companion object {
-        const val DESCRIPTOR_NODE = "@descriptor"
+        //public const val DESCRIPTOR_NODE: String = "@descriptor"
     }
 }
 

dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/descriptors/DescriptorMeta.kt

@@ -1,32 +1,48 @@
 package hep.dataforge.meta.descriptors
 
 import hep.dataforge.meta.Laminate
+import hep.dataforge.meta.Meta
 import hep.dataforge.meta.MetaBase
 import hep.dataforge.meta.MetaItem
 import hep.dataforge.names.NameToken
-import hep.dataforge.values.Null
 
 /**
- * A [Meta] that wraps a descriptor node
+ * A [Meta] that is constructed from [NodeDescriptor]
  */
-class DescriptorMeta(val descriptor: NodeDescriptor) : MetaBase() {
+private class DescriptorMeta(val descriptor: NodeDescriptor) : Meta, MetaBase() {
     override val items: Map<NameToken, MetaItem<*>>
-        get() = descriptor.items.entries.associate { entry ->
+        get() = buildMap {
-            NameToken(entry.key) to entry.value.defaultItem()
+            descriptor.items.forEach { (token, descriptorItem) ->
+                val item = descriptorItem.defaultItem()
+                if (item != null) {
+                    put(NameToken(token), item)
+                }
+            }
         }
 }
 
-fun NodeDescriptor.buildDefaultMeta() = Laminate(default, DescriptorMeta(this))
+/**
+ * Generate a laminate representing default item set generated by this descriptor
+ */
+public fun NodeDescriptor.defaultMeta(): Laminate = Laminate(default, DescriptorMeta(this))
 
-fun NodeDescriptor.defaultItem(): MetaItem.NodeItem<*> =
+/**
-    MetaItem.NodeItem(buildDefaultMeta())
+ * Build a default [MetaItem.NodeItem] from this node descriptor
+ */
+internal fun NodeDescriptor.defaultItem(): MetaItem.NodeItem<*> =
+    MetaItem.NodeItem(defaultMeta())
 
-fun ValueDescriptor.defaultItem(): MetaItem.ValueItem = MetaItem.ValueItem(default ?: Null)
+/**
+ * Build a default [MetaItem.ValueItem] from this descriptor
+ */
+internal fun ValueDescriptor.defaultItem(): MetaItem.ValueItem? {
+    return MetaItem.ValueItem(default ?: return null)
+}
 
 /**
  * Build a default [MetaItem] from descriptor.
  */
-fun ItemDescriptor.defaultItem(): MetaItem<*> {
+public fun ItemDescriptor.defaultItem(): MetaItem<*>? {
     return when (this) {
         is ValueDescriptor -> defaultItem()
         is NodeDescriptor -> defaultItem()

dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/descriptors/ItemDescriptor.kt

@@ -4,29 +4,26 @@ import hep.dataforge.meta.*
 import hep.dataforge.names.*
 import hep.dataforge.values.*
 
+/**
+ * A common parent for [ValueDescriptor] and [NodeDescriptor]. Describes a single [MetaItem] or a group of same-name-siblings.
+ */
 @DFBuilder
-sealed class ItemDescriptor(val config: Config) {
+public sealed class ItemDescriptor(public val config: Config) {
 
     /**
      * True if same name siblings with this name are allowed
-     *
-     * @return
      */
-    var multiple: Boolean by config.boolean(false)
+    public var multiple: Boolean by config.boolean(false)
 
     /**
-     * The item description
+     * The item description text
-     *
-     * @return
      */
-    var info: String? by config.string()
+    public var info: String? by config.string()
 
     /**
      * True if the item is required
-     *
-     * @return
      */
-    abstract var required: Boolean
+    public abstract var required: Boolean
 
 
     /**
@@ -34,29 +31,29 @@ sealed class ItemDescriptor(val config: Config) {
      *
      * @return
      */
-    var attributes by config.node()
+    public var attributes: Config? by config.node()
-}
 
-/**
+    /**
- * Configure attributes of the descriptor
+     * An index field by which this node is identified in case of same name siblings construct
- */
+     */
-fun ItemDescriptor.attributes(block: Config.() -> Unit) {
+    public var indexKey: String by config.string(DEFAULT_INDEX_KEY)
-    (attributes ?: Config().also { this.attributes = it }).apply(block)
-}
 
-/**
+    public companion object{
- * Set specific attribute in the descriptor
+        public const val DEFAULT_INDEX_KEY: String = "@index"
- */
-fun ItemDescriptor.setAttribute(name: Name, value: Any?) {
-    attributes {
-        set(name, value)
     }
 }
 
+/**
+ * Configure attributes of the descriptor, creating an attributes node if needed.
+ */
+public fun ItemDescriptor.attributes(block: Config.() -> Unit) {
+    (attributes ?: Config().also { this.attributes = it }).apply(block)
+}
+
 /**
  * Check if given item suits the descriptor
  */
-fun ItemDescriptor.validateItem(item: MetaItem<*>?): Boolean {
+public fun ItemDescriptor.validateItem(item: MetaItem<*>?): Boolean {
     if (item == null) return !required
     return when (this) {
         is ValueDescriptor -> isAllowedValue(item.value ?: return false)
@@ -73,7 +70,7 @@ fun ItemDescriptor.validateItem(item: MetaItem<*>?): Boolean {
  * @author Alexander Nozik
  */
 @DFBuilder
-class NodeDescriptor(config: Config = Config()) : ItemDescriptor(config) {
+public class NodeDescriptor(config: Config = Config()) : ItemDescriptor(config) {
     init {
         config[IS_NODE_KEY] = true
     }
@@ -90,14 +87,12 @@ class NodeDescriptor(config: Config = Config()) : ItemDescriptor(config) {
      *
      * @return
      */
-    var default by config.node()
+    public var default: Config? by config.node()
 
     /**
-     * An index field by which this node is identified in case of same name siblings construct
+     * The map of children item descriptors (both nodes and values)
      */
-    var indexKey by config.string(DEFAULT_INDEX_KEY)
+    public val items: Map<String, ItemDescriptor>
-
-    val items: Map<String, ItemDescriptor>
         get() = config.getIndexed(ITEM_KEY).mapValues { (_, item) ->
             val node = item.node ?: error("Node descriptor must be a node")
             if (node[IS_NODE_KEY].boolean == true) {
@@ -111,7 +106,7 @@ class NodeDescriptor(config: Config = Config()) : ItemDescriptor(config) {
      * The map of children node descriptors
      */
     @Suppress("UNCHECKED_CAST")
-    val nodes: Map<String, NodeDescriptor>
+    public val nodes: Map<String, NodeDescriptor>
         get() = config.getIndexed(ITEM_KEY).entries.filter {
             it.value.node[IS_NODE_KEY].boolean == true
         }.associate { (name, item) ->
@@ -120,9 +115,9 @@ class NodeDescriptor(config: Config = Config()) : ItemDescriptor(config) {
         }
 
     /**
-     * The list of value descriptors
+     * The list of children value descriptors
      */
-    val values: Map<String, ValueDescriptor>
+    public val values: Map<String, ValueDescriptor>
         get() = config.getIndexed(ITEM_KEY).entries.filter {
             it.value.node[IS_NODE_KEY].boolean != true
         }.associate { (name, item) ->
@@ -154,39 +149,43 @@ class NodeDescriptor(config: Config = Config()) : ItemDescriptor(config) {
         config[token] = descriptor.config
     }
 
-    fun item(name: Name, descriptor: ItemDescriptor) {
+    public fun item(name: Name, descriptor: ItemDescriptor) {
         buildNode(name.cutLast()).newItem(name.lastOrNull().toString(), descriptor)
     }
 
-    fun item(name: String, descriptor: ItemDescriptor) {
+    public fun item(name: String, descriptor: ItemDescriptor) {
         item(name.toName(), descriptor)
     }
 
-    fun node(name: Name, block: NodeDescriptor.() -> Unit) {
+    /**
+     * Create and configure a child node descriptor
+     */
+    public fun node(name: Name, block: NodeDescriptor.() -> Unit) {
         item(name, NodeDescriptor().apply(block))
     }
 
-    fun node(name: String, block: NodeDescriptor.() -> Unit) {
+    public fun node(name: String, block: NodeDescriptor.() -> Unit) {
         node(name.toName(), block)
     }
 
-    fun value(name: Name, block: ValueDescriptor.() -> Unit) {
+    /**
+     * Create and configure child value descriptor
+     */
+    public fun value(name: Name, block: ValueDescriptor.() -> Unit) {
         require(name.length >= 1) { "Name length for value descriptor must be non-empty" }
         item(name, ValueDescriptor().apply(block))
     }
 
-    fun value(name: String, block: ValueDescriptor.() -> Unit) {
+    public fun value(name: String, block: ValueDescriptor.() -> Unit) {
         value(name.toName(), block)
     }
 
-    companion object {
+    public companion object {
 
-        val ITEM_KEY = "item".asName()
+        internal val ITEM_KEY: Name = "item".asName()
-        val IS_NODE_KEY = "@isNode".asName()
+        internal val IS_NODE_KEY: Name = "@isNode".asName()
 
-        const val DEFAULT_INDEX_KEY = "@index"
+        public inline operator fun invoke(block: NodeDescriptor.() -> Unit): NodeDescriptor = NodeDescriptor().apply(block)
-
-        inline operator fun invoke(block: NodeDescriptor.() -> Unit) = NodeDescriptor().apply(block)
 
         //TODO infer descriptor from spec
     }
@@ -195,7 +194,7 @@ class NodeDescriptor(config: Config = Config()) : ItemDescriptor(config) {
 /**
  * Get a descriptor item associated with given name or null if item for given name not provided
  */
-operator fun ItemDescriptor.get(name: Name): ItemDescriptor? {
+public operator fun ItemDescriptor.get(name: Name): ItemDescriptor? {
     if (name.isEmpty()) return this
     return when (this) {
         is ValueDescriptor -> null // empty name already checked
@@ -203,7 +202,7 @@ operator fun ItemDescriptor.get(name: Name): ItemDescriptor? {
     }
 }
 
-operator fun ItemDescriptor.get(name: String): ItemDescriptor? = get(name.toName())
+public operator fun ItemDescriptor.get(name: String): ItemDescriptor? = get(name.toName())
 
 /**
  * A descriptor for meta value
@@ -213,7 +212,7 @@ operator fun ItemDescriptor.get(name: String): ItemDescriptor? = get(name.toName
  * @author Alexander Nozik
  */
 @DFBuilder
-class ValueDescriptor(config: Config = Config()) : ItemDescriptor(config) {
+public class ValueDescriptor(config: Config = Config()) : ItemDescriptor(config) {
 
     /**
      * True if the value is required
@@ -227,9 +226,9 @@ class ValueDescriptor(config: Config = Config()) : ItemDescriptor(config) {
      *
      * @return
      */
-    var default: Value? by config.value()
+    public var default: Value? by config.value()
 
-    fun default(v: Any) {
+    public fun default(v: Any) {
         this.default = Value.of(v)
     }
 
@@ -238,9 +237,9 @@ class ValueDescriptor(config: Config = Config()) : ItemDescriptor(config) {
      *
      * @return
      */
-    var type: List<ValueType>? by config.listValue { ValueType.valueOf(it.string) }
+    public var type: List<ValueType>? by config.listValue { ValueType.valueOf(it.string) }
 
-    fun type(vararg t: ValueType) {
+    public fun type(vararg t: ValueType) {
         this.type = listOf(*t)
     }
 
@@ -251,7 +250,7 @@ class ValueDescriptor(config: Config = Config()) : ItemDescriptor(config) {
      * @param value
      * @return
      */
-    fun isAllowedValue(value: Value): Boolean {
+    public fun isAllowedValue(value: Value): Boolean {
         return (type?.let { it.contains(ValueType.STRING) || it.contains(value.type) } ?: true)
                 && (allowedValues.isEmpty() || allowedValues.contains(value))
     }
@@ -262,7 +261,7 @@ class ValueDescriptor(config: Config = Config()) : ItemDescriptor(config) {
      *
      * @return
      */
-    var allowedValues: List<Value> by config.item().convert(
+    public var allowedValues: List<Value> by config.item().convert(
         reader = {
             val value = it.value
             when {
@@ -279,7 +278,7 @@ class ValueDescriptor(config: Config = Config()) : ItemDescriptor(config) {
     /**
      * Allow given list of value and forbid others
      */
-    fun allow(vararg v: Any) {
+    public fun allow(vararg v: Any) {
         this.allowedValues = v.map { Value.of(it) }
     }
 }
@@ -287,7 +286,7 @@ class ValueDescriptor(config: Config = Config()) : ItemDescriptor(config) {
 /**
  * Merge two node descriptors into one using first one as primary
  */
-operator fun NodeDescriptor.plus(other: NodeDescriptor): NodeDescriptor {
+public operator fun NodeDescriptor.plus(other: NodeDescriptor): NodeDescriptor {
     return NodeDescriptor().apply {
         config.update(other.config)
         config.update(this@plus.config)

dataforge-meta/src/commonTest/kotlin/hep/dataforge/meta/descriptors/DescriptorTest.kt

@@ -36,7 +36,7 @@ class DescriptorTest {
 
     @Test
     fun testDefaultMetaNode(){
-        val meta = descriptor.buildDefaultMeta()
+        val meta = descriptor.defaultMeta()
         assertEquals(false, meta["aNode.otherNode.otherValue"].boolean)
     }
 }

dataforge-meta/src/commonTest/kotlin/hep/dataforge/meta/serialization.kt

@@ -1,6 +0,0 @@
-package hep.dataforge.meta
-
-import kotlinx.serialization.json.Json
-
-public val JSON_PRETTY: Json = Json { prettyPrint = true; useArrayPolymorphism = true }
-public val JSON_PLAIN: Json = Json { prettyPrint = false; useArrayPolymorphism = true }