dataforge-io/src/commonTest/kotlin/space/kscience/dataforge/io/MetaFormatTest.kt

@@ -7,11 +7,11 @@ import kotlin.test.assertEquals
 
 
 fun Meta.toByteArray(format: MetaFormat = JsonMetaFormat) = ByteArray {
-    format.writeObject(this@ByteArray, this@toByteArray)
+    format.writeTo(this@ByteArray, this@toByteArray)
 }
 
 fun MetaFormat.fromByteArray(packet: ByteArray): Meta {
-    return packet.asBinary().read { readObject(this) }
+    return packet.asBinary().read { readFrom(this) }
 }
 
 class MetaFormatTest {

dataforge-io/src/commonTest/kotlin/space/kscience/dataforge/io/ioTestUtils.kt

@@ -4,8 +4,8 @@ import kotlinx.io.buffered
 
 
 fun <T : Any> IOFormat<T>.writeToByteArray(obj: T): ByteArray = ByteArray {
-    writeObject(this, obj)
+    writeTo(this, obj)
 }
 fun <T : Any> IOFormat<T>.readFromByteArray(array: ByteArray): T = ByteArraySource(array).buffered().use {
-    readObject(it)
+    readFrom(it)
 }

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

@@ -50,7 +50,9 @@ public interface Meta : MetaRepr, MetaProvider {
     override fun toMeta(): Meta = this
 
     override fun toString(): String
+
     override fun equals(other: Any?): Boolean
+
     override fun hashCode(): Int
 
     public companion object {

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

@@ -11,7 +11,7 @@ import kotlin.js.JsName
  * Mark a meta builder
  */
 @DslMarker
-public annotation class MetaBuilder
+public annotation class MetaBuilderMarker
 
 /**
  * A generic interface that gives access to getting and setting meta notes and values
@@ -27,7 +27,7 @@ public interface MutableMetaProvider : MetaProvider, MutableValueProvider {
  * TODO documentation
  */
 @Serializable(MutableMetaSerializer::class)
-@MetaBuilder
+@MetaBuilderMarker
 public interface MutableMeta : Meta, MutableMetaProvider {
 
     override val items: Map<NameToken, MutableMeta>
@@ -90,8 +90,8 @@ public interface MutableMeta : Meta, MutableMetaProvider {
         setMeta(this, repr.toMeta())
     }
 
-    public infix fun Name.put(mutableMeta: MutableMeta.() -> Unit) {
-        setMeta(this, Meta(mutableMeta))
+    public infix fun Name.put(builder: MutableMeta.() -> Unit) {
+        getOrCreate(this).apply(builder)
     }
 
     public infix fun String.put(meta: Meta) {
@@ -131,7 +131,7 @@ public interface MutableMeta : Meta, MutableMetaProvider {
     }
 
     public infix fun String.put(builder: MutableMeta.() -> Unit) {
-        setMeta(Name.parse(this), MutableMeta(builder))
+        getOrCreate(parseAsName()).apply(builder)
     }
 }
 
@@ -381,16 +381,14 @@ public fun Meta.toMutableMeta(): ObservableMutableMeta = MutableMetaImpl(value,
 
 public fun Meta.asMutableMeta(): MutableMeta = (this as? MutableMeta) ?: toMutableMeta()
 
-@Suppress("FunctionName")
-@JsName("newMutableMeta")
-public fun MutableMeta(): ObservableMutableMeta = MutableMetaImpl(null)
+@JsName("newObservableMutableMeta")
+public fun ObservableMutableMeta(): ObservableMutableMeta = MutableMetaImpl(null)
 
 /**
  * Build a [MutableMeta] using given transformation
  */
-@Suppress("FunctionName")
-public inline fun MutableMeta(builder: MutableMeta.() -> Unit = {}): ObservableMutableMeta =
-    MutableMeta().apply(builder)
+public inline fun ObservableMutableMeta(builder: MutableMeta.() -> Unit = {}): ObservableMutableMeta =
+    ObservableMutableMeta().apply(builder)
 
 
 /**

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

@@ -51,6 +51,8 @@ private class ObservableMetaWrapper(
 
     override fun setMeta(name: Name, node: Meta?) {
         val oldMeta = get(name)
+        //don't forget to remove listener
+        oldMeta?.removeListener(this)
         root.setMeta(absoluteName + name, node)
         if (oldMeta != node) {
             invalidate(name)

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

@@ -1,16 +1,17 @@
 package space.kscience.dataforge.meta
 
 import kotlinx.serialization.Serializable
-import space.kscience.dataforge.names.NameToken
+import space.kscience.dataforge.names.*
+import kotlin.js.JsName
 
 /**
  * The meta implementation which is guaranteed to be immutable.
  *
  */
 @Serializable
-public class SealedMeta internal constructor(
+public class SealedMeta(
     override val value: Value?,
-    override val items: Map<NameToken, SealedMeta>
+    override val items: Map<NameToken, SealedMeta>,
 ) : TypedMeta<SealedMeta> {
     override fun toString(): String = Meta.toString(this)
     override fun equals(other: Any?): Boolean = Meta.equals(this, other as? Meta)
@@ -26,7 +27,7 @@ public class SealedMeta internal constructor(
 }
 
 /**
- * Generate sealed node from [this]. If it is already sealed return it as is.
+ * Generate sealed node from [this]. If it is already sealed, return it as is.
  */
 public fun Meta.seal(): SealedMeta = this as? SealedMeta ?: SealedMeta(
     value,
@@ -47,7 +48,79 @@ public fun Meta(value: String): SealedMeta = Meta(value.asValue())
 @Suppress("FunctionName")
 public fun Meta(value: Boolean): SealedMeta = Meta(value.asValue())
 
-@Suppress("FunctionName")
-public inline fun Meta(builder: MutableMeta.() -> Unit): SealedMeta =
-    MutableMeta(builder).seal()
 
+/**
+ * A lightweight mutable meta used to create [SealedMeta] instances without bothering with
+ */
+@PublishedApi
+internal class MetaBuilder(
+    override var value: Value? = null,
+    override val items: MutableMap<NameToken, MetaBuilder> = hashMapOf(),
+) : MutableMeta {
+
+    override fun getOrCreate(name: Name): MetaBuilder {
+        val existing = get(name) as? MetaBuilder
+        return if (existing == null) {
+            val newItem = MetaBuilder()
+            setMeta(name, newItem)
+            newItem
+        } else {
+            existing
+        }
+    }
+
+    private fun wrap(meta: Meta): MetaBuilder = meta as? MetaBuilder ?: MetaBuilder(
+        meta.value,
+        meta.items.mapValuesTo(hashMapOf()) { wrap(it.value) }
+    )
+
+
+    override fun setMeta(name: Name, node: Meta?) {
+        when (name.length) {
+            0 -> error("Can't set a meta with empty name")
+            1 -> {
+                val token = name.first()
+                //remove child and invalidate if argument is null
+                if (node == null) {
+                    items.remove(token)
+                } else {
+                    items[token] = wrap(node)
+                }
+            }
+
+            else -> {
+                getOrCreate(name.first().asName()).setMeta(name.cutFirst(), node)
+            }
+        }
+    }
+
+    override fun toString(): String = Meta.toString(this)
+
+    override fun equals(other: Any?): Boolean = Meta.equals(this, other as? Meta)
+
+    override fun hashCode(): Int = Meta.hashCode(this)
+}
+
+/**
+ * Create a read-only meta.
+ */
+public inline fun Meta(builder: MutableMeta.() -> Unit): Meta =
+    MetaBuilder().apply(builder).seal()
+
+/**
+ * Create an immutable meta.
+ */
+public inline fun SealedMeta(builder: MutableMeta.() -> Unit): SealedMeta =
+    MetaBuilder().apply(builder).seal()
+
+/**
+ * Create an empty meta mutable meta.
+ */
+@JsName("newMutableMeta")
+public fun MutableMeta(): MutableMeta = MetaBuilder()
+
+/**
+ * Create a mutable meta with given builder.
+ */
+public inline fun MutableMeta(builder: MutableMeta.() -> Unit = {}): MutableMeta =
+    MutableMeta().apply(builder)

dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/transformations/MetaTransformation.kt

@@ -105,7 +105,7 @@ public value class MetaTransformation(private val transformations: Collection<Tr
      * Generate an observable configuration that contains only elements defined by transformation rules and changes with the source
      */
     @DFExperimental
-    public fun generate(source: ObservableMeta): ObservableMeta = MutableMeta().apply {
+    public fun generate(source: ObservableMeta): ObservableMeta = ObservableMutableMeta{
         transformations.forEach { rule ->
             rule.selectItems(source).forEach { name ->
                 rule.transformItem(name, source[name], this)

dataforge-meta/src/jvmTest/kotlin/space/kscience/dataforge/meta/JvmMutableMetaTest.kt

@@ -1,15 +0,0 @@
-package space.kscience.dataforge.meta
-
-import org.junit.jupiter.api.Test
-import kotlin.test.assertFails
-
-class JvmMutableMetaTest {
-    @Test
-    fun recursiveMeta(){
-        val meta = MutableMeta {
-            "a" put 2
-        }
-
-        assertFails { meta["child.a"] = meta }
-    }
-}