diff --git a/CHANGELOG.md b/CHANGELOG.md
index c7bf4dfd..dfa1206e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,8 @@
 - Scheme made observable
 - Global context is a variable (the singleton is hidden and will be deprecated in future)
 - Kotlin 1.5
+- Added blank builders for children context.
+- Refactor loggers
 
 ### Deprecated
 - Direct use of PluginManager
diff --git a/build.gradle.kts b/build.gradle.kts
index 9b8051e4..abe746a4 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -4,7 +4,7 @@ plugins {
 
 allprojects {
     group = "space.kscience"
-    version = "0.4.0-dev-8"
+    version = "0.4.0"
 }
 
 subprojects {
diff --git a/dataforge-context/api/dataforge-context.api b/dataforge-context/api/dataforge-context.api
index 8dfdab6e..3cf0970c 100644
--- a/dataforge-context/api/dataforge-context.api
+++ b/dataforge-context/api/dataforge-context.api
@@ -3,17 +3,12 @@ public abstract class space/kscience/dataforge/context/AbstractPlugin : space/ks
 	public fun <init> (Lspace/kscience/dataforge/meta/Meta;)V
 	public synthetic fun <init> (Lspace/kscience/dataforge/meta/Meta;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public fun attach (Lspace/kscience/dataforge/context/Context;)V
-	public fun content (Ljava/lang/String;)Ljava/util/Map;
 	public final fun dependsOn ()Ljava/util/Map;
 	public fun detach ()V
 	public fun getContext ()Lspace/kscience/dataforge/context/Context;
-	public fun getDefaultChainTarget ()Ljava/lang/String;
-	public fun getDefaultTarget ()Ljava/lang/String;
 	public fun getMeta ()Lspace/kscience/dataforge/meta/Meta;
-	public fun getName ()Lspace/kscience/dataforge/names/Name;
 	protected final fun require (Lspace/kscience/dataforge/context/PluginFactory;Lspace/kscience/dataforge/meta/Meta;)Lkotlin/properties/ReadOnlyProperty;
 	public static synthetic fun require$default (Lspace/kscience/dataforge/context/AbstractPlugin;Lspace/kscience/dataforge/context/PluginFactory;Lspace/kscience/dataforge/meta/Meta;ILjava/lang/Object;)Lkotlin/properties/ReadOnlyProperty;
-	public fun toMeta ()Lspace/kscience/dataforge/meta/Meta;
 }
 
 public final class space/kscience/dataforge/context/AbstractPluginKt {
@@ -44,7 +39,6 @@ public class space/kscience/dataforge/context/Context : kotlinx/coroutines/Corou
 	public fun content (Ljava/lang/String;)Ljava/util/Map;
 	public final fun content (Ljava/lang/String;Z)Ljava/util/Map;
 	public fun getCoroutineContext ()Lkotlin/coroutines/CoroutineContext;
-	public fun getDefaultChainTarget ()Ljava/lang/String;
 	public fun getDefaultTarget ()Ljava/lang/String;
 	public final fun getName ()Lspace/kscience/dataforge/names/Name;
 	public final fun getParent ()Lspace/kscience/dataforge/context/Context;
@@ -83,8 +77,9 @@ public final class space/kscience/dataforge/context/ContextBuilderKt {
 public final class space/kscience/dataforge/context/DefaultLogManager : space/kscience/dataforge/context/AbstractPlugin, space/kscience/dataforge/context/LogManager {
 	public static final field Companion Lspace/kscience/dataforge/context/DefaultLogManager$Companion;
 	public fun <init> ()V
+	public fun getDefaultLogger ()Lspace/kscience/dataforge/context/Logger;
 	public fun getTag ()Lspace/kscience/dataforge/context/PluginTag;
-	public fun log (Lspace/kscience/dataforge/names/Name;Ljava/lang/String;Lkotlin/jvm/functions/Function0;)V
+	public fun logger (Lspace/kscience/dataforge/names/Name;)Lspace/kscience/dataforge/context/Logger;
 }
 
 public final class space/kscience/dataforge/context/DefaultLogManager$Companion : space/kscience/dataforge/context/PluginFactory {
@@ -96,9 +91,6 @@ public final class space/kscience/dataforge/context/DefaultLogManager$Companion
 
 public abstract interface class space/kscience/dataforge/context/Factory {
 	public abstract fun invoke (Lspace/kscience/dataforge/meta/Meta;Lspace/kscience/dataforge/context/Context;)Ljava/lang/Object;
-}
-
-public final class space/kscience/dataforge/context/Factory$DefaultImpls {
 	public static synthetic fun invoke$default (Lspace/kscience/dataforge/context/Factory;Lspace/kscience/dataforge/meta/Meta;Lspace/kscience/dataforge/context/Context;ILjava/lang/Object;)Ljava/lang/Object;
 }
 
@@ -108,13 +100,17 @@ public final class space/kscience/dataforge/context/GlobalKt {
 	public static final fun getGlobal ()Lspace/kscience/dataforge/context/Context;
 }
 
-public abstract interface class space/kscience/dataforge/context/LogManager : space/kscience/dataforge/context/Logable, space/kscience/dataforge/context/Plugin {
+public abstract interface class space/kscience/dataforge/context/LogManager : space/kscience/dataforge/context/Logger, space/kscience/dataforge/context/Plugin {
 	public static final field Companion Lspace/kscience/dataforge/context/LogManager$Companion;
 	public static final field DEBUG Ljava/lang/String;
 	public static final field ERROR Ljava/lang/String;
 	public static final field INFO Ljava/lang/String;
 	public static final field TRACE Ljava/lang/String;
 	public static final field WARNING Ljava/lang/String;
+	public abstract fun getDefaultLogger ()Lspace/kscience/dataforge/context/Logger;
+	public fun log (Ljava/lang/String;Lkotlin/jvm/functions/Function0;)V
+	public fun log (Lspace/kscience/dataforge/names/Name;Ljava/lang/String;Lkotlin/jvm/functions/Function0;)V
+	public abstract fun logger (Lspace/kscience/dataforge/names/Name;)Lspace/kscience/dataforge/context/Logger;
 }
 
 public final class space/kscience/dataforge/context/LogManager$Companion {
@@ -125,33 +121,19 @@ public final class space/kscience/dataforge/context/LogManager$Companion {
 	public static final field WARNING Ljava/lang/String;
 }
 
-public final class space/kscience/dataforge/context/LogManager$DefaultImpls {
-	public static fun content (Lspace/kscience/dataforge/context/LogManager;Ljava/lang/String;)Ljava/util/Map;
-	public static fun getDefaultChainTarget (Lspace/kscience/dataforge/context/LogManager;)Ljava/lang/String;
-	public static fun getDefaultTarget (Lspace/kscience/dataforge/context/LogManager;)Ljava/lang/String;
-	public static fun getName (Lspace/kscience/dataforge/context/LogManager;)Lspace/kscience/dataforge/names/Name;
-	public static fun toMeta (Lspace/kscience/dataforge/context/LogManager;)Lspace/kscience/dataforge/meta/Meta;
-}
-
 public final class space/kscience/dataforge/context/LogManagerKt {
-	public static final fun debug (Lspace/kscience/dataforge/context/Logable;Lspace/kscience/dataforge/names/Name;Lkotlin/jvm/functions/Function0;)V
-	public static synthetic fun debug$default (Lspace/kscience/dataforge/context/Logable;Lspace/kscience/dataforge/names/Name;Lkotlin/jvm/functions/Function0;ILjava/lang/Object;)V
-	public static final fun error (Lspace/kscience/dataforge/context/Logable;Ljava/lang/Throwable;Lspace/kscience/dataforge/names/Name;Lkotlin/jvm/functions/Function0;)V
-	public static final fun error (Lspace/kscience/dataforge/context/Logable;Lspace/kscience/dataforge/names/Name;Lkotlin/jvm/functions/Function0;)V
-	public static synthetic fun error$default (Lspace/kscience/dataforge/context/Logable;Ljava/lang/Throwable;Lspace/kscience/dataforge/names/Name;Lkotlin/jvm/functions/Function0;ILjava/lang/Object;)V
-	public static synthetic fun error$default (Lspace/kscience/dataforge/context/Logable;Lspace/kscience/dataforge/names/Name;Lkotlin/jvm/functions/Function0;ILjava/lang/Object;)V
-	public static final fun getLogger (Lspace/kscience/dataforge/context/Context;)Lspace/kscience/dataforge/context/Logable;
-	public static final fun getLogger (Lspace/kscience/dataforge/context/ContextAware;)Lspace/kscience/dataforge/context/Logable;
-	public static final fun info (Lspace/kscience/dataforge/context/Logable;Lspace/kscience/dataforge/names/Name;Lkotlin/jvm/functions/Function0;)V
-	public static synthetic fun info$default (Lspace/kscience/dataforge/context/Logable;Lspace/kscience/dataforge/names/Name;Lkotlin/jvm/functions/Function0;ILjava/lang/Object;)V
-	public static final fun trace (Lspace/kscience/dataforge/context/Logable;Lspace/kscience/dataforge/names/Name;Lkotlin/jvm/functions/Function0;)V
-	public static synthetic fun trace$default (Lspace/kscience/dataforge/context/Logable;Lspace/kscience/dataforge/names/Name;Lkotlin/jvm/functions/Function0;ILjava/lang/Object;)V
-	public static final fun warn (Lspace/kscience/dataforge/context/Logable;Lspace/kscience/dataforge/names/Name;Lkotlin/jvm/functions/Function0;)V
-	public static synthetic fun warn$default (Lspace/kscience/dataforge/context/Logable;Lspace/kscience/dataforge/names/Name;Lkotlin/jvm/functions/Function0;ILjava/lang/Object;)V
+	public static final fun debug (Lspace/kscience/dataforge/context/Logger;Lkotlin/jvm/functions/Function0;)V
+	public static final fun error (Lspace/kscience/dataforge/context/Logger;Ljava/lang/Throwable;Lkotlin/jvm/functions/Function0;)V
+	public static final fun error (Lspace/kscience/dataforge/context/Logger;Lkotlin/jvm/functions/Function0;)V
+	public static final fun getLogger (Lspace/kscience/dataforge/context/Context;)Lspace/kscience/dataforge/context/LogManager;
+	public static final fun getLogger (Lspace/kscience/dataforge/context/ContextAware;)Lspace/kscience/dataforge/context/Logger;
+	public static final fun info (Lspace/kscience/dataforge/context/Logger;Lkotlin/jvm/functions/Function0;)V
+	public static final fun trace (Lspace/kscience/dataforge/context/Logger;Lkotlin/jvm/functions/Function0;)V
+	public static final fun warn (Lspace/kscience/dataforge/context/Logger;Lkotlin/jvm/functions/Function0;)V
 }
 
-public abstract interface class space/kscience/dataforge/context/Logable {
-	public abstract fun log (Lspace/kscience/dataforge/names/Name;Ljava/lang/String;Lkotlin/jvm/functions/Function0;)V
+public abstract interface class space/kscience/dataforge/context/Logger {
+	public abstract fun log (Ljava/lang/String;Lkotlin/jvm/functions/Function0;)V
 }
 
 public abstract interface class space/kscience/dataforge/context/Plugin : space/kscience/dataforge/context/ContextAware, space/kscience/dataforge/meta/MetaRepr, space/kscience/dataforge/misc/Named, space/kscience/dataforge/provider/Provider {
@@ -161,23 +143,15 @@ public abstract interface class space/kscience/dataforge/context/Plugin : space/
 	public abstract fun dependsOn ()Ljava/util/Map;
 	public abstract fun detach ()V
 	public abstract fun getMeta ()Lspace/kscience/dataforge/meta/Meta;
-	public abstract fun getName ()Lspace/kscience/dataforge/names/Name;
+	public fun getName ()Lspace/kscience/dataforge/names/Name;
 	public abstract fun getTag ()Lspace/kscience/dataforge/context/PluginTag;
-	public abstract fun toMeta ()Lspace/kscience/dataforge/meta/Meta;
+	public fun toMeta ()Lspace/kscience/dataforge/meta/Meta;
 }
 
 public final class space/kscience/dataforge/context/Plugin$Companion {
 	public static final field TARGET Ljava/lang/String;
 }
 
-public final class space/kscience/dataforge/context/Plugin$DefaultImpls {
-	public static fun content (Lspace/kscience/dataforge/context/Plugin;Ljava/lang/String;)Ljava/util/Map;
-	public static fun getDefaultChainTarget (Lspace/kscience/dataforge/context/Plugin;)Ljava/lang/String;
-	public static fun getDefaultTarget (Lspace/kscience/dataforge/context/Plugin;)Ljava/lang/String;
-	public static fun getName (Lspace/kscience/dataforge/context/Plugin;)Lspace/kscience/dataforge/names/Name;
-	public static fun toMeta (Lspace/kscience/dataforge/context/Plugin;)Lspace/kscience/dataforge/meta/Meta;
-}
-
 public abstract interface class space/kscience/dataforge/context/PluginFactory : space/kscience/dataforge/context/Factory {
 	public static final field Companion Lspace/kscience/dataforge/context/PluginFactory$Companion;
 	public static final field TYPE Ljava/lang/String;
@@ -242,8 +216,9 @@ public final class space/kscience/dataforge/context/ResolveKt {
 public final class space/kscience/dataforge/context/SlfLogManager : space/kscience/dataforge/context/AbstractPlugin, space/kscience/dataforge/context/LogManager {
 	public static final field Companion Lspace/kscience/dataforge/context/SlfLogManager$Companion;
 	public fun <init> ()V
+	public fun getDefaultLogger ()Lspace/kscience/dataforge/context/Logger;
 	public fun getTag ()Lspace/kscience/dataforge/context/PluginTag;
-	public fun log (Lspace/kscience/dataforge/names/Name;Ljava/lang/String;Lkotlin/jvm/functions/Function0;)V
+	public fun logger (Lspace/kscience/dataforge/names/Name;)Lspace/kscience/dataforge/context/Logger;
 }
 
 public final class space/kscience/dataforge/context/SlfLogManager$Companion : space/kscience/dataforge/context/PluginFactory {
@@ -275,11 +250,6 @@ public abstract interface annotation class space/kscience/dataforge/descriptors/
 	public abstract fun type ()[Lspace/kscience/dataforge/values/ValueType;
 }
 
-public final class space/kscience/dataforge/properties/Property$DefaultImpls {
-	public static synthetic fun onChange$default (Lspace/kscience/dataforge/properties/Property;Ljava/lang/Object;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)V
-	public static synthetic fun removeChangeListener$default (Lspace/kscience/dataforge/properties/Property;Ljava/lang/Object;ILjava/lang/Object;)V
-}
-
 public final class space/kscience/dataforge/properties/PropertyKt {
 }
 
@@ -345,15 +315,9 @@ public final class space/kscience/dataforge/provider/PathToken$Companion {
 }
 
 public abstract interface class space/kscience/dataforge/provider/Provider {
-	public abstract fun content (Ljava/lang/String;)Ljava/util/Map;
-	public abstract fun getDefaultChainTarget ()Ljava/lang/String;
-	public abstract fun getDefaultTarget ()Ljava/lang/String;
-}
-
-public final class space/kscience/dataforge/provider/Provider$DefaultImpls {
-	public static fun content (Lspace/kscience/dataforge/provider/Provider;Ljava/lang/String;)Ljava/util/Map;
-	public static fun getDefaultChainTarget (Lspace/kscience/dataforge/provider/Provider;)Ljava/lang/String;
-	public static fun getDefaultTarget (Lspace/kscience/dataforge/provider/Provider;)Ljava/lang/String;
+	public fun content (Ljava/lang/String;)Ljava/util/Map;
+	public fun getDefaultChainTarget ()Ljava/lang/String;
+	public fun getDefaultTarget ()Ljava/lang/String;
 }
 
 public final class space/kscience/dataforge/provider/ProviderKt {
diff --git a/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/Context.kt b/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/Context.kt
index 74bb062f..2451048d 100644
--- a/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/Context.kt
+++ b/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/Context.kt
@@ -76,7 +76,7 @@ public open class Context internal constructor(
      * Build and register a child context
      */
     @Synchronized
-    public fun buildContext(name: String? = null, block: ContextBuilder.() -> Unit): Context {
+    public fun buildContext(name: String? = null, block: ContextBuilder.() -> Unit = {}): Context {
         val newContext = ContextBuilder(this)
             .apply { name?.let { name(it) } }
             .apply(block)
diff --git a/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/LogManager.kt b/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/LogManager.kt
index 10f9c7af..d3efed6f 100644
--- a/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/LogManager.kt
+++ b/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/LogManager.kt
@@ -6,11 +6,19 @@ import space.kscience.dataforge.names.Name
 import space.kscience.dataforge.names.plus
 import kotlin.reflect.KClass
 
-public fun interface Logable {
-    public fun log(name: Name, tag: String, body: () -> String)
+public fun interface Logger {
+    public fun log(tag: String, body: () -> String)
 }
 
-public interface LogManager : Plugin, Logable {
+public interface LogManager : Plugin, Logger {
+    public fun logger(name: Name): Logger
+
+    public val defaultLogger: Logger
+
+    override fun log(tag: String, body: () -> String): Unit = defaultLogger.log(tag, body)
+
+    public fun log(name: Name, tag: String, body: () -> String): Unit = logger(name).log(tag, body)
+
     public companion object {
         public const val TRACE: String = "TRACE"
         public const val INFO: String = "INFO"
@@ -20,11 +28,11 @@ public interface LogManager : Plugin, Logable {
     }
 }
 
-public fun Logable.trace(name: Name = Name.EMPTY, body: () -> String): Unit = log(name, LogManager.TRACE, body)
-public fun Logable.info(name: Name = Name.EMPTY, body: () -> String): Unit = log(name, LogManager.INFO, body)
-public fun Logable.debug(name: Name = Name.EMPTY, body: () -> String): Unit = log(name, LogManager.DEBUG, body)
-public fun Logable.warn(name: Name = Name.EMPTY, body: () -> String): Unit = log(name, LogManager.WARNING, body)
-public fun Logable.error(name: Name = Name.EMPTY, body: () -> String): Unit = log(name, LogManager.ERROR, body)
+public fun Logger.trace(body: () -> String): Unit = log(LogManager.TRACE, body)
+public fun Logger.info(body: () -> String): Unit = log(LogManager.INFO, body)
+public fun Logger.debug(body: () -> String): Unit = log(LogManager.DEBUG, body)
+public fun Logger.warn(body: () -> String): Unit = log(LogManager.WARNING, body)
+public fun Logger.error(body: () -> String): Unit = log(LogManager.ERROR, body)
 
 internal val (() -> String).safe: String
     get() = try {
@@ -34,22 +42,24 @@ internal val (() -> String).safe: String
     }
 
 
-public fun Logable.error(throwable: Throwable?, name: Name = Name.EMPTY, body: () -> String): Unit =
-    log(name, LogManager.ERROR) {
-        buildString {
-            appendLine(body())
-            throwable?.let { appendLine(throwable.stackTraceToString()) }
-        }
+public fun Logger.error(throwable: Throwable?, body: () -> String): Unit = log(LogManager.ERROR) {
+    buildString {
+        appendLine(body())
+        throwable?.let { appendLine(throwable.stackTraceToString()) }
     }
+}
 
 
 public class DefaultLogManager : AbstractPlugin(), LogManager {
 
-    override fun log(name: Name, tag: String, body: () -> String) {
+    override fun logger(name: Name): Logger = Logger { tag, body ->
         val message: String = body.safe
-        println("[${context.name}] $name: $message")
+        println("$tag $name: [${context.name}] $message")
     }
 
+    override val defaultLogger: Logger = logger(Name.EMPTY)
+
+
     override val tag: PluginTag get() = Companion.tag
 
     public companion object : PluginFactory<DefaultLogManager> {
@@ -63,20 +73,17 @@ public class DefaultLogManager : AbstractPlugin(), LogManager {
 /**
  * Context log manager inherited from parent
  */
-public val Context.logger: Logable
+public val Context.logger: LogManager
     get() = plugins.find(inherit = true) { it is LogManager } as? LogManager
         ?: globalLoggerFactory(context = Global).apply { attach(Global) }
 
 /**
  * The named proxy logger for a context member
  */
-public val ContextAware.logger: Logable
+public val ContextAware.logger: Logger
     get() = if (this is Named) {
-        object : Logable {
-            val contextLog = context.logger
-            override fun log(name: Name, tag: String, body: () -> String) {
-                contextLog.log(this@logger.name + name, tag, body)
-            }
+        Logger { tag, body ->
+            context.logger.log(this@logger.name + name, tag, body)
         }
     } else {
         context.logger
diff --git a/dataforge-context/src/jsMain/kotlin/space/kscience/dataforge/context/loggingJs.kt b/dataforge-context/src/jsMain/kotlin/space/kscience/dataforge/context/loggingJs.kt
index 3c822b82..406929ca 100644
--- a/dataforge-context/src/jsMain/kotlin/space/kscience/dataforge/context/loggingJs.kt
+++ b/dataforge-context/src/jsMain/kotlin/space/kscience/dataforge/context/loggingJs.kt
@@ -6,7 +6,7 @@ import kotlin.reflect.KClass
 
 public class ConsoleLogManager : AbstractPlugin(), LogManager {
 
-    override fun log(name: Name, tag: String, body: () -> String) {
+    override fun logger(name: Name): Logger  = Logger { tag, body ->
         val message: String = body.safe
         when (tag) {
             LogManager.INFO -> console.info("[${context.name}] $name: $message")
@@ -16,6 +16,9 @@ public class ConsoleLogManager : AbstractPlugin(), LogManager {
         }
     }
 
+    override val defaultLogger: Logger = logger(Name.EMPTY)
+
+
     override val tag: PluginTag get() = Companion.tag
 
     public companion object : PluginFactory<ConsoleLogManager> {
diff --git a/dataforge-context/src/jvmMain/kotlin/space/kscience/dataforge/context/loggingJvm.kt b/dataforge-context/src/jvmMain/kotlin/space/kscience/dataforge/context/loggingJvm.kt
index 9fa9226c..05763e00 100644
--- a/dataforge-context/src/jvmMain/kotlin/space/kscience/dataforge/context/loggingJvm.kt
+++ b/dataforge-context/src/jvmMain/kotlin/space/kscience/dataforge/context/loggingJvm.kt
@@ -7,7 +7,7 @@ import kotlin.reflect.KClass
 
 public class SlfLogManager : AbstractPlugin(), LogManager {
 
-    override fun log(name: Name, tag: String, body: () -> String) {
+    override fun logger(name: Name): Logger = Logger { tag, body ->
         val logger = LoggerFactory.getLogger("[${context.name}] $name") //KotlinLogging.logger("[${context.name}] $name")
         val message = body.safe
         when (tag) {
@@ -19,6 +19,8 @@ public class SlfLogManager : AbstractPlugin(), LogManager {
         }
     }
 
+    override val defaultLogger: Logger = logger(Name.EMPTY)
+
     override val tag: PluginTag get() = Companion.tag
 
     public companion object : PluginFactory<SlfLogManager> {
diff --git a/dataforge-data/src/commonMain/kotlin/space/kscience/dataforge/data/CoroutineMonitor.kt b/dataforge-data/src/commonMain/kotlin/space/kscience/dataforge/data/CoroutineMonitor.kt
index c8c1a78f..4607d92c 100644
--- a/dataforge-data/src/commonMain/kotlin/space/kscience/dataforge/data/CoroutineMonitor.kt
+++ b/dataforge-data/src/commonMain/kotlin/space/kscience/dataforge/data/CoroutineMonitor.kt
@@ -48,9 +48,9 @@ public val CoroutineScope.monitor: CoroutineMonitor? get() = coroutineContext.mo
 public val Job.dependencies: Collection<Job> get() = this[Dependencies]?.values ?: emptyList()
 
 @DFExperimental
-public val Job.totalWork: Double get() = dependencies.sumByDouble { totalWork } + (monitor?.totalWork ?: 0.0)
+public val Job.totalWork: Double get() = dependencies.sumOf { totalWork } + (monitor?.totalWork ?: 0.0)
 @DFExperimental
-public val Job.workDone: Double get() = dependencies.sumByDouble { workDone } + (monitor?.workDone ?: 0.0)
+public val Job.workDone: Double get() = dependencies.sumOf { workDone } + (monitor?.workDone ?: 0.0)
 @DFExperimental
 public val Job.status: String get() = monitor?.status ?: ""
 @DFExperimental
diff --git a/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/BinaryMetaFormat.kt b/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/BinaryMetaFormat.kt
index 96ac4522..38ca6ec2 100644
--- a/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/BinaryMetaFormat.kt
+++ b/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/BinaryMetaFormat.kt
@@ -20,7 +20,7 @@ public object BinaryMetaFormat : MetaFormat, MetaFormatFactory {
         return (input.readMetaItem() as MetaItemNode).node
     }
 
-    private fun Output.writeChar(char: Char) = writeByte(char.toByte())
+    private fun Output.writeChar(char: Char) = writeByte(char.code.toByte())
 
     private fun Output.writeString(str: String) {
         writeInt(str.length)
@@ -101,7 +101,7 @@ public object BinaryMetaFormat : MetaFormat, MetaFormatFactory {
 
     @Suppress("UNCHECKED_CAST")
     public fun Input.readMetaItem(): TypedMetaItem<MetaBuilder> {
-        return when (val keyChar = readByte().toChar()) {
+        return when (val keyChar = readByte().toInt().toChar()) {
             'S' -> MetaItemValue(StringValue(readString()))
             'N' -> MetaItemValue(Null)
             '+' -> MetaItemValue(True)
diff --git a/dataforge-meta/api/dataforge-meta.api b/dataforge-meta/api/dataforge-meta.api
index 47b38de5..e3572ca2 100644
--- a/dataforge-meta/api/dataforge-meta.api
+++ b/dataforge-meta/api/dataforge-meta.api
@@ -9,7 +9,6 @@ public abstract class space/kscience/dataforge/meta/AbstractMutableMeta : space/
 
 public abstract class space/kscience/dataforge/meta/AbstractTypedMeta : space/kscience/dataforge/meta/MetaBase, space/kscience/dataforge/meta/TypedMeta {
 	public fun <init> ()V
-	public fun getItem (Lspace/kscience/dataforge/names/Name;)Lspace/kscience/dataforge/meta/TypedMetaItem;
 }
 
 public final class space/kscience/dataforge/meta/Config : space/kscience/dataforge/meta/AbstractMutableMeta, space/kscience/dataforge/meta/ItemPropertyProvider {
@@ -33,6 +32,8 @@ public final class space/kscience/dataforge/meta/Config$ConfigSerializer : kotli
 
 public final class space/kscience/dataforge/meta/ConfigKt {
 	public static final fun asConfig (Lspace/kscience/dataforge/meta/Meta;)Lspace/kscience/dataforge/meta/Config;
+	public static final fun copy (Lspace/kscience/dataforge/meta/Config;Lkotlin/jvm/functions/Function1;)Lspace/kscience/dataforge/meta/Config;
+	public static synthetic fun copy$default (Lspace/kscience/dataforge/meta/Config;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lspace/kscience/dataforge/meta/Config;
 	public static final fun get (Lspace/kscience/dataforge/meta/Config;Lspace/kscience/dataforge/names/NameToken;)Lspace/kscience/dataforge/meta/TypedMetaItem;
 	public static final fun toConfig (Lspace/kscience/dataforge/meta/Meta;)Lspace/kscience/dataforge/meta/Config;
 }
@@ -172,10 +173,10 @@ public abstract interface class space/kscience/dataforge/meta/Meta : space/kscie
 	public static final field TYPE Ljava/lang/String;
 	public static final field VALUE_KEY Ljava/lang/String;
 	public abstract fun equals (Ljava/lang/Object;)Z
-	public abstract fun getItem (Lspace/kscience/dataforge/names/Name;)Lspace/kscience/dataforge/meta/TypedMetaItem;
+	public fun getItem (Lspace/kscience/dataforge/names/Name;)Lspace/kscience/dataforge/meta/TypedMetaItem;
 	public abstract fun getItems ()Ljava/util/Map;
 	public abstract fun hashCode ()I
-	public abstract fun toMeta ()Lspace/kscience/dataforge/meta/Meta;
+	public fun toMeta ()Lspace/kscience/dataforge/meta/Meta;
 	public abstract fun toString ()Ljava/lang/String;
 }
 
@@ -186,17 +187,10 @@ public final class space/kscience/dataforge/meta/Meta$Companion {
 	public final fun getEMPTY ()Lspace/kscience/dataforge/meta/Meta;
 }
 
-public final class space/kscience/dataforge/meta/Meta$DefaultImpls {
-	public static fun getItem (Lspace/kscience/dataforge/meta/Meta;Lspace/kscience/dataforge/names/Name;)Lspace/kscience/dataforge/meta/TypedMetaItem;
-	public static fun toMeta (Lspace/kscience/dataforge/meta/Meta;)Lspace/kscience/dataforge/meta/Meta;
-}
-
 public abstract class space/kscience/dataforge/meta/MetaBase : space/kscience/dataforge/meta/Meta {
 	public fun <init> ()V
 	public fun equals (Ljava/lang/Object;)Z
-	public fun getItem (Lspace/kscience/dataforge/names/Name;)Lspace/kscience/dataforge/meta/TypedMetaItem;
 	public fun hashCode ()I
-	public fun toMeta ()Lspace/kscience/dataforge/meta/Meta;
 	public fun toString ()Ljava/lang/String;
 }
 
@@ -398,11 +392,6 @@ public abstract interface class space/kscience/dataforge/meta/MutableMeta : spac
 	public abstract fun getItems ()Ljava/util/Map;
 }
 
-public final class space/kscience/dataforge/meta/MutableMeta$DefaultImpls {
-	public static fun getItem (Lspace/kscience/dataforge/meta/MutableMeta;Lspace/kscience/dataforge/names/Name;)Lspace/kscience/dataforge/meta/TypedMetaItem;
-	public static fun toMeta (Lspace/kscience/dataforge/meta/MutableMeta;)Lspace/kscience/dataforge/meta/Meta;
-}
-
 public final class space/kscience/dataforge/meta/MutableMetaKt {
 	public static final fun append (Lspace/kscience/dataforge/meta/MutableItemProvider;Ljava/lang/String;Ljava/lang/Object;)V
 	public static final fun append (Lspace/kscience/dataforge/meta/MutableItemProvider;Lspace/kscience/dataforge/names/Name;Ljava/lang/Object;)V
@@ -419,14 +408,10 @@ public final class space/kscience/dataforge/meta/ObservableItemProviderKt {
 
 public abstract interface class space/kscience/dataforge/meta/ReadOnlySpecification {
 	public abstract fun empty ()Lspace/kscience/dataforge/meta/ItemProvider;
-	public abstract fun invoke (Lkotlin/jvm/functions/Function1;)Lspace/kscience/dataforge/meta/ItemProvider;
+	public fun invoke (Lkotlin/jvm/functions/Function1;)Lspace/kscience/dataforge/meta/ItemProvider;
 	public abstract fun read (Lspace/kscience/dataforge/meta/ItemProvider;)Lspace/kscience/dataforge/meta/ItemProvider;
 }
 
-public final class space/kscience/dataforge/meta/ReadOnlySpecification$DefaultImpls {
-	public static fun invoke (Lspace/kscience/dataforge/meta/ReadOnlySpecification;Lkotlin/jvm/functions/Function1;)Lspace/kscience/dataforge/meta/ItemProvider;
-}
-
 public class space/kscience/dataforge/meta/Scheme : space/kscience/dataforge/meta/ItemPropertyProvider, space/kscience/dataforge/meta/MetaRepr, space/kscience/dataforge/meta/descriptors/Described {
 	public fun <init> ()V
 	public fun getDefaultLayer ()Lspace/kscience/dataforge/meta/Meta;
@@ -475,10 +460,6 @@ public final class space/kscience/dataforge/meta/SealedMetaKt {
 
 public abstract interface class space/kscience/dataforge/meta/Specification : space/kscience/dataforge/meta/ReadOnlySpecification {
 	public abstract fun write (Lspace/kscience/dataforge/meta/MutableItemProvider;Lspace/kscience/dataforge/meta/ItemProvider;)Lspace/kscience/dataforge/meta/MutableItemProvider;
-}
-
-public final class space/kscience/dataforge/meta/Specification$DefaultImpls {
-	public static fun invoke (Lspace/kscience/dataforge/meta/Specification;Lkotlin/jvm/functions/Function1;)Lspace/kscience/dataforge/meta/MutableItemProvider;
 	public static synthetic fun write$default (Lspace/kscience/dataforge/meta/Specification;Lspace/kscience/dataforge/meta/MutableItemProvider;Lspace/kscience/dataforge/meta/ItemProvider;ILjava/lang/Object;)Lspace/kscience/dataforge/meta/MutableItemProvider;
 }
 
@@ -491,15 +472,10 @@ public final class space/kscience/dataforge/meta/SpecificationKt {
 }
 
 public abstract interface class space/kscience/dataforge/meta/TypedMeta : space/kscience/dataforge/meta/Meta {
-	public abstract fun getItem (Lspace/kscience/dataforge/names/Name;)Lspace/kscience/dataforge/meta/TypedMetaItem;
+	public fun getItem (Lspace/kscience/dataforge/names/Name;)Lspace/kscience/dataforge/meta/TypedMetaItem;
 	public abstract fun getItems ()Ljava/util/Map;
 }
 
-public final class space/kscience/dataforge/meta/TypedMeta$DefaultImpls {
-	public static fun getItem (Lspace/kscience/dataforge/meta/TypedMeta;Lspace/kscience/dataforge/names/Name;)Lspace/kscience/dataforge/meta/TypedMetaItem;
-	public static fun toMeta (Lspace/kscience/dataforge/meta/TypedMeta;)Lspace/kscience/dataforge/meta/Meta;
-}
-
 public abstract class space/kscience/dataforge/meta/TypedMetaItem {
 	public static final field Companion Lspace/kscience/dataforge/meta/TypedMetaItem$Companion;
 	public abstract fun equals (Ljava/lang/Object;)Z
@@ -530,78 +506,117 @@ public final class space/kscience/dataforge/meta/descriptors/DescriptorMetaKt {
 	public static final fun defaultMeta (Lspace/kscience/dataforge/meta/descriptors/NodeDescriptor;)Lspace/kscience/dataforge/meta/Laminate;
 }
 
-public abstract class space/kscience/dataforge/meta/descriptors/ItemDescriptor : space/kscience/dataforge/meta/Configurable {
+public abstract interface class space/kscience/dataforge/meta/descriptors/ItemDescriptor : space/kscience/dataforge/meta/MetaRepr {
 	public static final field Companion Lspace/kscience/dataforge/meta/descriptors/ItemDescriptor$Companion;
 	public static final field DEFAULT_INDEX_KEY Ljava/lang/String;
-	public synthetic fun <init> (Lspace/kscience/dataforge/meta/Config;Lkotlin/jvm/internal/DefaultConstructorMarker;)V
-	public abstract fun copy ()Lspace/kscience/dataforge/meta/descriptors/ItemDescriptor;
-	public final fun getAttributes ()Lspace/kscience/dataforge/meta/Config;
-	public final fun getConfig ()Lspace/kscience/dataforge/meta/Config;
-	public final fun getIndexKey ()Ljava/lang/String;
-	public final fun getInfo ()Ljava/lang/String;
-	public final fun getMultiple ()Z
+	public abstract fun getAttributes ()Lspace/kscience/dataforge/meta/Meta;
+	public abstract fun getIndexKey ()Ljava/lang/String;
+	public abstract fun getInfo ()Ljava/lang/String;
+	public abstract fun getMultiple ()Z
 	public abstract fun getRequired ()Z
-	public final fun setAttributes (Lspace/kscience/dataforge/meta/Config;)V
-	public final fun setIndexKey (Ljava/lang/String;)V
-	public final fun setInfo (Ljava/lang/String;)V
-	public final fun setMultiple (Z)V
-	public abstract fun setRequired (Z)V
 }
 
 public final class space/kscience/dataforge/meta/descriptors/ItemDescriptor$Companion {
+	public static final field DEFAULT_INDEX_KEY Ljava/lang/String;
+}
+
+public abstract class space/kscience/dataforge/meta/descriptors/ItemDescriptorBuilder : space/kscience/dataforge/meta/Configurable, space/kscience/dataforge/meta/descriptors/ItemDescriptor {
+	public static final field Companion Lspace/kscience/dataforge/meta/descriptors/ItemDescriptorBuilder$Companion;
+	public static final field DEFAULT_INDEX_KEY Ljava/lang/String;
+	public synthetic fun <init> (Lspace/kscience/dataforge/meta/Config;Lkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public abstract fun build ()Lspace/kscience/dataforge/meta/descriptors/ItemDescriptor;
+	public fun getAttributes ()Lspace/kscience/dataforge/meta/Config;
+	public synthetic fun getAttributes ()Lspace/kscience/dataforge/meta/Meta;
+	public final fun getConfig ()Lspace/kscience/dataforge/meta/Config;
+	public fun getIndexKey ()Ljava/lang/String;
+	public fun getInfo ()Ljava/lang/String;
+	public fun getMultiple ()Z
+	public abstract fun getRequired ()Z
+	public fun setAttributes (Lspace/kscience/dataforge/meta/Config;)V
+	public fun setIndexKey (Ljava/lang/String;)V
+	public fun setInfo (Ljava/lang/String;)V
+	public fun setMultiple (Z)V
+	public abstract fun setRequired (Z)V
+	public fun toMeta ()Lspace/kscience/dataforge/meta/Meta;
+}
+
+public final class space/kscience/dataforge/meta/descriptors/ItemDescriptorBuilder$Companion {
 }
 
 public final class space/kscience/dataforge/meta/descriptors/ItemDescriptorKt {
-	public static final fun NodeDescriptor (Lkotlin/jvm/functions/Function1;)Lspace/kscience/dataforge/meta/descriptors/NodeDescriptor;
-	public static final fun attributes (Lspace/kscience/dataforge/meta/descriptors/ItemDescriptor;Lkotlin/jvm/functions/Function1;)V
+	public static final fun attributes (Lspace/kscience/dataforge/meta/descriptors/ItemDescriptorBuilder;Lkotlin/jvm/functions/Function1;)V
 	public static final fun get (Lspace/kscience/dataforge/meta/descriptors/ItemDescriptor;Ljava/lang/String;)Lspace/kscience/dataforge/meta/descriptors/ItemDescriptor;
 	public static final fun get (Lspace/kscience/dataforge/meta/descriptors/ItemDescriptor;Lspace/kscience/dataforge/names/Name;)Lspace/kscience/dataforge/meta/descriptors/ItemDescriptor;
-	public static final fun plus (Lspace/kscience/dataforge/meta/descriptors/NodeDescriptor;Lspace/kscience/dataforge/meta/descriptors/NodeDescriptor;)Lspace/kscience/dataforge/meta/descriptors/NodeDescriptor;
 	public static final fun validateItem (Lspace/kscience/dataforge/meta/descriptors/ItemDescriptor;Lspace/kscience/dataforge/meta/TypedMetaItem;)Z
 }
 
-public final class space/kscience/dataforge/meta/descriptors/NodeDescriptor : space/kscience/dataforge/meta/descriptors/ItemDescriptor {
+public abstract interface class space/kscience/dataforge/meta/descriptors/NodeDescriptor : space/kscience/dataforge/meta/descriptors/ItemDescriptor {
 	public static final field Companion Lspace/kscience/dataforge/meta/descriptors/NodeDescriptor$Companion;
-	public fun <init> ()V
-	public fun <init> (Lspace/kscience/dataforge/meta/Config;)V
-	public synthetic fun <init> (Lspace/kscience/dataforge/meta/Config;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
-	public synthetic fun copy ()Lspace/kscience/dataforge/meta/descriptors/ItemDescriptor;
-	public fun copy ()Lspace/kscience/dataforge/meta/descriptors/NodeDescriptor;
-	public final fun getDefault ()Lspace/kscience/dataforge/meta/Config;
-	public final fun getItems ()Ljava/util/Map;
-	public final fun getNodes ()Ljava/util/Map;
-	public fun getRequired ()Z
-	public final fun getValues ()Ljava/util/Map;
-	public final fun item (Ljava/lang/String;Lspace/kscience/dataforge/meta/descriptors/ItemDescriptor;)V
-	public final fun item (Lspace/kscience/dataforge/names/Name;Lspace/kscience/dataforge/meta/descriptors/ItemDescriptor;)V
-	public final fun node (Ljava/lang/String;Lkotlin/jvm/functions/Function1;)V
-	public final fun node (Lspace/kscience/dataforge/names/Name;Lkotlin/jvm/functions/Function1;)V
-	public final fun setDefault (Lspace/kscience/dataforge/meta/Config;)V
-	public fun setRequired (Z)V
-	public final fun value (Ljava/lang/String;Lkotlin/jvm/functions/Function1;)V
-	public final fun value (Lspace/kscience/dataforge/names/Name;Lkotlin/jvm/functions/Function1;)V
+	public abstract fun getDefault ()Lspace/kscience/dataforge/meta/Config;
+	public abstract fun getItems ()Ljava/util/Map;
+	public abstract fun getNodes ()Ljava/util/Map;
+	public abstract fun getRequired ()Z
+	public abstract fun getValues ()Ljava/util/Map;
 }
 
 public final class space/kscience/dataforge/meta/descriptors/NodeDescriptor$Companion {
 }
 
-public final class space/kscience/dataforge/meta/descriptors/ValueDescriptor : space/kscience/dataforge/meta/descriptors/ItemDescriptor {
+public final class space/kscience/dataforge/meta/descriptors/NodeDescriptorBuilder : space/kscience/dataforge/meta/descriptors/ItemDescriptorBuilder, space/kscience/dataforge/meta/descriptors/NodeDescriptor {
+	public static final field Companion Lspace/kscience/dataforge/meta/descriptors/NodeDescriptorBuilder$Companion;
+	public fun <init> ()V
+	public fun <init> (Lspace/kscience/dataforge/meta/Config;)V
+	public synthetic fun <init> (Lspace/kscience/dataforge/meta/Config;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public synthetic fun build ()Lspace/kscience/dataforge/meta/descriptors/ItemDescriptor;
+	public fun build ()Lspace/kscience/dataforge/meta/descriptors/NodeDescriptor;
+	public fun getDefault ()Lspace/kscience/dataforge/meta/Config;
+	public fun getItems ()Ljava/util/Map;
+	public fun getNodes ()Ljava/util/Map;
+	public fun getRequired ()Z
+	public fun getValues ()Ljava/util/Map;
+	public final fun item (Ljava/lang/String;Lspace/kscience/dataforge/meta/descriptors/ItemDescriptor;)V
+	public final fun item (Lspace/kscience/dataforge/names/Name;Lspace/kscience/dataforge/meta/descriptors/ItemDescriptor;)V
+	public final fun node (Ljava/lang/String;Lkotlin/jvm/functions/Function1;)V
+	public final fun node (Lspace/kscience/dataforge/names/Name;Lkotlin/jvm/functions/Function1;)V
+	public fun setDefault (Lspace/kscience/dataforge/meta/Config;)V
+	public fun setRequired (Z)V
+	public final fun value (Ljava/lang/String;Lkotlin/jvm/functions/Function1;)V
+	public final fun value (Lspace/kscience/dataforge/names/Name;Lkotlin/jvm/functions/Function1;)V
+}
+
+public final class space/kscience/dataforge/meta/descriptors/NodeDescriptorBuilder$Companion {
+}
+
+public final class space/kscience/dataforge/meta/descriptors/NodeDescriptorKt {
+	public static final fun NodeDescriptor (Lkotlin/jvm/functions/Function1;)Lspace/kscience/dataforge/meta/descriptors/NodeDescriptor;
+	public static final fun plus (Lspace/kscience/dataforge/meta/descriptors/NodeDescriptor;Lspace/kscience/dataforge/meta/descriptors/NodeDescriptor;)Lspace/kscience/dataforge/meta/descriptors/NodeDescriptor;
+}
+
+public abstract interface class space/kscience/dataforge/meta/descriptors/ValueDescriptor : space/kscience/dataforge/meta/descriptors/ItemDescriptor {
+	public abstract fun getAllowedValues ()Ljava/util/List;
+	public abstract fun getDefault ()Lspace/kscience/dataforge/values/Value;
+	public abstract fun getRequired ()Z
+	public abstract fun getType ()Ljava/util/List;
+	public fun isAllowedValue (Lspace/kscience/dataforge/values/Value;)Z
+}
+
+public final class space/kscience/dataforge/meta/descriptors/ValueDescriptorBuilder : space/kscience/dataforge/meta/descriptors/ItemDescriptorBuilder, space/kscience/dataforge/meta/descriptors/ValueDescriptor {
 	public fun <init> ()V
 	public fun <init> (Lspace/kscience/dataforge/meta/Config;)V
 	public synthetic fun <init> (Lspace/kscience/dataforge/meta/Config;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun allow ([Ljava/lang/Object;)V
-	public synthetic fun copy ()Lspace/kscience/dataforge/meta/descriptors/ItemDescriptor;
-	public fun copy ()Lspace/kscience/dataforge/meta/descriptors/ValueDescriptor;
+	public synthetic fun build ()Lspace/kscience/dataforge/meta/descriptors/ItemDescriptor;
+	public fun build ()Lspace/kscience/dataforge/meta/descriptors/ValueDescriptor;
 	public final fun default (Ljava/lang/Object;)V
-	public final fun getAllowedValues ()Ljava/util/List;
-	public final fun getDefault ()Lspace/kscience/dataforge/values/Value;
+	public fun getAllowedValues ()Ljava/util/List;
+	public fun getDefault ()Lspace/kscience/dataforge/values/Value;
 	public fun getRequired ()Z
-	public final fun getType ()Ljava/util/List;
-	public final fun isAllowedValue (Lspace/kscience/dataforge/values/Value;)Z
-	public final fun setAllowedValues (Ljava/util/List;)V
-	public final fun setDefault (Lspace/kscience/dataforge/values/Value;)V
+	public fun getType ()Ljava/util/List;
+	public fun isAllowedValue (Lspace/kscience/dataforge/values/Value;)Z
+	public fun setAllowedValues (Ljava/util/List;)V
+	public fun setDefault (Lspace/kscience/dataforge/values/Value;)V
 	public fun setRequired (Z)V
-	public final fun setType (Ljava/util/List;)V
+	public fun setType (Ljava/util/List;)V
 	public final fun type ([Lspace/kscience/dataforge/values/ValueType;)V
 }
 
@@ -689,7 +704,6 @@ public final class space/kscience/dataforge/meta/transformations/RegexItemTransf
 	public final fun getTransform ()Lkotlin/jvm/functions/Function4;
 	public fun hashCode ()I
 	public fun matches (Lspace/kscience/dataforge/names/Name;Lspace/kscience/dataforge/meta/TypedMetaItem;)Z
-	public fun selectItems (Lspace/kscience/dataforge/meta/Meta;)Lkotlin/sequences/Sequence;
 	public fun toString ()Ljava/lang/String;
 	public fun transformItem (Lspace/kscience/dataforge/names/Name;Lspace/kscience/dataforge/meta/TypedMetaItem;Lspace/kscience/dataforge/meta/MutableMeta;)V
 }
@@ -712,14 +726,10 @@ public final class space/kscience/dataforge/meta/transformations/SingleItemTrans
 
 public abstract interface class space/kscience/dataforge/meta/transformations/TransformationRule {
 	public abstract fun matches (Lspace/kscience/dataforge/names/Name;Lspace/kscience/dataforge/meta/TypedMetaItem;)Z
-	public abstract fun selectItems (Lspace/kscience/dataforge/meta/Meta;)Lkotlin/sequences/Sequence;
+	public fun selectItems (Lspace/kscience/dataforge/meta/Meta;)Lkotlin/sequences/Sequence;
 	public abstract fun transformItem (Lspace/kscience/dataforge/names/Name;Lspace/kscience/dataforge/meta/TypedMetaItem;Lspace/kscience/dataforge/meta/MutableMeta;)V
 }
 
-public final class space/kscience/dataforge/meta/transformations/TransformationRule$DefaultImpls {
-	public static fun selectItems (Lspace/kscience/dataforge/meta/transformations/TransformationRule;Lspace/kscience/dataforge/meta/Meta;)Lkotlin/sequences/Sequence;
-}
-
 public abstract interface annotation class space/kscience/dataforge/misc/DFBuilder : java/lang/annotation/Annotation {
 }
 
@@ -852,7 +862,6 @@ public final class space/kscience/dataforge/values/DoubleArrayValue : java/lang/
 public final class space/kscience/dataforge/values/EnumValue : space/kscience/dataforge/values/Value {
 	public fun <init> (Ljava/lang/Enum;)V
 	public fun equals (Ljava/lang/Object;)Z
-	public fun getList ()Ljava/util/List;
 	public fun getType ()Lspace/kscience/dataforge/values/ValueType;
 	public fun getValue ()Ljava/lang/Enum;
 	public synthetic fun getValue ()Ljava/lang/Object;
@@ -868,7 +877,6 @@ public final class space/kscience/dataforge/values/ExoticValuesKt {
 public final class space/kscience/dataforge/values/False : space/kscience/dataforge/values/Value {
 	public static final field INSTANCE Lspace/kscience/dataforge/values/False;
 	public fun equals (Ljava/lang/Object;)Z
-	public fun getList ()Ljava/util/List;
 	public fun getType ()Lspace/kscience/dataforge/values/ValueType;
 	public fun getValue ()Ljava/lang/Object;
 	public fun hashCode ()I
@@ -878,7 +886,6 @@ public final class space/kscience/dataforge/values/False : space/kscience/datafo
 public final class space/kscience/dataforge/values/LazyParsedValue : space/kscience/dataforge/values/Value {
 	public fun <init> (Ljava/lang/String;)V
 	public fun equals (Ljava/lang/Object;)Z
-	public fun getList ()Ljava/util/List;
 	public final fun getString ()Ljava/lang/String;
 	public fun getType ()Lspace/kscience/dataforge/values/ValueType;
 	public fun getValue ()Ljava/lang/Object;
@@ -906,7 +913,6 @@ public final class space/kscience/dataforge/values/ListValue$Companion {
 public final class space/kscience/dataforge/values/Null : space/kscience/dataforge/values/Value {
 	public static final field INSTANCE Lspace/kscience/dataforge/values/Null;
 	public fun equals (Ljava/lang/Object;)Z
-	public fun getList ()Ljava/util/List;
 	public fun getType ()Lspace/kscience/dataforge/values/ValueType;
 	public fun getValue ()Ljava/lang/Object;
 	public fun hashCode ()I
@@ -916,7 +922,6 @@ public final class space/kscience/dataforge/values/Null : space/kscience/datafor
 public final class space/kscience/dataforge/values/NumberValue : space/kscience/dataforge/values/Value {
 	public fun <init> (Ljava/lang/Number;)V
 	public fun equals (Ljava/lang/Object;)Z
-	public fun getList ()Ljava/util/List;
 	public final fun getNumber ()Ljava/lang/Number;
 	public fun getType ()Lspace/kscience/dataforge/values/ValueType;
 	public fun getValue ()Ljava/lang/Object;
@@ -927,7 +932,6 @@ public final class space/kscience/dataforge/values/NumberValue : space/kscience/
 public final class space/kscience/dataforge/values/StringValue : space/kscience/dataforge/values/Value {
 	public fun <init> (Ljava/lang/String;)V
 	public fun equals (Ljava/lang/Object;)Z
-	public fun getList ()Ljava/util/List;
 	public final fun getString ()Ljava/lang/String;
 	public fun getType ()Lspace/kscience/dataforge/values/ValueType;
 	public fun getValue ()Ljava/lang/Object;
@@ -938,7 +942,6 @@ public final class space/kscience/dataforge/values/StringValue : space/kscience/
 public final class space/kscience/dataforge/values/True : space/kscience/dataforge/values/Value {
 	public static final field INSTANCE Lspace/kscience/dataforge/values/True;
 	public fun equals (Ljava/lang/Object;)Z
-	public fun getList ()Ljava/util/List;
 	public fun getType ()Lspace/kscience/dataforge/values/ValueType;
 	public fun getValue ()Ljava/lang/Object;
 	public fun hashCode ()I
@@ -949,7 +952,7 @@ public abstract interface class space/kscience/dataforge/values/Value {
 	public static final field Companion Lspace/kscience/dataforge/values/Value$Companion;
 	public static final field TYPE Ljava/lang/String;
 	public abstract fun equals (Ljava/lang/Object;)Z
-	public abstract fun getList ()Ljava/util/List;
+	public fun getList ()Ljava/util/List;
 	public abstract fun getType ()Lspace/kscience/dataforge/values/ValueType;
 	public abstract fun getValue ()Ljava/lang/Object;
 	public abstract fun hashCode ()I
@@ -961,10 +964,6 @@ public final class space/kscience/dataforge/values/Value$Companion {
 	public final fun of (Ljava/lang/Object;)Lspace/kscience/dataforge/values/Value;
 }
 
-public final class space/kscience/dataforge/values/Value$DefaultImpls {
-	public static fun getList (Lspace/kscience/dataforge/values/Value;)Ljava/util/List;
-}
-
 public final class space/kscience/dataforge/values/ValueExtensionsKt {
 	public static final fun getBoolean (Lspace/kscience/dataforge/values/Value;)Z
 	public static final fun getDouble (Lspace/kscience/dataforge/values/Value;)D
diff --git a/settings.gradle.kts b/settings.gradle.kts
index 6db60f3d..a5bf754f 100644
--- a/settings.gradle.kts
+++ b/settings.gradle.kts
@@ -2,13 +2,11 @@ pluginManagement {
     repositories {
         maven("https://repo.kotlin.link")
         mavenCentral()
-        jcenter()
         gradlePluginPortal()
-        maven("https://dl.bintray.com/kotlin/kotlin-eap")
     }
 
-    val toolsVersion = "0.9.5-dev"
-    val kotlinVersion = "1.5.0-M2"
+    val toolsVersion = "0.9.5"
+    val kotlinVersion = "1.5.0"
 
     plugins {
         id("ru.mipt.npm.gradle.project") version toolsVersion