Configurable and Scheme revision

README.md

@@ -1,8 +1,11 @@
 [![JetBrains Research](https://jb.gg/badges/research.svg)](https://confluence.jetbrains.com/display/ALL/JetBrains+on+GitHub)
+[![DOI](https://zenodo.org/badge/148831678.svg)](https://zenodo.org/badge/latestdoi/148831678)
+
+![Gradle build](https://github.com/mipt-npm/dataforge-core/workflows/Gradle%20build/badge.svg)
 
 [ ![Download](https://api.bintray.com/packages/mipt-npm/dataforge/dataforge-meta/images/download.svg) ](https://bintray.com/mipt-npm/dataforge/dataforge-meta/_latestVersion)
 
-[![DOI](https://zenodo.org/badge/148831678.svg)](https://zenodo.org/badge/latestdoi/148831678)
+
 
 # Questions and Answers #
 

build.gradle.kts

@@ -6,7 +6,7 @@ plugins {
     id("scientifik.publish") version toolsVersion apply false
 }
 
-val dataforgeVersion by extra("0.1.5-dev-6")
+val dataforgeVersion by extra("0.1.5-dev-7")
 
 val bintrayRepo by extra("dataforge")
 val githubProject by extra("dataforge-core")

dataforge-data/src/commonMain/kotlin/hep/dataforge/data/DataFilter.kt

@@ -4,7 +4,7 @@ import hep.dataforge.meta.*
 import hep.dataforge.names.toName
 
 
-class DataFilter(override val config: Config) : Specific {
+class DataFilter : Scheme() {
     /**
      * A source node for the filter
      */
@@ -22,9 +22,7 @@ class DataFilter(override val config: Config) : Specific {
 
     fun isEmpty(): Boolean = config.isEmpty()
 
-    companion object : Specification<DataFilter> {
+    companion object : SchemeSpec<DataFilter>(::DataFilter)
-        override fun wrap(config: Config): DataFilter = DataFilter(config)
-    }
 }
 
 /**

dataforge-io/src/commonMain/kotlin/hep/dataforge/io/serialization/MetaSerializer.kt

@@ -133,7 +133,7 @@ object ConfigSerializer : KSerializer<Config> {
     override val descriptor: SerialDescriptor = MetaSerializer.descriptor
 
     override fun deserialize(decoder: Decoder): Config {
-        return MetaSerializer.deserialize(decoder).toConfig()
+        return MetaSerializer.deserialize(decoder).asConfig()
     }
 
     override fun serialize(encoder: Encoder, obj: Config) {

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

@@ -1,29 +1,24 @@
 package hep.dataforge.descriptors
 
-import hep.dataforge.descriptors.Described.Companion.DESCRIPTOR_NODE
-import hep.dataforge.meta.MetaRepr
-import hep.dataforge.meta.get
-import hep.dataforge.meta.node
-
 /**
  * An object which provides its descriptor
  */
 interface Described {
-    val descriptor: NodeDescriptor
+    val descriptor: NodeDescriptor?
 
     companion object {
         const val DESCRIPTOR_NODE = "@descriptor"
     }
 }
 
-/**
+///**
- * If meta node supplies explicit descriptor, return it, otherwise try to use descriptor node from meta itself
+// * If meta node supplies explicit descriptor, return it, otherwise try to use descriptor node from meta itself
- */
+// */
-val MetaRepr.descriptor: NodeDescriptor?
+//val MetaRepr.descriptor: NodeDescriptor?
-    get() {
+//    get() {
-        return if (this is Described) {
+//        return if (this is Described) {
-            descriptor
+//            descriptor
-        } else {
+//        } else {
-            toMeta()[DESCRIPTOR_NODE].node?.let { NodeDescriptor.wrap(it) }
+//            toMeta()[DESCRIPTOR_NODE].node?.let { NodeDescriptor.wrap(it) }
-        }
+//        }
-    }
+//    }

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

@@ -0,0 +1,28 @@
+package hep.dataforge.descriptors
+
+import hep.dataforge.meta.MetaBase
+import hep.dataforge.meta.MetaItem
+import hep.dataforge.names.NameToken
+import hep.dataforge.values.Null
+
+class DescriptorMeta(val descriptor: NodeDescriptor) : MetaBase() {
+    override val items: Map<NameToken, MetaItem<*>>
+        get() = descriptor.items.entries.associate { entry ->
+            NameToken(entry.key) to entry.value.defaultItem()
+        }
+}
+
+fun NodeDescriptor.defaultItem(): MetaItem.NodeItem<*> =
+    MetaItem.NodeItem(default ?: DescriptorMeta(this))
+
+fun ValueDescriptor.defaultItem(): MetaItem.ValueItem = MetaItem.ValueItem(default ?: Null)
+
+/**
+ * Build a default [MetaItem] from descriptor.
+ */
+fun ItemDescriptor.defaultItem(): MetaItem<*> {
+    return when (this) {
+        is ValueDescriptor -> defaultItem()
+        is NodeDescriptor -> defaultItem()
+    }
+}

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

@@ -4,12 +4,13 @@ import hep.dataforge.meta.*
 import hep.dataforge.names.Name
 import hep.dataforge.names.NameToken
 import hep.dataforge.names.asName
+import hep.dataforge.names.isEmpty
 import hep.dataforge.values.False
 import hep.dataforge.values.True
 import hep.dataforge.values.Value
 import hep.dataforge.values.ValueType
 
-sealed class ItemDescriptor(override val config: Config) : Specific {
+sealed class ItemDescriptor : Scheme() {
 
     /**
      * True if same name siblings with this name are allowed
@@ -30,7 +31,7 @@ sealed class ItemDescriptor(override val config: Config) : Specific {
      *
      * @return
      */
-    var attributes by child()
+    var attributes by config()
 
     /**
      * True if the item is required
@@ -46,7 +47,7 @@ sealed class ItemDescriptor(override val config: Config) : Specific {
  *
  * @author Alexander Nozik
  */
-class NodeDescriptor(config: Config) : ItemDescriptor(config) {
+class NodeDescriptor : ItemDescriptor() {
 
     /**
      * True if the node is required
@@ -60,7 +61,7 @@ class NodeDescriptor(config: Config) : ItemDescriptor(config) {
      *
      * @return
      */
-    var default: Config? by child()
+    var default: Config? by nullableConfig()
 
     /**
      * The map of children node descriptors
@@ -134,18 +135,28 @@ class NodeDescriptor(config: Config) : ItemDescriptor(config) {
 
     //override val descriptor: NodeDescriptor =  empty("descriptor")
 
-    companion object : Specification<NodeDescriptor> {
+    companion object : SchemeSpec<NodeDescriptor>(::NodeDescriptor) {
 
         //        const val ITEM_KEY = "item"
         const val NODE_KEY = "node"
         const val VALUE_KEY = "value"
 
-        override fun wrap(config: Config): NodeDescriptor = NodeDescriptor(config)
+        //override fun wrap(config: Config): NodeDescriptor = NodeDescriptor(config)
 
         //TODO infer descriptor from spec
     }
 }
 
+/**
+ * Get a descriptor item associated with given name or null if item for given name not provided
+ */
+operator fun ItemDescriptor.get(name: Name): ItemDescriptor? {
+    if (name.isEmpty()) return this
+    return when (this) {
+        is ValueDescriptor -> null // empty name already checked
+        is NodeDescriptor -> items[name.first()!!.toString()]?.get(name.cutFirst())
+    }
+}
 
 /**
  * A descriptor for meta value
@@ -154,7 +165,7 @@ class NodeDescriptor(config: Config) : ItemDescriptor(config) {
  *
  * @author Alexander Nozik
  */
-class ValueDescriptor(config: Config) : ItemDescriptor(config) {
+class ValueDescriptor : ItemDescriptor() {
 
 
     /**
@@ -180,8 +191,8 @@ class ValueDescriptor(config: Config) : ItemDescriptor(config) {
      *
      * @return
      */
-    var type: List<ValueType> by value {
+    var type: List<ValueType> by item {
-        it?.list?.map { v -> ValueType.valueOf(v.string) } ?: emptyList()
+        it?.value?.list?.map { v -> ValueType.valueOf(v.string) } ?: emptyList()
     }
 
     fun type(vararg t: ValueType) {
@@ -222,10 +233,7 @@ class ValueDescriptor(config: Config) : ItemDescriptor(config) {
         this.allowedValues = v.map { Value.of(it) }
     }
 
-    companion object : Specification<ValueDescriptor> {
+    companion object : SchemeSpec<ValueDescriptor>(::ValueDescriptor) {
-
-        override fun wrap(config: Config): ValueDescriptor = ValueDescriptor(config)
-
         inline fun <reified E : Enum<E>> enum(name: String) = ValueDescriptor {
             type(ValueType.STRING)
             this.allowedValues = enumValues<E>().map { Value.of(it.name) }
@@ -289,4 +297,4 @@ class ValueDescriptor(config: Config) : ItemDescriptor(config) {
 //            return ValueDescriptor(Laminate(primary.meta, secondary.meta))
 //        }
     }
-}
+}

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

@@ -40,7 +40,7 @@ class Config : AbstractMutableMeta<Config>() {
     override fun replaceItem(key: NameToken, oldItem: MetaItem<Config>?, newItem: MetaItem<Config>?) {
         if (newItem == null) {
             _items.remove(key)
-            if(oldItem!= null && oldItem is MetaItem.NodeItem<Config>) {
+            if (oldItem != null && oldItem is MetaItem.NodeItem<Config>) {
                 oldItem.node.removeListener(this)
             }
         } else {
@@ -57,7 +57,7 @@ class Config : AbstractMutableMeta<Config>() {
     /**
      * Attach configuration node instead of creating one
      */
-    override fun wrapNode(meta: Meta): Config = meta.toConfig()
+    override fun wrapNode(meta: Meta): Config = meta.asConfig()
 
     override fun empty(): Config = Config()
 
@@ -68,22 +68,12 @@ class Config : AbstractMutableMeta<Config>() {
 
 operator fun Config.get(token: NameToken): MetaItem<Config>? = items[token]
 
-fun Meta.toConfig(): Config = this as? Config ?: Config().also { builder ->
+fun Meta.asConfig(): Config = this as? Config ?: Config().also { builder ->
     this.items.mapValues { entry ->
         val item = entry.value
         builder[entry.key.asName()] = when (item) {
             is MetaItem.ValueItem -> item.value
-            is MetaItem.NodeItem -> MetaItem.NodeItem(item.node.toConfig())
+            is MetaItem.NodeItem -> MetaItem.NodeItem(item.node.asConfig())
         }
     }
-}
+}
-
-interface Configurable {
-    val config: Config
-}
-
-fun <T : Configurable> T.configure(meta: Meta): T = this.apply { config.update(meta) }
-
-fun <T : Configurable> T.configure(action: MetaBuilder.() -> Unit): T = configure(buildMeta(action))
-
-open class SimpleConfigurable(override val config: Config) : Configurable

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

@@ -0,0 +1,44 @@
+package hep.dataforge.meta
+
+import hep.dataforge.names.Name
+import hep.dataforge.names.toName
+
+/**
+ * A container that holds a [Config] and a default item provider.
+ * Default item provider could be use for example to reference parent configuration.
+ * It is not possible to know if some property is declared by provider just by looking on [Configurable],
+ * this information should be provided externally.
+ */
+interface Configurable {
+    /**
+     * Backing config
+     */
+    val config: Config
+
+    /**
+     * Default meta item provider
+     */
+    fun getDefaultItem(name: Name): MetaItem<*>? = null
+}
+
+/**
+ * Get a property with default
+ */
+fun Configurable.getProperty(name: Name): MetaItem<*>? = config[name] ?: getDefaultItem(name)
+
+fun Configurable.getProperty(key: String) = getProperty(key.toName())
+
+/**
+ * Set a configurable property
+ */
+fun Configurable.setProperty(name: Name, item: MetaItem<*>?) {
+    config[name] = item
+}
+
+fun Configurable.setProperty(key: String, item: MetaItem<*>?) {
+    setProperty(key.toName(), item)
+}
+
+fun <T : Configurable> T.configure(meta: Meta): T = this.apply { config.update(meta) }
+
+fun <T : Configurable> T.configure(action: Config.() -> Unit): T = apply { config.apply(action) }

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

@@ -1,9 +1,10 @@
 package hep.dataforge.meta
 
+import hep.dataforge.names.Name
 import hep.dataforge.names.NameToken
 
 /**
- * A meta laminate consisting of multiple immutable meta layers. For mutable front layer, use [Styled].
+ * A meta laminate consisting of multiple immutable meta layers. For mutable front layer, use [Scheme].
  */
 class Laminate(layers: List<Meta>) : MetaBase() {
 
@@ -17,10 +18,11 @@ class Laminate(layers: List<Meta>) : MetaBase() {
 
     constructor(vararg layers: Meta?) : this(layers.filterNotNull())
 
-    override val items: Map<NameToken, MetaItem<Meta>>
+    override val items: Map<NameToken, MetaItem<Meta>> by lazy {
-        get() = layers.map { it.items.keys }.flatten().associateWith { key ->
+        layers.map { it.items.keys }.flatten().associateWith { key ->
             layers.asSequence().map { it.items[key] }.filterNotNull().let(replaceRule)
         }
+    }
 
     /**
      * Generate sealed meta using [mergeRule]
@@ -77,6 +79,16 @@ class Laminate(layers: List<Meta>) : MetaBase() {
     }
 }
 
+/**
+ * Performance optimized version of get method
+ */
+fun Laminate.getFirst(name: Name): MetaItem<*>? {
+    layers.forEach { layer ->
+        layer[name]?.let { return it }
+    }
+    return null
+}
+
 /**
  * Create a new [Laminate] adding given layer to the top
  */

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

@@ -5,6 +5,7 @@ import hep.dataforge.meta.MetaItem.NodeItem
 import hep.dataforge.meta.MetaItem.ValueItem
 import hep.dataforge.names.*
 import hep.dataforge.values.EnumValue
+import hep.dataforge.values.Null
 import hep.dataforge.values.Value
 import hep.dataforge.values.boolean
 
@@ -22,6 +23,17 @@ sealed class MetaItem<out M : Meta> {
     data class NodeItem<M : Meta>(val node: M) : MetaItem<M>() {
         override fun toString(): String = node.toString()
     }
+
+    companion object {
+        fun of(arg: Any?): MetaItem<*> {
+            return when (arg) {
+                null -> ValueItem(Null)
+                is MetaItem<*> -> arg
+                is Meta -> NodeItem(arg)
+                else -> ValueItem(Value.of(arg))
+            }
+        }
+    }
 }
 
 /**
@@ -45,7 +57,7 @@ interface Meta : MetaRepr {
      */
     val items: Map<NameToken, MetaItem<*>>
 
-    override fun toMeta(): Meta = this
+    override fun toMeta(): Meta = seal()
 
     override fun equals(other: Any?): Boolean
 
@@ -69,7 +81,7 @@ interface Meta : MetaRepr {
 /**
  * Perform recursive item search using given [name]. Each [NameToken] is treated as a name in [Meta.items] of a parent node.
  *
- * If [name] is empty reture current [Meta] as a [NodeItem]
+ * If [name] is empty return current [Meta] as a [NodeItem]
  */
 operator fun Meta?.get(name: Name): MetaItem<*>? {
     if (this == null) return null
@@ -129,17 +141,8 @@ interface MetaNode<out M : MetaNode<M>> : Meta {
 /**
  * The same as [Meta.get], but with specific node type
  */
-operator fun <M : MetaNode<M>> M?.get(name: Name): MetaItem<M>? {
+@Suppress("UNCHECKED_CAST")
-    if (this == null) return null
+operator fun <M : MetaNode<M>> M?.get(name: Name): MetaItem<M>? = (this as Meta)[name] as MetaItem<M>?
-    if (name.isEmpty()) return NodeItem(this)
-    return name.first()?.let { token ->
-        val tail = name.cutFirst()
-        when (tail.length) {
-            0 -> items[token]
-            else -> items[token]?.node?.get(tail)
-        }
-    }
-}
 
 operator fun <M : MetaNode<M>> M?.get(key: String): MetaItem<M>? = this[key.toName()]
 

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

@@ -105,7 +105,7 @@ operator fun MutableMeta<*>.set(name: Name, value: Any?) {
         null -> remove(name)
         is MetaItem<*> -> setItem(name, value)
         is Meta -> setNode(name, value)
-        is Specific -> setNode(name, value.config)
+        is Configurable -> setNode(name, value.config)
         else -> setValue(name, Value.of(value))
     }
 }

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

@@ -0,0 +1,78 @@
+package hep.dataforge.meta
+
+import hep.dataforge.descriptors.*
+import hep.dataforge.names.Name
+import hep.dataforge.names.NameToken
+import hep.dataforge.names.plus
+
+open class Scheme() : Configurable, Described {
+    constructor(config: Config, defaultProvider: (Name) -> MetaItem<*>?) : this() {
+        this.config = config
+        this.defaultProvider = defaultProvider
+    }
+
+    //constructor(config: Config, default: Meta) : this(config, { default[it] })
+    constructor(config: Config) : this(config, { null })
+
+    final override lateinit var config: Config
+        internal set
+
+    lateinit var defaultProvider: (Name) -> MetaItem<*>?
+        internal set
+
+    override val descriptor: NodeDescriptor? = null
+
+    override fun getDefaultItem(name: Name): MetaItem<*>? {
+        return defaultProvider(name) ?: descriptor?.get(name)?.defaultItem()
+    }
+
+    /**
+     * Provide a default layer which returns items from [defaultProvider] and falls back to descriptor
+     * values if default value is unavailable.
+     * Values from [defaultProvider] completely replace
+     */
+    open val defaultLayer: Meta get() = DefaultLayer(Name.EMPTY)
+
+    private inner class DefaultLayer(val path: Name) : MetaBase() {
+        override val items: Map<NameToken, MetaItem<*>> =
+            (descriptor?.get(path) as? NodeDescriptor)?.items?.entries?.associate { (key, descriptor) ->
+                val token = NameToken(key)
+                val fullName = path + token
+                val item: MetaItem<*> = when (descriptor) {
+                    is ValueDescriptor -> getDefaultItem(fullName) ?: descriptor.defaultItem()
+                    is NodeDescriptor -> MetaItem.NodeItem(DefaultLayer(fullName))
+                }
+                token to item
+            } ?: emptyMap()
+    }
+
+}
+
+/**
+ * A specification for simplified generation of wrappers
+ */
+open class SchemeSpec<T : Scheme>(val builder: () -> T) : Specification<T> {
+    override fun wrap(config: Config, defaultProvider: (Name) -> MetaItem<*>?): T {
+        return builder().apply {
+            this.config = config
+            this.defaultProvider = defaultProvider
+        }
+    }
+}
+
+open class MetaScheme(
+    val meta: Meta,
+    override val descriptor: NodeDescriptor? = null,
+    config: Config = Config()
+) : Scheme(config, meta::get) {
+    override val defaultLayer: Meta get() = meta
+}
+
+fun Meta.toScheme() = MetaScheme(this)
+
+fun <T : Configurable> Meta.toScheme(spec: Specification<T>, block: T.() -> Unit) = spec.wrap(this).apply(block)
+
+/**
+ * Create a snapshot laminate
+ */
+fun Scheme.toMeta(): Laminate = Laminate(config, defaultLayer)

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

@@ -1,101 +0,0 @@
-package hep.dataforge.meta
-
-import hep.dataforge.names.Name
-import hep.dataforge.names.asName
-import kotlin.jvm.JvmName
-import kotlin.properties.ReadWriteProperty
-import kotlin.reflect.KProperty
-
-/**
- * Marker interface for classes with specifications
- */
-interface Specific : Configurable
-
-//TODO separate mutable config from immutable meta to allow free wrapping of meta
-
-operator fun Specific.get(name: String): MetaItem<*>? = config[name]
-
-/**
- * Editor for specific objects
- */
-inline operator fun <S : Specific> S.invoke(block: S.() -> Unit): Unit {
-    run(block)
-}
-
-/**
- * Allows to apply custom configuration in a type safe way to simple untyped configuration.
- * By convention [Specific] companion should inherit this class
- *
- */
-interface Specification<T : Specific> {
-    /**
-     * Update given configuration using given type as a builder
-     */
-    fun update(config: Config, action: T.() -> Unit): T {
-        return wrap(config).apply(action)
-    }
-
-    operator fun invoke(action: T.() -> Unit) = update(Config(), action)
-
-    fun empty() = wrap(Config())
-
-    /**
-     * Wrap generic configuration producing instance of desired type
-     */
-    fun wrap(config: Config): T
-
-    //TODO replace by free wrapper
-    fun wrap(meta: Meta): T = wrap(meta.toConfig())
-}
-
-fun <T : Specific> specification(wrapper: (Config) -> T): Specification<T> =
-    object : Specification<T> {
-        override fun wrap(config: Config): T = wrapper(config)
-    }
-
-/**
- * Apply specified configuration to configurable
- */
-fun <T : Configurable, C : Specific, S : Specification<C>> T.configure(spec: S, action: C.() -> Unit) =
-    apply { spec.update(config, action) }
-
-/**
- * Update configuration using given specification
- */
-fun <C : Specific, S : Specification<C>> Specific.update(spec: S, action: C.() -> Unit) =
-    apply { spec.update(config, action) }
-
-/**
- * Create a style based on given specification
- */
-fun <C : Specific, S : Specification<C>> S.createStyle(action: C.() -> Unit): Meta =
-    Config().also { update(it, action) }
-
-class SpecDelegate<T : Specific, S : Specification<T>>(
-    val target: Specific,
-    val spec: S,
-    val key: Name? = null
-) : ReadWriteProperty<Any?, T> {
-
-    override fun getValue(thisRef: Any?, property: KProperty<*>): T {
-        val name = key ?: property.name.asName()
-        return target.config[name]?.node?.let { spec.wrap(it) } ?: (spec.empty().also {
-            target.config[name] = it.config
-        })
-    }
-
-    override fun setValue(thisRef: Any?, property: KProperty<*>, value: T) {
-        target.config[key ?: property.name.asName()] = value.config
-    }
-}
-
-fun <T : Specific, S : Specification<T>> Specific.spec(
-    spec: S,
-    key: Name? = null
-): SpecDelegate<T, S> = SpecDelegate(this, spec, key)
-
-fun <T : Specific> MetaItem<*>.spec(spec: Specification<T>): T? = node?.let { spec.wrap(it) }
-
-@JvmName("configSpec")
-fun <T : Specific> MetaItem<Config>.spec(spec: Specification<T>): T? = node?.let { spec.wrap(it) }
-

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

@@ -0,0 +1,60 @@
+package hep.dataforge.meta
+
+import hep.dataforge.names.Name
+import kotlin.jvm.JvmName
+
+/**
+ * Allows to apply custom configuration in a type safe way to simple untyped configuration.
+ * By convention [Scheme] companion should inherit this class
+ *
+ */
+interface Specification<T : Configurable> {
+    /**
+     * Update given configuration using given type as a builder
+     */
+    fun update(config: Config, action: T.() -> Unit): T {
+        return wrap(config).apply(action)
+    }
+
+    operator fun invoke(action: T.() -> Unit) = update(Config(), action)
+
+    fun empty() = wrap()
+
+    /**
+     * Wrap generic configuration producing instance of desired type
+     */
+    fun wrap(config: Config = Config(), defaultProvider: (Name) -> MetaItem<*>? = { null }): T
+
+    /**
+     * Wrap a configuration using static meta as default
+     */
+    fun wrap(config: Config = Config(), default: Meta): T = wrap(config){default[it]}
+
+    /**
+     * Wrap a configuration using static meta as default
+     */
+    fun wrap(default: Meta): T = wrap(Config()){default[it]}
+}
+
+/**
+ * Apply specified configuration to configurable
+ */
+fun <T : Configurable, C : Configurable, S : Specification<C>> T.configure(spec: S, action: C.() -> Unit) =
+    apply { spec.update(config, action) }
+
+/**
+ * Update configuration using given specification
+ */
+fun <C : Configurable, S : Specification<C>> Configurable.update(spec: S, action: C.() -> Unit) =
+    apply { spec.update(config, action) }
+
+/**
+ * Create a style based on given specification
+ */
+fun <C : Configurable, S : Specification<C>> S.createStyle(action: C.() -> Unit): Meta =
+    Config().also { update(it, action) }
+
+fun <T : Configurable> MetaItem<*>.spec(spec: Specification<T>): T? = node?.let { spec.wrap(Config(), it) }
+
+@JvmName("configSpec")
+fun <T : Configurable> MetaItem<Config>.spec(spec: Specification<T>): T? = node?.let { spec.wrap(it) }

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

@@ -1,72 +0,0 @@
-package hep.dataforge.meta
-
-import hep.dataforge.names.Name
-import hep.dataforge.names.NameToken
-import kotlin.properties.ReadWriteProperty
-import kotlin.reflect.KProperty
-
-
-/**
- * A meta object with read-only meta base and changeable configuration on top of it
- * @param base - unchangeable base
- * @param style - the style
- */
-class Styled(val base: Meta, val style: Config = Config().empty()) : AbstractMutableMeta<Styled>() {
-    override fun wrapNode(meta: Meta): Styled  = Styled(meta)
-
-    override fun empty(): Styled  = Styled(EmptyMeta)
-
-    override val items: Map<NameToken, MetaItem<Styled>>
-        get() = (base.items.keys + style.items.keys).associate { key ->
-            val value = base.items[key]
-            val styleValue = style[key]
-            val item: MetaItem<Styled> = when (value) {
-                null -> when (styleValue) {
-                    null -> error("Should be unreachable")
-                    is MetaItem.NodeItem -> MetaItem.NodeItem(Styled(style.empty(), styleValue.node))
-                    is MetaItem.ValueItem -> styleValue
-                }
-                is MetaItem.ValueItem -> value
-                is MetaItem.NodeItem -> MetaItem.NodeItem(
-                    Styled(value.node, styleValue?.node ?: Config.empty())
-                )
-            }
-            key to item
-        }
-
-    override fun set(name: Name, item: MetaItem<*>?) {
-        if (item == null) {
-            style.remove(name)
-        } else {
-            style[name] = item
-        }
-    }
-
-    fun onChange(owner: Any?, action: (Name, before: MetaItem<*>?, after: MetaItem<*>?) -> Unit) {
-        //TODO test correct behavior
-        style.onChange(owner) { name, before, after -> action(name, before ?: base[name], after ?: base[name]) }
-    }
-
-    fun removeListener(owner: Any?) {
-        style.removeListener(owner)
-    }
-}
-
-fun Styled.configure(meta: Meta) = apply { style.update(meta) }
-
-fun Meta.withStyle(style: Meta = EmptyMeta) = if (this is Styled) {
-    this.apply { this.configure(style) }
-} else {
-    Styled(this, style.toConfig())
-}
-
-class StyledNodeDelegate(val owner: Styled, val key: String?) : ReadWriteProperty<Any?, Meta> {
-    override fun getValue(thisRef: Any?, property: KProperty<*>): Meta {
-        return owner[key ?: property.name]?.node ?: EmptyMeta
-    }
-
-    override fun setValue(thisRef: Any?, property: KProperty<*>, value: Meta) {
-        owner.style[key ?: property.name] = value
-    }
-
-}

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

@@ -1,137 +0,0 @@
-package hep.dataforge.meta
-
-import hep.dataforge.names.Name
-import hep.dataforge.values.DoubleArrayValue
-import hep.dataforge.values.Null
-import hep.dataforge.values.Value
-import kotlin.jvm.JvmName
-
-
-//Configurable delegates
-
-/**
- * A property delegate that uses custom key
- */
-fun Configurable.value(default: Any = Null, key: Name? = null): MutableValueDelegate<Config> =
-    MutableValueDelegate(config, key, Value.of(default))
-
-fun <T> Configurable.value(
-    default: T? = null,
-    key: Name? = null,
-    writer: (T) -> Value = { Value.of(it) },
-    reader: (Value?) -> T
-): ReadWriteDelegateWrapper<Value?, T> =
-    MutableValueDelegate(config, key, default?.let { Value.of(it) }).transform(reader = reader, writer = writer)
-
-fun Configurable.string(default: String? = null, key: Name? = null): MutableStringDelegate<Config> =
-    MutableStringDelegate(config, key, default)
-
-fun Configurable.boolean(default: Boolean? = null, key: Name? = null): MutableBooleanDelegate<Config> =
-    MutableBooleanDelegate(config, key, default)
-
-fun Configurable.number(default: Number? = null, key: Name? = null): MutableNumberDelegate<Config> =
-    MutableNumberDelegate(config, key, default)
-
-/* Number delegates*/
-
-fun Configurable.int(default: Int? = null, key: Name? = null) =
-    number(default, key).int
-
-fun Configurable.double(default: Double? = null, key: Name? = null) =
-    number(default, key).double
-
-fun Configurable.long(default: Long? = null, key: Name? = null) =
-    number(default, key).long
-
-fun Configurable.short(default: Short? = null, key: Name? = null) =
-    number(default, key).short
-
-fun Configurable.float(default: Float? = null, key: Name? = null) =
-    number(default, key).float
-
-
-@JvmName("safeString")
-fun Configurable.string(default: String, key: Name? = null) =
-    MutableSafeStringDelegate(config, key) { default }
-
-@JvmName("safeBoolean")
-fun Configurable.boolean(default: Boolean, key: Name? = null) =
-    MutableSafeBooleanDelegate(config, key) { default }
-
-@JvmName("safeNumber")
-fun Configurable.number(default: Number, key: Name? = null) =
-    MutableSafeNumberDelegate(config, key) { default }
-
-@JvmName("safeString")
-fun Configurable.string(key: Name? = null, default: () -> String) =
-    MutableSafeStringDelegate(config, key, default)
-
-@JvmName("safeBoolean")
-fun Configurable.boolean(key: Name? = null, default: () -> Boolean) =
-    MutableSafeBooleanDelegate(config, key, default)
-
-@JvmName("safeNumber")
-fun Configurable.number(key: Name? = null, default: () -> Number) =
-    MutableSafeNumberDelegate(config, key, default)
-
-
-/* Safe number delegates*/
-
-@JvmName("safeInt")
-fun Configurable.int(default: Int, key: Name? = null) =
-    number(default, key).int
-
-@JvmName("safeDouble")
-fun Configurable.double(default: Double, key: Name? = null) =
-    number(default, key).double
-
-@JvmName("safeLong")
-fun Configurable.long(default: Long, key: Name? = null) =
-    number(default, key).long
-
-@JvmName("safeShort")
-fun Configurable.short(default: Short, key: Name? = null) =
-    number(default, key).short
-
-@JvmName("safeFloat")
-fun Configurable.float(default: Float, key: Name? = null) =
-    number(default, key).float
-
-/**
- * Enum delegate
- */
-inline fun <reified E : Enum<E>> Configurable.enum(default: E, key: Name? = null) =
-    MutableSafeEnumvDelegate(config, key, default) { enumValueOf(it) }
-
-/* Node delegates */
-
-fun Configurable.child(key: Name? = null): MutableNodeDelegate<Config> = MutableNodeDelegate(config, key)
-
-fun <T : Specific> Configurable.spec(spec: Specification<T>, key: Name? = null) =
-    MutableMorphDelegate(config, key) { spec.wrap(it) }
-
-fun <T : Specific> Configurable.spec(builder: (Config) -> T, key: Name? = null) =
-    MutableMorphDelegate(config, key) { specification(builder).wrap(it) }
-
-/*
- * Extra delegates for special cases
- */
-
-fun Configurable.stringList(vararg strings: String, key: Name? = null): ReadWriteDelegateWrapper<Value?, List<String>> =
-    value(strings.asList(), key) { it?.list?.map { value -> value.string } ?: emptyList() }
-
-fun Configurable.numberList(vararg numbers: Number, key: Name? = null): ReadWriteDelegateWrapper<Value?, List<Number>> =
-    value(numbers.asList(), key) { it?.list?.map { value -> value.number } ?: emptyList() }
-
-/**
- * A special delegate for double arrays
- */
-fun Configurable.doubleArray(key: Name? = null): ReadWriteDelegateWrapper<Value?, DoubleArray> =
-    value(doubleArrayOf(), key) {
-        (it as? DoubleArrayValue)?.value
-            ?: it?.list?.map { value -> value.number.toDouble() }?.toDoubleArray()
-            ?: doubleArrayOf()
-    }
-
-fun <T : Configurable> Configurable.child(key: Name? = null, converter: (Meta) -> T) =
-    MutableMorphDelegate(config, key, converter)

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

@@ -0,0 +1,236 @@
+package hep.dataforge.meta
+
+import hep.dataforge.names.Name
+import hep.dataforge.names.asName
+import hep.dataforge.values.*
+import kotlin.jvm.JvmName
+import kotlin.properties.ReadWriteProperty
+import kotlin.reflect.KProperty
+
+
+//delegates
+
+/**
+ * A delegate that uses a [Configurable] object and delegate read and write operations to its properties
+ */
+open class ConfigurableDelegate(
+    val owner: Configurable,
+    val key: Name? = null,
+    open val default: MetaItem<*>? = null
+) : ReadWriteProperty<Any?, MetaItem<*>?> {
+
+    override fun getValue(thisRef: Any?, property: KProperty<*>): MetaItem<*>? {
+        val name = key ?: property.name.asName()
+        return owner.getProperty(name) ?: default
+    }
+
+    override fun setValue(thisRef: Any?, property: KProperty<*>, value: MetaItem<*>?) {
+        val name = key ?: property.name.asName()
+        owner.setProperty(name, value)
+    }
+
+    fun <T> transform(
+        writer: (T) -> MetaItem<*>? = { MetaItem.of(it) },
+        reader: (MetaItem<*>?) -> T
+    ): ReadWriteProperty<Any?, T> = object : ReadWriteProperty<Any?, T> {
+        override fun getValue(thisRef: Any?, property: KProperty<*>): T {
+            return reader(this@ConfigurableDelegate.getValue(thisRef, property))
+        }
+
+        override fun setValue(thisRef: Any?, property: KProperty<*>, value: T) {
+            this@ConfigurableDelegate.setValue(thisRef, property, writer(value))
+        }
+    }
+}
+
+class LazyConfigurableDelegate(
+    configurable: Configurable,
+    key: Name? = null,
+    defaultProvider: () -> MetaItem<*>? = { null }
+) : ConfigurableDelegate(configurable, key) {
+    override val default by lazy(defaultProvider)
+}
+
+/**
+ * A property delegate that uses custom key
+ */
+fun Configurable.item(default: Any?, key: Name? = null): ConfigurableDelegate =
+    ConfigurableDelegate(this, key, MetaItem.of(default))
+
+/**
+ * Generation of item delegate with lazy default.
+ * Lazy default could be used also for validation
+ */
+fun Configurable.lazyItem(key: Name? = null, default: () -> Any?): ConfigurableDelegate =
+    LazyConfigurableDelegate(this, key) { default()?.let { MetaItem.of(it) } }
+
+fun <T> Configurable.item(
+    default: T? = null,
+    key: Name? = null,
+    writer: (T) -> MetaItem<*>? = { MetaItem.of(it) },
+    reader: (MetaItem<*>?) -> T
+): ReadWriteProperty<Any?, T> =
+    ConfigurableDelegate(this, key, default?.let { MetaItem.of(it) }).transform(reader = reader, writer = writer)
+
+fun Configurable.value(default: Any? = null, key: Name? = null): ReadWriteProperty<Any?, Value?> =
+    item(default, key).transform { it.value }
+
+fun <T> Configurable.value(
+    default: T? = null,
+    key: Name? = null,
+    writer: (T) -> Value? = { Value.of(it) },
+    reader: (Value?) -> T
+): ReadWriteProperty<Any?, T> =
+    ConfigurableDelegate(this, key, default?.let { MetaItem.of(it) }).transform(
+        reader = { reader(it.value) },
+        writer = { writer(it)?.let { MetaItem.ValueItem(it) } }
+    )
+
+fun Configurable.string(default: String? = null, key: Name? = null): ReadWriteProperty<Any?, String?> =
+    item(default, key).transform { it.value?.string }
+
+fun Configurable.boolean(default: Boolean? = null, key: Name? = null): ReadWriteProperty<Any?, Boolean?> =
+    item(default, key).transform { it.value?.boolean }
+
+fun Configurable.number(default: Number? = null, key: Name? = null): ReadWriteProperty<Any?, Number?> =
+    item(default, key).transform { it.value?.number }
+
+/* Number delegates*/
+
+fun Configurable.int(default: Int? = null, key: Name? = null): ReadWriteProperty<Any?, Int?> =
+    item(default, key).transform { it.value?.int }
+
+fun Configurable.double(default: Double? = null, key: Name? = null): ReadWriteProperty<Any?, Double?> =
+    item(default, key).transform { it.value?.double }
+
+fun Configurable.long(default: Long? = null, key: Name? = null): ReadWriteProperty<Any?, Long?> =
+    item(default, key).transform { it.value?.long }
+
+fun Configurable.short(default: Short? = null, key: Name? = null): ReadWriteProperty<Any?, Short?> =
+    item(default, key).transform { it.value?.short }
+
+fun Configurable.float(default: Float? = null, key: Name? = null): ReadWriteProperty<Any?, Float?> =
+    item(default, key).transform { it.value?.float }
+
+
+@JvmName("safeString")
+fun Configurable.string(default: String, key: Name? = null): ReadWriteProperty<Any?, String> =
+    item(default, key).transform { it.value!!.string }
+
+@JvmName("safeBoolean")
+fun Configurable.boolean(default: Boolean, key: Name? = null): ReadWriteProperty<Any?, Boolean> =
+    item(default, key).transform { it.value!!.boolean }
+
+@JvmName("safeNumber")
+fun Configurable.number(default: Number, key: Name? = null): ReadWriteProperty<Any?, Number> =
+    item(default, key).transform { it.value!!.number }
+
+/* Lazy initializers for values */
+
+@JvmName("lazyString")
+fun Configurable.string(key: Name? = null, default: () -> String): ReadWriteProperty<Any?, String> =
+    lazyItem(key, default).transform { it.value!!.string }
+
+@JvmName("lazyBoolean")
+fun Configurable.boolean(key: Name? = null, default: () -> Boolean): ReadWriteProperty<Any?, Boolean> =
+    lazyItem(key, default).transform { it.value!!.boolean }
+
+@JvmName("lazyNumber")
+fun Configurable.number(key: Name? = null, default: () -> Number): ReadWriteProperty<Any?, Number> =
+    lazyItem(key, default).transform { it.value!!.number }
+
+/* Safe number delegates*/
+
+@JvmName("safeInt")
+fun Configurable.int(default: Int, key: Name? = null): ReadWriteProperty<Any?, Int> =
+    item(default, key).transform { it.value!!.int }
+
+@JvmName("safeDouble")
+fun Configurable.double(default: Double, key: Name? = null): ReadWriteProperty<Any?, Double> =
+    item(default, key).transform { it.value!!.double }
+
+@JvmName("safeLong")
+fun Configurable.long(default: Long, key: Name? = null): ReadWriteProperty<Any?, Long> =
+    item(default, key).transform { it.value!!.long }
+
+@JvmName("safeShort")
+fun Configurable.short(default: Short, key: Name? = null): ReadWriteProperty<Any?, Short> =
+    item(default, key).transform { it.value!!.short }
+
+@JvmName("safeFloat")
+fun Configurable.float(default: Float, key: Name? = null): ReadWriteProperty<Any?, Float> =
+    item(default, key).transform { it.value!!.float }
+
+/**
+ * Enum delegate
+ */
+inline fun <reified E : Enum<E>> Configurable.enum(default: E, key: Name? = null): ReadWriteProperty<Any?, E?> =
+    item(default, key).transform { it.enum<E>() }
+
+/*
+ * Extra delegates for special cases
+ */
+
+fun Configurable.stringList(vararg strings: String, key: Name? = null): ReadWriteProperty<Any?, List<String>> =
+    item(listOf(*strings), key) {
+        it?.value?.stringList ?: emptyList()
+    }
+
+fun Configurable.numberList(vararg numbers: Number, key: Name? = null): ReadWriteProperty<Any?, List<Number>> =
+    item(listOf(*numbers), key) { item ->
+        item?.value?.list?.map { it.number } ?: emptyList()
+    }
+
+/**
+ * A special delegate for double arrays
+ */
+fun Configurable.doubleArray(vararg doubles: Double, key: Name? = null): ReadWriteProperty<Any?, DoubleArray> =
+    item(doubleArrayOf(*doubles), key) {
+        (it.value as? DoubleArrayValue)?.value
+            ?: it?.value?.list?.map { value -> value.number.toDouble() }?.toDoubleArray()
+            ?: doubleArrayOf()
+    }
+
+
+/* Node delegates */
+
+fun Configurable.nullableConfig(key: Name? = null): ReadWriteProperty<Any?, Config?> =
+    object : ReadWriteProperty<Any?, Config?> {
+        override fun getValue(thisRef: Any?, property: KProperty<*>): Config? {
+            val name = key ?: property.name.asName()
+            return config[name].node
+        }
+
+        override fun setValue(thisRef: Any?, property: KProperty<*>, value: Config?) {
+            val name = key ?: property.name.asName()
+            config[name] = value
+        }
+    }
+
+fun Configurable.config(key: Name? = null, default: Config.() -> Unit = {}): ReadWriteProperty<Any?, Config> =
+    object : ReadWriteProperty<Any?, Config> {
+        override fun getValue(thisRef: Any?, property: KProperty<*>): Config {
+            val name = key ?: property.name.asName()
+            return config[name].node ?: Config().apply(default).also { config[name] = it }
+        }
+
+        override fun setValue(thisRef: Any?, property: KProperty<*>, value: Config) {
+            val name = key ?: property.name.asName()
+            config[name] = value
+        }
+    }
+
+fun <T : Configurable> Configurable.spec(spec: Specification<T>, key: Name? = null): ReadWriteProperty<Any?, T?> =
+    object : ReadWriteProperty<Any?, T?> {
+        override fun getValue(thisRef: Any?, property: KProperty<*>): T? {
+            val name = key ?: property.name.asName()
+            return config[name].node?.let { spec.wrap(it) }
+        }
+
+        override fun setValue(thisRef: Any?, property: KProperty<*>, value: T?) {
+            val name = key ?: property.name.asName()
+            config[name] = value?.config
+        }
+
+    }
+

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

@@ -350,24 +350,6 @@ class MutableNodeDelegate<M : MutableMeta<M>>(
     }
 }
 
-class MutableMorphDelegate<T : Configurable>(
-    val meta: MutableMeta<*>,
-    private val key: Name? = null,
-    private val converter: (Meta) -> T
-) : ReadWriteProperty<Any?, T?> {
-    override fun getValue(thisRef: Any?, property: KProperty<*>): T? {
-        return meta[key ?: property.name.asName()]?.node?.let(converter)
-    }
-
-    override fun setValue(thisRef: Any?, property: KProperty<*>, value: T?) {
-        if (value == null) {
-            meta.remove(key ?: property.name.asName())
-        } else {
-            meta[key ?: property.name.asName()] = value.config
-        }
-    }
-}
-
 class ReadWriteDelegateWrapper<T, R>(
     val delegate: ReadWriteProperty<Any?, T>,
     val reader: (T) -> R,

dataforge-meta/src/commonMain/kotlin/hep/dataforge/values/valueExtensions.kt

@@ -22,6 +22,7 @@ val Value.boolean
 val Value.int get() = number.toInt()
 val Value.double get() = number.toDouble()
 val Value.float get() = number.toFloat()
+val Value.short get() = number.toShort()
 val Value.long get() = number.toLong()
 
 val Value.stringList: List<String> get() = list.map { it.string }

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

@@ -13,14 +13,13 @@ class MetaDelegateTest {
     @Test
     fun delegateTest() {
 
-        class InnerSpec(override val config: Config) : Specific {
+        class InnerSpec : Scheme() {
             var innerValue by string()
         }
 
-        val innerSpec = specification(::InnerSpec)
+        val innerSpec = object : SchemeSpec<InnerSpec>(::InnerSpec){}
 
-        val testObject = object : Specific {
+        val testObject = object : Scheme(Config()) {
-            override val config: Config = Config()
             var myValue by string()
             var safeValue by double(2.2)
             var enumValue by enum(TestEnum.YES)

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

@@ -14,7 +14,7 @@ class MutableMetaTest{
                 "b" put 22
                 "c" put "StringValue"
             }
-        }.toConfig()
+        }.asConfig()
 
         meta.remove("aNode.c")
         assertEquals(meta["aNode.c"], null)

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

@@ -4,19 +4,22 @@ import kotlin.test.Test
 import kotlin.test.assertEquals
 
 
-class StyledTest{
+class SchemeTest{
     @Test
-    fun testSNS(){
+    fun testMetaScheme(){
-        val meta = buildMeta {
+        val styled = buildMeta {
             repeat(10){
                 "b.a[$it]" put {
                     "d" put it
                 }
             }
-        }.seal().withStyle()
+        }.toScheme()
+
+        val meta = styled.toMeta()
+
         assertEquals(10, meta.values().count())
 
-        val bNode = meta["b"].node
+        val bNode = styled.getProperty("b").node
 
         val aNodes = bNode?.getIndexed("a")
 

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

@@ -1,21 +1,26 @@
 package hep.dataforge.meta
 
+import hep.dataforge.names.Name
 import kotlin.test.Test
 import kotlin.test.assertEquals
 
 class SpecificationTest {
-    class TestSpecific(override val config: Config) : Specific {
+    class TestStyled(config: Config, defaultProvider: (Name) -> MetaItem<*>?) :
+        Scheme(config, defaultProvider) {
         var list by numberList(1, 2, 3)
 
-        companion object : Specification<TestSpecific> {
+        companion object : Specification<TestStyled> {
-            override fun wrap(config: Config): TestSpecific = TestSpecific(config)
+            override fun wrap(
+                config: Config,
+                defaultProvider: (Name) -> MetaItem<*>?
+            ): TestStyled = TestStyled(config, defaultProvider)
         }
     }
 
 
     @Test
-    fun testSpecific(){
+    fun testSpecific() {
-        val testObject = TestSpecific {
+        val testObject = TestStyled {
             list = emptyList()
         }
         assertEquals(emptyList(), testObject.list)