Merge MetaConverter and MetaSpec

CHANGELOG.md

@@ -8,6 +8,7 @@
 - Add Meta and MutableMeta delegates for convertable and serializeable
 
 ### Changed
+- Descriptor `children` renamed to `nodes`
 
 ### Deprecated
 - `node(key,converter)` in favor of `serializable` delegate

dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/properties/MetaProperty.kt

@@ -1,11 +1,7 @@
 package space.kscience.dataforge.properties
 
 
-import space.kscience.dataforge.meta.Meta
+import space.kscience.dataforge.meta.*
-import space.kscience.dataforge.meta.ObservableMutableMeta
-import space.kscience.dataforge.meta.transformations.MetaConverter
-import space.kscience.dataforge.meta.transformations.nullableMetaToObject
-import space.kscience.dataforge.meta.transformations.nullableObjectToMeta
 import space.kscience.dataforge.misc.DFExperimental
 import space.kscience.dataforge.names.Name
 import space.kscience.dataforge.names.startsWith
@@ -18,14 +14,14 @@ public class MetaProperty<T : Any>(
 ) : Property<T?> {
 
     override var value: T?
-        get() = converter.nullableMetaToObject(meta[name])
+        get() = converter.readNullable(meta[name])
         set(value) {
-            meta[name] = converter.nullableObjectToMeta(value) ?: Meta.EMPTY
+            meta[name] = converter.convertNullable(value) ?: Meta.EMPTY
         }
 
     override fun onChange(owner: Any?, callback: (T?) -> Unit) {
         meta.onChange(owner) { name ->
-            if (name.startsWith(this@MetaProperty.name)) callback(converter.nullableMetaToObject(this[name]))
+            if (name.startsWith(this@MetaProperty.name)) callback(converter.readNullable(this[name]))
         }
     }
 

dataforge-context/src/jvmTest/kotlin/space/kscience/dataforge/descriptors/TestAutoDescriptors.kt

@@ -3,9 +3,11 @@ package space.kscience.dataforge.descriptors
 import kotlinx.serialization.encodeToString
 import kotlinx.serialization.json.Json
 import org.junit.jupiter.api.Test
-import space.kscience.dataforge.meta.*
+import space.kscience.dataforge.meta.Scheme
+import space.kscience.dataforge.meta.SchemeSpec
 import space.kscience.dataforge.meta.descriptors.MetaDescriptor
-import space.kscience.dataforge.meta.transformations.MetaConverter
+import space.kscience.dataforge.meta.int
+import space.kscience.dataforge.meta.string
 
 private class TestScheme: Scheme(){
 

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

@@ -31,7 +31,7 @@ private fun Meta.toJsonWithIndex(descriptor: MetaDescriptor?, index: String?): J
     val pairs: MutableList<Pair<String, JsonElement>> = items.entries.groupBy {
         it.key.body
     }.mapTo(ArrayList()) { (body, list) ->
-        val childDescriptor = descriptor?.children?.get(body)
+        val childDescriptor = descriptor?.nodes?.get(body)
         if (list.size == 1) {
             val (token, element) = list.first()
                 //do not add an empty element

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

@@ -1,19 +1,19 @@
-package space.kscience.dataforge.meta.transformations
+package space.kscience.dataforge.meta
 
 import kotlinx.serialization.KSerializer
 import kotlinx.serialization.json.Json
 import kotlinx.serialization.json.encodeToJsonElement
 import kotlinx.serialization.serializer
-import space.kscience.dataforge.meta.*
 import space.kscience.dataforge.meta.descriptors.MetaDescriptor
 import space.kscience.dataforge.misc.DFExperimental
 import kotlin.reflect.KType
 import kotlin.reflect.typeOf
 
+
 /**
  * A converter of generic object to and from [Meta]
  */
-public interface MetaConverter<T> {
+public interface MetaConverter<T>: MetaSpec<T> {
 
     /**
      * Runtime type of [T]
@@ -23,32 +23,32 @@ public interface MetaConverter<T> {
     /**
      * A descriptor for resulting meta
      */
-    public val descriptor: MetaDescriptor get() = MetaDescriptor.EMPTY
+    override val descriptor: MetaDescriptor get() = MetaDescriptor.EMPTY
 
     /**
-     * Attempt conversion of [meta] to an object or return null if conversion failed
+     * Attempt conversion of [source] to an object or return null if conversion failed
      */
-    public fun metaToObjectOrNull(meta: Meta): T?
+    override fun readOrNull(source: Meta): T?
 
-    public fun metaToObject(meta: Meta): T =
+    override fun read(source: Meta): T =
-        metaToObjectOrNull(meta) ?: error("Meta $meta could not be interpreted by $this")
+        readOrNull(source) ?: error("Meta $source could not be interpreted by $this")
 
-    public fun objectToMeta(obj: T): Meta
+    public fun convert(obj: T): Meta
 
     public companion object {
 
         public val meta: MetaConverter<Meta> = object : MetaConverter<Meta> {
             override val type: KType = typeOf<Meta>()
 
-            override fun metaToObjectOrNull(meta: Meta): Meta = meta
+            override fun readOrNull(source: Meta): Meta = source
-            override fun objectToMeta(obj: Meta): Meta = obj
+            override fun convert(obj: Meta): Meta = obj
         }
 
         public val value: MetaConverter<Value> = object : MetaConverter<Value> {
             override val type: KType = typeOf<Value>()
 
-            override fun metaToObjectOrNull(meta: Meta): Value? = meta.value
+            override fun readOrNull(source: Meta): Value? = source.value
-            override fun objectToMeta(obj: Value): Meta = Meta(obj)
+            override fun convert(obj: Value): Meta = Meta(obj)
         }
 
         public val string: MetaConverter<String> = object : MetaConverter<String> {
@@ -59,8 +59,8 @@ public interface MetaConverter<T> {
             }
 
 
-            override fun metaToObjectOrNull(meta: Meta): String? = meta.string
+            override fun readOrNull(source: Meta): String? = source.string
-            override fun objectToMeta(obj: String): Meta = Meta(obj.asValue())
+            override fun convert(obj: String): Meta = Meta(obj.asValue())
         }
 
         public val boolean: MetaConverter<Boolean> = object : MetaConverter<Boolean> {
@@ -70,8 +70,8 @@ public interface MetaConverter<T> {
                 valueType(ValueType.BOOLEAN)
             }
 
-            override fun metaToObjectOrNull(meta: Meta): Boolean? = meta.boolean
+            override fun readOrNull(source: Meta): Boolean? = source.boolean
-            override fun objectToMeta(obj: Boolean): Meta = Meta(obj.asValue())
+            override fun convert(obj: Boolean): Meta = Meta(obj.asValue())
         }
 
         public val number: MetaConverter<Number> = object : MetaConverter<Number> {
@@ -81,8 +81,8 @@ public interface MetaConverter<T> {
                 valueType(ValueType.NUMBER)
             }
 
-            override fun metaToObjectOrNull(meta: Meta): Number? = meta.number
+            override fun readOrNull(source: Meta): Number? = source.number
-            override fun objectToMeta(obj: Number): Meta = Meta(obj.asValue())
+            override fun convert(obj: Number): Meta = Meta(obj.asValue())
         }
 
         public val double: MetaConverter<Double> = object : MetaConverter<Double> {
@@ -92,8 +92,8 @@ public interface MetaConverter<T> {
                 valueType(ValueType.NUMBER)
             }
 
-            override fun metaToObjectOrNull(meta: Meta): Double? = meta.double
+            override fun readOrNull(source: Meta): Double? = source.double
-            override fun objectToMeta(obj: Double): Meta = Meta(obj.asValue())
+            override fun convert(obj: Double): Meta = Meta(obj.asValue())
         }
 
         public val float: MetaConverter<Float> = object : MetaConverter<Float> {
@@ -103,8 +103,8 @@ public interface MetaConverter<T> {
                 valueType(ValueType.NUMBER)
             }
 
-            override fun metaToObjectOrNull(meta: Meta): Float? = meta.float
+            override fun readOrNull(source: Meta): Float? = source.float
-            override fun objectToMeta(obj: Float): Meta = Meta(obj.asValue())
+            override fun convert(obj: Float): Meta = Meta(obj.asValue())
         }
 
         public val int: MetaConverter<Int> = object : MetaConverter<Int> {
@@ -114,8 +114,8 @@ public interface MetaConverter<T> {
                 valueType(ValueType.NUMBER)
             }
 
-            override fun metaToObjectOrNull(meta: Meta): Int? = meta.int
+            override fun readOrNull(source: Meta): Int? = source.int
-            override fun objectToMeta(obj: Int): Meta = Meta(obj.asValue())
+            override fun convert(obj: Int): Meta = Meta(obj.asValue())
         }
 
         public val long: MetaConverter<Long> = object : MetaConverter<Long> {
@@ -125,8 +125,8 @@ public interface MetaConverter<T> {
                 valueType(ValueType.NUMBER)
             }
 
-            override fun metaToObjectOrNull(meta: Meta): Long? = meta.long
+            override fun readOrNull(source: Meta): Long? = source.long
-            override fun objectToMeta(obj: Long): Meta = Meta(obj.asValue())
+            override fun convert(obj: Long): Meta = Meta(obj.asValue())
         }
 
         public inline fun <reified E : Enum<E>> enum(): MetaConverter<E> = object : MetaConverter<E> {
@@ -138,9 +138,9 @@ public interface MetaConverter<T> {
             }
 
             @Suppress("USELESS_CAST")
-            override fun metaToObjectOrNull(meta: Meta): E = meta.enum<E>() as? E ?: error("The Item is not a Enum")
+            override fun readOrNull(source: Meta): E = source.enum<E>() as? E ?: error("The Item is not a Enum")
 
-            override fun objectToMeta(obj: E): Meta = Meta(obj.asValue())
+            override fun convert(obj: E): Meta = Meta(obj.asValue())
         }
 
         public fun <T> valueList(
@@ -153,9 +153,9 @@ public interface MetaConverter<T> {
                 valueType(ValueType.LIST)
             }
 
-            override fun metaToObjectOrNull(meta: Meta): List<T>? = meta.value?.list?.map(reader)
+            override fun readOrNull(source: Meta): List<T>? = source.value?.list?.map(reader)
 
-            override fun objectToMeta(obj: List<T>): Meta = Meta(obj.map(writer).asValue())
+            override fun convert(obj: List<T>): Meta = Meta(obj.map(writer).asValue())
         }
 
         /**
@@ -168,12 +168,12 @@ public interface MetaConverter<T> {
             override val type: KType = typeOf<T>()
             private val serializer: KSerializer<T> = serializer()
 
-            override fun metaToObjectOrNull(meta: Meta): T? {
+            override fun readOrNull(source: Meta): T? {
-                val json = meta.toJson(descriptor)
+                val json = source.toJson(descriptor)
                 return Json.decodeFromJsonElement(serializer, json)
             }
 
-            override fun objectToMeta(obj: T): Meta {
+            override fun convert(obj: T): Meta {
                 val json = Json.encodeToJsonElement(obj)
                 return json.toMeta(descriptor)
             }
@@ -183,7 +183,7 @@ public interface MetaConverter<T> {
     }
 }
 
-public fun <T : Any> MetaConverter<T>.nullableMetaToObject(item: Meta?): T? = item?.let { metaToObject(it) }
+public fun <T : Any> MetaConverter<T>.readNullable(item: Meta?): T? = item?.let { read(it) }
-public fun <T : Any> MetaConverter<T>.nullableObjectToMeta(obj: T?): Meta? = obj?.let { objectToMeta(it) }
+public fun <T : Any> MetaConverter<T>.convertNullable(obj: T?): Meta? = obj?.let { convert(it) }
 
-public fun <T> MetaConverter<T>.valueToObject(value: Value): T? = metaToObject(Meta(value))
+public fun <T> MetaConverter<T>.readValue(value: Value): T? = read(Meta(value))

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

@@ -1,7 +1,6 @@
 package space.kscience.dataforge.meta
 
 import space.kscience.dataforge.meta.descriptors.MetaDescriptor
-import space.kscience.dataforge.meta.transformations.MetaConverter
 import space.kscience.dataforge.misc.DFExperimental
 import space.kscience.dataforge.names.Name
 import space.kscience.dataforge.names.asName
@@ -20,7 +19,7 @@ public fun <T> MetaProvider.convertable(
     converter: MetaConverter<T>,
     key: Name? = null,
 ): ReadOnlyProperty<Any?, T?> = ReadOnlyProperty { _, property ->
-    get(key ?: property.name.asName())?.let { converter.metaToObject(it) }
+    get(key ?: property.name.asName())?.let { converter.read(it) }
 }
 
 /**
@@ -46,7 +45,7 @@ public fun <T> Meta.listOfConvertable(
     key: Name? = null,
 ): ReadOnlyProperty<Any?, List<T>> = ReadOnlyProperty{_, property ->
     val name = key ?: property.name.asName()
-    getIndexed(name).values.map { converter.metaToObject(it) }
+    getIndexed(name).values.map { converter.read(it) }
 }
 
 @DFExperimental

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

@@ -0,0 +1,18 @@
+package space.kscience.dataforge.meta
+
+import space.kscience.dataforge.meta.descriptors.Described
+
+public interface MetaSpec<out T> : Described {
+
+    /**
+     * Read the source meta into an object and return null if Meta could not be interpreted as a target type
+     */
+    public fun readOrNull(source: Meta): T?
+
+    /**
+     * Read generic read-only meta with this [MetaSpec] producing instance of the desired type.
+     * Throws an error if conversion could not be done.
+     */
+    public fun read(source: Meta): T = readOrNull(source) ?: error("Meta $source could not be interpreted by $this")
+}
+

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

@@ -1,6 +1,5 @@
-package space.kscience.dataforge.meta.transformations
+package space.kscience.dataforge.meta
 
-import space.kscience.dataforge.meta.*
 import space.kscience.dataforge.misc.DFExperimental
 import space.kscience.dataforge.names.Name
 import kotlin.jvm.JvmInline

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

@@ -1,7 +1,6 @@
 package space.kscience.dataforge.meta
 
 import space.kscience.dataforge.meta.descriptors.MetaDescriptor
-import space.kscience.dataforge.meta.transformations.MetaConverter
 import space.kscience.dataforge.misc.DFExperimental
 import space.kscience.dataforge.names.Name
 import space.kscience.dataforge.names.asName
@@ -33,12 +32,12 @@ public fun <T> MutableMetaProvider.convertable(
     object : ReadWriteProperty<Any?, T?> {
         override fun getValue(thisRef: Any?, property: KProperty<*>): T? {
             val name = key ?: property.name.asName()
-            return get(name)?.let { converter.metaToObject(it) }
+            return get(name)?.let { converter.read(it) }
         }
 
         override fun setValue(thisRef: Any?, property: KProperty<*>, value: T?) {
             val name = key ?: property.name.asName()
-            set(name, value?.let { converter.objectToMeta(it) })
+            set(name, value?.let { converter.convert(it) })
         }
     }
 
@@ -66,12 +65,12 @@ public fun <T> MutableMeta.listOfConvertable(
 ): ReadWriteProperty<Any?, List<T>> = object : ReadWriteProperty<Any?, List<T>> {
     override fun getValue(thisRef: Any?, property: KProperty<*>): List<T> {
         val name = key ?: property.name.asName()
-        return getIndexed(name).values.map { converter.metaToObject(it) }
+        return getIndexed(name).values.map { converter.read(it) }
     }
 
     override fun setValue(thisRef: Any?, property: KProperty<*>, value: List<T>) {
         val name = key ?: property.name.asName()
-        setIndexed(name, value.map { converter.objectToMeta(it) })
+        setIndexed(name, value.map { converter.convert(it) })
     }
 }
 

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

@@ -7,9 +7,11 @@ import space.kscience.dataforge.meta.descriptors.validate
 import space.kscience.dataforge.misc.DFExperimental
 import space.kscience.dataforge.misc.ThreadSafe
 import space.kscience.dataforge.names.*
+import kotlin.properties.ReadWriteProperty
+import kotlin.reflect.KProperty
 
 /**
- * A base for delegate-based or descriptor-based scheme. [Scheme] has an empty constructor to simplify usage from [Specification].
+ * A base for delegate-based or descriptor-based scheme. [Scheme] has an empty constructor to simplify usage from [MetaSpec].
  * Default item provider and [MetaDescriptor] are optional
  */
 public open class Scheme : Described, MetaRepr, MutableMetaProvider, Configurable {
@@ -165,23 +167,124 @@ public inline fun <T : Scheme> T.copy(spec: SchemeSpec<T>, block: T.() -> Unit =
  */
 public open class SchemeSpec<out T : Scheme>(
     private val builder: () -> T,
-) : Specification<T> {
+) : MetaSpec<T> {
 
     override val descriptor: MetaDescriptor? get() = null
 
-    override fun read(source: Meta): T = builder().also {
+    override fun readOrNull(source: Meta): T = builder().also {
         it.initialize(MutableMeta(), source, descriptor)
     }
 
-    override fun write(target: MutableMeta): T = empty().also {
+    public fun write(target: MutableMeta): T = empty().also {
         it.initialize(target, Meta.EMPTY, descriptor)
     }
 
-    override fun empty(): T = builder().also {
+    /**
+     * Generate an empty object
+     */
+    public fun empty(): T = builder().also {
         it.initialize(MutableMeta(), Meta.EMPTY, descriptor)
     }
 
-    @Suppress("OVERRIDE_BY_INLINE")
+    /**
-    final override inline operator fun invoke(action: T.() -> Unit): T = empty().apply(action)
+     * A convenience method to use specifications in builders
+     */
+    public inline operator fun invoke(action: T.() -> Unit): T = empty().apply(action)
 
 }
+
+
+
+/**
+ * Update a [MutableMeta] using given specification
+ */
+public fun <T : Scheme> MutableMeta.updateWith(
+    spec: SchemeSpec<T>,
+    action: T.() -> Unit,
+): T = spec.write(this).apply(action)
+
+
+/**
+ * Update configuration using given specification
+ */
+public fun <T : Scheme> Configurable.updateWith(
+    spec: SchemeSpec<T>,
+    action: T.() -> Unit,
+): T = spec.write(meta).apply(action)
+
+
+/**
+ * A delegate that uses a [MetaSpec] to wrap a child of this provider
+ */
+public fun <T : Scheme> MutableMeta.scheme(
+    spec: SchemeSpec<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 spec.write(getOrCreate(name))
+    }
+
+    override fun setValue(thisRef: Any?, property: KProperty<*>, value: T) {
+        val name = key ?: property.name.asName()
+        set(name, value.toMeta())
+    }
+}
+
+public fun <T : Scheme> Scheme.scheme(
+    spec: SchemeSpec<T>,
+    key: Name? = null,
+): ReadWriteProperty<Any?, T> = meta.scheme(spec, key)
+
+/**
+ * A delegate that uses a [MetaSpec] to wrap a child of this provider.
+ * Returns null if meta with given name does not exist.
+ */
+public fun <T : Scheme> MutableMeta.schemeOrNull(
+    spec: SchemeSpec<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 if (get(name) == null) null else spec.write(getOrCreate(name))
+    }
+
+    override fun setValue(thisRef: Any?, property: KProperty<*>, value: T?) {
+        val name = key ?: property.name.asName()
+        if (value == null) remove(name)
+        else set(name, value.toMeta())
+    }
+}
+
+public fun <T : Scheme> Scheme.schemeOrNull(
+    spec: SchemeSpec<T>,
+    key: Name? = null,
+): ReadWriteProperty<Any?, T?> = meta.schemeOrNull(spec, key)
+
+/**
+ * A delegate that uses a [MetaSpec] to wrap a list of child providers.
+ * If children are mutable, the changes in list elements are reflected on them.
+ * The list is a snapshot of children state, so change in structure is not reflected on its composition.
+ */
+@DFExperimental
+public fun <T : Scheme> MutableMeta.listOfScheme(
+    spec: SchemeSpec<T>,
+    key: Name? = null,
+): ReadWriteProperty<Any?, List<T>> = object : ReadWriteProperty<Any?, List<T>> {
+    override fun getValue(thisRef: Any?, property: KProperty<*>): List<T> {
+        val name = key ?: property.name.asName()
+        return getIndexed(name).values.map { spec.write(it as MutableMeta) }
+    }
+
+    override fun setValue(thisRef: Any?, property: KProperty<*>, value: List<T>) {
+        val name = key ?: property.name.asName()
+        setIndexed(name, value.map { it.toMeta() })
+    }
+}
+
+
+@DFExperimental
+public fun <T : Scheme> Scheme.listOfScheme(
+    spec: SchemeSpec<T>,
+    key: Name? = null,
+): ReadWriteProperty<Any?, List<T>> = meta.listOfScheme(spec, key)

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

@@ -1,137 +0,0 @@
-package space.kscience.dataforge.meta
-
-import space.kscience.dataforge.meta.descriptors.Described
-import space.kscience.dataforge.misc.DFExperimental
-import space.kscience.dataforge.names.Name
-import space.kscience.dataforge.names.asName
-import kotlin.properties.ReadWriteProperty
-import kotlin.reflect.KProperty
-
-public interface ReadOnlySpecification<out T : Any> : Described {
-
-    /**
-     * Read generic read-only meta with this [Specification] producing instance of desired type.
-     * The source is not mutated even if it is in theory mutable
-     */
-    public fun read(source: Meta): T
-
-    /**
-     * Generate an empty object
-     */
-    public fun empty(): T
-
-    /**
-     * A convenience method to use specifications in builders
-     */
-    public operator fun invoke(action: T.() -> Unit): T = empty().apply(action)
-}
-
-
-/**
- * Allows to apply custom configuration in a type safe way to simple untyped configuration.
- * By convention [Scheme] companion should inherit this class
- *
- */
-public interface Specification<out T : Any> : ReadOnlySpecification<T> {
-    /**
-     * Wrap [MutableMeta], using it as inner storage (changes to [Specification] are reflected on [MutableMeta]
-     */
-    public fun write(target: MutableMeta): T
-}
-
-/**
- * Update a [MutableMeta] using given specification
- */
-public fun <T : Any> MutableMeta.updateWith(
-    spec: Specification<T>,
-    action: T.() -> Unit,
-): T = spec.write(this).apply(action)
-
-
-/**
- * Update configuration using given specification
- */
-public fun <T : Any> Configurable.updateWith(
-    spec: Specification<T>,
-    action: T.() -> Unit,
-): T = spec.write(meta).apply(action)
-
-//
-//public fun  <M : MutableTypedMeta<M>> MutableMeta.withSpec(spec: Specification<M>): M? =
-//    spec.write(it)
-
-/**
- * A delegate that uses a [Specification] to wrap a child of this provider
- */
-public fun <T : Scheme> MutableMeta.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 spec.write(getOrCreate(name))
-    }
-
-    override fun setValue(thisRef: Any?, property: KProperty<*>, value: T) {
-        val name = key ?: property.name.asName()
-        set(name, value.toMeta())
-    }
-}
-
-public fun <T : Scheme> Scheme.spec(
-    spec: Specification<T>,
-    key: Name? = null,
-): ReadWriteProperty<Any?, T> = meta.spec(spec, key)
-
-/**
- * A delegate that uses a [Specification] to wrap a child of this provider.
- * Returns null if meta with given name does not exist.
- */
-public fun <T : Scheme> MutableMeta.specOrNull(
-    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 if (get(name) == null) null else spec.write(getOrCreate(name))
-    }
-
-    override fun setValue(thisRef: Any?, property: KProperty<*>, value: T?) {
-        val name = key ?: property.name.asName()
-        if (value == null) remove(name)
-        else set(name, value.toMeta())
-    }
-}
-
-public fun <T : Scheme> Scheme.specOrNull(
-    spec: Specification<T>,
-    key: Name? = null,
-): ReadWriteProperty<Any?, T?> = meta.specOrNull(spec, key)
-
-/**
- * A delegate that uses a [Specification] to wrap a list of child providers.
- * If children are mutable, the changes in list elements are reflected on them.
- * The list is a snapshot of children state, so change in structure is not reflected on its composition.
- */
-@DFExperimental
-public fun <T : Scheme> MutableMeta.listOfSpec(
-    spec: Specification<T>,
-    key: Name? = null,
-): ReadWriteProperty<Any?, List<T>> = object : ReadWriteProperty<Any?, List<T>> {
-    override fun getValue(thisRef: Any?, property: KProperty<*>): List<T> {
-        val name = key ?: property.name.asName()
-        return getIndexed(name).values.map { spec.write(it as MutableMeta) }
-    }
-
-    override fun setValue(thisRef: Any?, property: KProperty<*>, value: List<T>) {
-        val name = key ?: property.name.asName()
-        setIndexed(name, value.map { it.toMeta() })
-    }
-}
-
-
-@DFExperimental
-public fun <T : Scheme> Scheme.listOfSpec(
-    spec: Specification<T>,
-    key: Name? = null,
-): ReadWriteProperty<Any?, List<T>> = meta.listOfSpec(spec, key)

dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/descriptors/MetaDescriptor.kt

@@ -27,7 +27,7 @@ public enum class ValueRestriction {
 /**
  * The descriptor for a meta
  * @param description description text
- * @param children child descriptors for this node
+ * @param nodes child descriptors for this node
  * @param multiple True if same name siblings with this name are allowed
  * @param valueRestriction The requirements for node content
  * @param valueTypes list of allowed types for [Meta.value], null if all values are allowed.
@@ -39,7 +39,7 @@ public enum class ValueRestriction {
 @Serializable
 public data class MetaDescriptor(
     public val description: String? = null,
-    public val children: Map<String, MetaDescriptor> = emptyMap(),
+    public val nodes: Map<String, MetaDescriptor> = emptyMap(),
     public val multiple: Boolean = false,
     public val valueRestriction: ValueRestriction = ValueRestriction.NONE,
     public val valueTypes: List<ValueType>? = null,
@@ -47,6 +47,9 @@ public data class MetaDescriptor(
     public val defaultValue: Value? = null,
     public val attributes: Meta = Meta.EMPTY,
 ) {
+    @Deprecated("Replace by nodes", ReplaceWith("nodes"))
+    public val children: Map<String, MetaDescriptor> get() = nodes
+
     /**
      * A node constructed of default values for this descriptor and its children
      */
@@ -55,7 +58,7 @@ public data class MetaDescriptor(
             defaultValue?.let { defaultValue ->
                 this.value = defaultValue
             }
-            children.forEach { (key, descriptor) ->
+            nodes.forEach { (key, descriptor) ->
                 set(key, descriptor.defaultNode)
             }
         }
@@ -67,13 +70,13 @@ public data class MetaDescriptor(
     }
 }
 
-public val MetaDescriptor.required: Boolean get() = valueRestriction == ValueRestriction.REQUIRED || children.values.any { required }
+public val MetaDescriptor.required: Boolean get() = valueRestriction == ValueRestriction.REQUIRED || nodes.values.any { required }
 
 public val MetaDescriptor.allowedValues: List<Value>? get() = attributes[MetaDescriptor.ALLOWED_VALUES_KEY]?.value?.list
 
 public operator fun MetaDescriptor.get(name: Name): MetaDescriptor? = when (name.length) {
     0 -> this
-    1 -> children[name.firstOrNull()!!.toString()]
+    1 -> nodes[name.firstOrNull()!!.toString()]
     else -> get(name.firstOrNull()!!.asName())?.get(name.cutFirst())
 }
 
@@ -95,7 +98,7 @@ public fun MetaDescriptor.validate(item: Meta?): Boolean {
     if (item == null) return !required
     if (!validate(item.value)) return false
 
-    children.forEach { (key, childDescriptor) ->
+    nodes.forEach { (key, childDescriptor) ->
         if (!childDescriptor.validate(item[key])) return false
     }
     return true

dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/descriptors/MetaDescriptorBuilder.kt

@@ -80,7 +80,7 @@ public class MetaDescriptorBuilder @PublishedApi internal constructor() {
 
     public fun from(descriptor: MetaDescriptor) {
         description = descriptor.description
-        children.putAll(descriptor.children.mapValues { it.value.toBuilder() })
+        children.putAll(descriptor.nodes.mapValues { it.value.toBuilder() })
         multiple = descriptor.multiple
         valueRestriction = descriptor.valueRestriction
         valueTypes = descriptor.valueTypes
@@ -92,7 +92,7 @@ public class MetaDescriptorBuilder @PublishedApi internal constructor() {
     @PublishedApi
     internal fun build(): MetaDescriptor = MetaDescriptor(
         description = description,
-        children = children.mapValues { it.value.build() },
+        nodes = children.mapValues { it.value.build() },
         multiple = multiple,
         valueRestriction = valueRestriction,
         valueTypes = valueTypes,
@@ -143,7 +143,7 @@ public fun MetaDescriptorBuilder.required() {
 
 private fun MetaDescriptor.toBuilder(): MetaDescriptorBuilder = MetaDescriptorBuilder().apply {
     description = this@toBuilder.description
-    children = this@toBuilder.children.mapValuesTo(LinkedHashMap()) { it.value.toBuilder() }
+    children = this@toBuilder.nodes.mapValuesTo(LinkedHashMap()) { it.value.toBuilder() }
     multiple = this@toBuilder.multiple
     valueRestriction = this@toBuilder.valueRestriction
     valueTypes = this@toBuilder.valueTypes

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

@@ -20,7 +20,7 @@ class MetaDelegateTest {
         var myValue by string()
         var safeValue by double(2.2)
         var enumValue by enum(TestEnum.YES)
-        var inner by spec(InnerScheme)
+        var inner by scheme(InnerScheme)
 
         companion object : SchemeSpec<TestScheme>(::TestScheme)
     }

dataforge-workspace/src/commonMain/kotlin/space/kscience/dataforge/workspace/Task.kt

@@ -6,7 +6,7 @@ import space.kscience.dataforge.data.DataTree
 import space.kscience.dataforge.data.GoalExecutionRestriction
 import space.kscience.dataforge.meta.Meta
 import space.kscience.dataforge.meta.MetaRepr
-import space.kscience.dataforge.meta.Specification
+import space.kscience.dataforge.meta.MetaSpec
 import space.kscience.dataforge.meta.descriptors.Described
 import space.kscience.dataforge.meta.descriptors.MetaDescriptor
 import space.kscience.dataforge.misc.DfType
@@ -43,10 +43,10 @@ public interface Task<out T : Any> : Described {
 }
 
 /**
- * A [Task] with [Specification] for wrapping and unwrapping task configuration
+ * A [Task] with [MetaSpec] for wrapping and unwrapping task configuration
  */
 public interface TaskWithSpec<out T : Any, C : Any> : Task<T> {
-    public val spec: Specification<C>
+    public val spec: MetaSpec<C>
     override val descriptor: MetaDescriptor? get() = spec.descriptor
 
     public suspend fun execute(workspace: Workspace, taskName: Name, configuration: C): TaskResult<T>
@@ -55,11 +55,11 @@ public interface TaskWithSpec<out T : Any, C : Any> : Task<T> {
         execute(workspace, taskName, spec.read(taskMeta))
 }
 
-public suspend fun <T : Any, C : Any> TaskWithSpec<T, C>.execute(
+//public suspend fun <T : Any, C : Scheme> TaskWithSpec<T, C>.execute(
-    workspace: Workspace,
+//    workspace: Workspace,
-    taskName: Name,
+//    taskName: Name,
-    block: C.() -> Unit = {},
+//    block: C.() -> Unit = {},
-): TaskResult<T> = execute(workspace, taskName, spec(block))
+//): TaskResult<T> = execute(workspace, taskName, spec(block))
 
 public class TaskResultBuilder<in T : Any>(
     public val workspace: Workspace,
@@ -76,7 +76,6 @@ public class TaskResultBuilder<in T : Any>(
  * @param descriptor of meta accepted by this task
  * @param builder for resulting data set
  */
-@Suppress("FunctionName")
 public fun <T : Any> Task(
     resultType: KType,
     descriptor: MetaDescriptor? = null,
@@ -98,7 +97,6 @@ public fun <T : Any> Task(
     }
 }
 
-@Suppress("FunctionName")
 public inline fun <reified T : Any> Task(
     descriptor: MetaDescriptor? = null,
     noinline builder: suspend TaskResultBuilder<T>.() -> Unit,
@@ -116,10 +114,10 @@ public inline fun <reified T : Any> Task(
 @Suppress("FunctionName")
 public fun <T : Any, C : MetaRepr> Task(
     resultType: KType,
-    specification: Specification<C>,
+    specification: MetaSpec<C>,
     builder: suspend TaskResultBuilder<T>.(C) -> Unit,
 ): TaskWithSpec<T, C> = object : TaskWithSpec<T, C> {
-    override val spec: Specification<C> = specification
+    override val spec: MetaSpec<C> = specification
 
     override suspend fun execute(
         workspace: Workspace,
@@ -135,8 +133,7 @@ public fun <T : Any, C : MetaRepr> Task(
     }
 }
 
-@Suppress("FunctionName")
 public inline fun <reified T : Any, C : MetaRepr> Task(
-    specification: Specification<C>,
+    specification: MetaSpec<C>,
     noinline builder: suspend TaskResultBuilder<T>.(C) -> Unit,
 ): Task<T> = Task(typeOf<T>(), specification, builder)

dataforge-workspace/src/commonMain/kotlin/space/kscience/dataforge/workspace/WorkspaceBuilder.kt

@@ -7,8 +7,8 @@ import space.kscience.dataforge.context.Global
 import space.kscience.dataforge.data.*
 import space.kscience.dataforge.meta.Meta
 import space.kscience.dataforge.meta.MetaRepr
+import space.kscience.dataforge.meta.MetaSpec
 import space.kscience.dataforge.meta.MutableMeta
-import space.kscience.dataforge.meta.Specification
 import space.kscience.dataforge.meta.descriptors.MetaDescriptor
 import space.kscience.dataforge.meta.descriptors.MetaDescriptorBuilder
 import space.kscience.dataforge.misc.DFBuilder
@@ -68,7 +68,7 @@ public inline fun <reified T : Any> TaskContainer.task(
 }
 
 public inline fun <reified T : Any, C : MetaRepr> TaskContainer.task(
-    specification: Specification<C>,
+    specification: MetaSpec<C>,
     noinline builder: suspend TaskResultBuilder<T>.(C) -> Unit,
 ): PropertyDelegateProvider<Any?, ReadOnlyProperty<Any?, TaskReference<T>>> = PropertyDelegateProvider { _, property ->
     val taskName = Name.parse(property.name)