Experimental listOfSpec delegate.

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## [Unreleased]
 ### Added
+- Experimental `listOfSpec` delegate.
 
 ### Changed
 - **API breaking** Descriptor no has a member property `defaultValue` instead of `defaultItem()` extension. It cahces default value state on the first call. It is done because computing default on each call is too expensive.

dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/ContextBuilder.kt

@@ -67,7 +67,7 @@ public class ContextBuilder internal constructor(
         return Context(contextName, parent, meta.seal()).apply {
             factories.forEach { (factory, meta) ->
                 @Suppress("DEPRECATION")
-                plugins.load(factory, meta)
+                plugins.fetch(factory, meta)
             }
         }
     }
@@ -85,7 +85,7 @@ public fun Context.withEnv(block: ContextBuilder.() -> Unit): Context {
     }
 
     val builder = ContextBuilder(this, name + "env", properties).apply(block)
-    val requiresFork = builder.factories.any { (factory, meta) ->
+    val requiresFork = builder.factories.values.any { (factory, meta) ->
         !contains(factory, meta)
     } || ((properties as Meta) == builder.meta)
     return if (requiresFork) builder.build() else this

dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/PluginManager.kt

@@ -83,7 +83,6 @@ public class PluginManager(override val context: Context) : ContextAware, Iterab
      * @param plugin
      * @return
      */
-    @Deprecated("Use immutable contexts instead")
     private fun <T : Plugin> load(plugin: T): T {
         if (get(plugin::class, plugin.tag, recursive = false) != null) {
             error("Plugin with tag ${plugin.tag} already exists in ${context.name}")
@@ -99,12 +98,6 @@ public class PluginManager(override val context: Context) : ContextAware, Iterab
         }
     }
 
-    /**
-     * Load a plugin using its factory
-     */
-    @Deprecated("Use immutable contexts instead")
-    internal fun <T : Plugin> load(factory: PluginFactory<T>, meta: Meta = Meta.EMPTY): T =
-        load(factory(meta, context))
 
     /**
      * Remove a plugin from [PluginManager]

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

@@ -68,7 +68,7 @@ public fun ItemProvider.getIndexed(name: Name): Map<String?, MetaItem> {
     }
 }
 
-public fun ItemProvider.getIndexed(name: String): Map<String?, MetaItem> = this@getIndexed.getIndexed(name.toName())
+public fun ItemProvider.getIndexed(name: String): Map<String?, MetaItem> = getIndexed(name.toName())
 
 /**
  * Return a provider referencing a child node

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

@@ -1,6 +1,8 @@
 package space.kscience.dataforge.meta
 
 import kotlinx.serialization.Serializable
+import space.kscience.dataforge.names.Name
+import space.kscience.dataforge.names.isEmpty
 import space.kscience.dataforge.values.*
 
 /**
@@ -9,7 +11,7 @@ import space.kscience.dataforge.values.*
  * * a [MetaItemNode] (node)
  */
 @Serializable(MetaItemSerializer::class)
-public sealed class TypedMetaItem<out M : Meta>() {
+public sealed class TypedMetaItem<out M : Meta> : ItemProvider {
 
     abstract override fun equals(other: Any?): Boolean
 
@@ -32,6 +34,8 @@ public typealias MetaItem = TypedMetaItem<*>
 
 @Serializable(MetaItemSerializer::class)
 public class MetaItemValue(public val value: Value) : TypedMetaItem<Nothing>() {
+    override fun getItem(name: Name): MetaItem? = if (name.isEmpty()) this else null
+
     override fun toString(): String = value.toString()
 
     override fun equals(other: Any?): Boolean {
@@ -45,6 +49,8 @@ public class MetaItemValue(public val value: Value) : TypedMetaItem<Nothing>() {
 
 @Serializable(MetaItemSerializer::class)
 public class MetaItemNode<M : Meta>(public val node: M) : TypedMetaItem<M>() {
+    override fun getItem(name: Name): MetaItem? = if (name.isEmpty()) this else node.getItem(name)
+
     //Fixing serializer for node could cause class cast problems, but it should not since Meta descendants are not serializable
     override fun toString(): String = node.toString()
 

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

@@ -96,6 +96,8 @@ public fun MutableItemProvider.getChild(childName: Name): MutableItemProvider {
 
 public fun MutableItemProvider.getChild(childName: String): MutableItemProvider = getChild(childName.toName())
 
+
+
 /**
  * Update existing mutable node with another node. The rules are following:
  *  * value replaces anything

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

@@ -1,5 +1,6 @@
 package space.kscience.dataforge.meta
 
+import space.kscience.dataforge.misc.DFExperimental
 import space.kscience.dataforge.names.Name
 import space.kscience.dataforge.names.asName
 import kotlin.properties.ReadWriteProperty
@@ -57,6 +58,9 @@ public fun <C : MutableItemProvider, S : Specification<C>> Configurable.update(
 public fun <T : MutableItemProvider> TypedMetaItem<MutableMeta<*>>.withSpec(spec: Specification<T>): T? =
     node?.let { spec.write(it) }
 
+/**
+ * A delegate that uses a [Specification] to wrap a child of this provider
+ */
 public fun <T : Scheme> MutableItemProvider.spec(
     spec: Specification<T>,
     key: Name? = null,
@@ -71,3 +75,32 @@ public fun <T : Scheme> MutableItemProvider.spec(
         set(name, value.toMeta().asMetaItem())
     }
 }
+
+/**
+ * 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> MutableItemProvider.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).map {
+            when (val value = it.value) {
+                is MetaItemNode<*> -> when (value.node) {
+                    is MutableItemProvider -> spec.write(value.node)
+                    else -> spec.read(value.node)
+                }
+                is MetaItemValue -> spec.read(value)
+            }
+        }
+    }
+
+    override fun setValue(thisRef: Any?, property: KProperty<*>, value: List<T>) {
+        val name = key ?: property.name.asName()
+        setIndexed(name, value.map { it.toMeta() })
+    }
+}