Delegates for mutable and immutable meta

settings.gradle

@@ -4,8 +4,18 @@ pluginManagement {
             if (requested.id.id == "kotlin-platform-common") {
                 useModule("org.jetbrains.kotlin:kotlin-gradle-plugin:${requested.version}")
             }
+
+            if (requested.id.id == "kotlin-platform-jvm") {
+                useModule("org.jetbrains.kotlin:kotlin-gradle-plugin:${requested.version}")
+            }
+
+            if (requested.id.id == "kotlin-platform-js") {
+                useModule("org.jetbrains.kotlin:kotlin-gradle-plugin:${requested.version}")
+            }
         }
     }
 }
 rootProject.name = 'dataforge-meta'
 
+include ":dataforge-meta-jvm"
+include ":dataforge-meta-js"

src/main/kotlin/hep/dataforge/meta/Configuration.kt

@@ -2,7 +2,11 @@ package hep.dataforge.meta
 
 //TODO add validator to configuration
 
-class Configuration: MutableMetaNode<Configuration>() {
+/**
+ * Mutable meta representing object state
+ */
+class Configuration : MutableMetaNode<Configuration>() {
+
     /**
      * Attach configuration node instead of creating one
      */
@@ -20,4 +24,21 @@ class Configuration: MutableMetaNode<Configuration>() {
     }
 
     override fun empty(): Configuration = Configuration()
-}
+
+    /**
+     * Universal set method
+     */
+    operator fun set(key: String, value: Any?) {
+        when (value) {
+            null -> remove(key)
+            is Meta -> set(key, value)
+            else -> set(key, Value.of(value))
+        }
+    }
+}
+
+interface Configurable {
+    val config: Configuration
+}
+
+open class SimpleConfigurable(override val config:Configuration): Configurable

src/main/kotlin/hep/dataforge/meta/Delegates.kt

@@ -0,0 +1,221 @@
+package hep.dataforge.meta
+
+import kotlin.jvm.JvmName
+import kotlin.properties.ReadOnlyProperty
+import kotlin.properties.ReadWriteProperty
+import kotlin.reflect.KProperty
+
+/* Meta delegates */
+
+class ValueDelegate(private val key: String? = null, private val default: Value? = null) : ReadOnlyProperty<Metoid, Value?> {
+    override fun getValue(thisRef: Metoid, property: KProperty<*>): Value? {
+        return thisRef.meta[key ?: property.name]?.value ?: default
+    }
+}
+
+class StringDelegate(private val key: String? = null, private val default: String? = null) : ReadOnlyProperty<Metoid, String?> {
+    override fun getValue(thisRef: Metoid, property: KProperty<*>): String? {
+        return thisRef.meta[key ?: property.name]?.string ?: default
+    }
+}
+
+class BooleanDelegate(private val key: String? = null, private val default: Boolean? = null) : ReadOnlyProperty<Metoid, Boolean?> {
+    override fun getValue(thisRef: Metoid, property: KProperty<*>): Boolean? {
+        return thisRef.meta[key ?: property.name]?.boolean ?: default
+    }
+}
+
+class NumberDelegate(private val key: String? = null, private val default: Number? = null) : ReadOnlyProperty<Metoid, Number?> {
+    override fun getValue(thisRef: Metoid, property: KProperty<*>): Number? {
+        return thisRef.meta[key ?: property.name]?.number ?: default
+    }
+}
+
+//Delegates with non-null values
+
+class SafeStringDelegate(private val key: String? = null, private val default: String) : ReadOnlyProperty<Metoid, String> {
+    override fun getValue(thisRef: Metoid, property: KProperty<*>): String {
+        return thisRef.meta[key ?: property.name]?.string ?: default
+    }
+}
+
+class SafeBooleanDelegate(private val key: String? = null, private val default: Boolean) : ReadOnlyProperty<Metoid, Boolean> {
+    override fun getValue(thisRef: Metoid, property: KProperty<*>): Boolean {
+        return thisRef.meta[key ?: property.name]?.boolean ?: default
+    }
+}
+
+class SafeNumberDelegate(private val key: String? = null, private val default: Number) : ReadOnlyProperty<Metoid, Number> {
+    override fun getValue(thisRef: Metoid, property: KProperty<*>): Number {
+        return thisRef.meta[key ?: property.name]?.number ?: default
+    }
+}
+
+class SafeEnumDelegate<E : Enum<E>>(private val key: String? = null, private val default: E, private val resolver: (String) -> E) : ReadOnlyProperty<Metoid, E> {
+    override fun getValue(thisRef: Metoid, property: KProperty<*>): E {
+        return (thisRef.meta[key ?: property.name]?.string)?.let { resolver(it) } ?: default
+    }
+}
+
+//Child node delegate
+
+class ChildDelegate<T>(private val key: String? = null, private val converter: (Meta) -> T) : ReadOnlyProperty<Metoid, T?> {
+    override fun getValue(thisRef: Metoid, property: KProperty<*>): T? {
+        return thisRef.meta[key ?: property.name]?.node?.let { converter(it)}
+    }
+}
+
+//Read-only delegates
+
+/**
+ * A property delegate that uses custom key
+ */
+fun Metoid.value(default: Value = Null, key: String? = null) = ValueDelegate(key, default)
+
+fun Metoid.string(default: String? = null, key: String? = null) = StringDelegate(key, default)
+
+fun Metoid.boolean(default: Boolean? = null, key: String? = null) = BooleanDelegate(key, default)
+
+fun Metoid.number(default: Number? = null, key: String? = null) = NumberDelegate(key, default)
+
+fun Metoid.child(key: String? = null) = ChildDelegate(key) { it }
+
+fun <T : Metoid> Metoid.child(key: String? = null, converter: (Meta) -> T) = ChildDelegate(key, converter)
+
+@JvmName("safeString")
+fun Metoid.string(default: String, key: String? = null) = SafeStringDelegate(key, default)
+
+@JvmName("safeBoolean")
+fun Metoid.boolean(default: Boolean, key: String? = null) = SafeBooleanDelegate(key, default)
+
+@JvmName("safeNumber")
+fun Metoid.number(default: Number, key: String? = null) = SafeNumberDelegate(key, default)
+
+inline fun <reified E : Enum<E>> Metoid.enum(default: E, key: String? = null) = SafeEnumDelegate(key, default) { enumValueOf(it) }
+
+/* Configuration delegates */
+
+class ValueConfigDelegate(private val key: String? = null, private val default: Value? = null) : ReadWriteProperty<Configurable, Value?> {
+    override fun getValue(thisRef: Configurable, property: KProperty<*>): Value? {
+        return thisRef.config[key ?: property.name]?.value ?: default
+    }
+
+    override fun setValue(thisRef: Configurable, property: KProperty<*>, value: Value?) {
+        thisRef.config[key ?: property.name] = value
+    }
+}
+
+class StringConfigDelegate(private val key: String? = null, private val default: String? = null) : ReadWriteProperty<Configurable, String?> {
+    override fun getValue(thisRef: Configurable, property: KProperty<*>): String? {
+        return thisRef.config[key ?: property.name]?.string ?: default
+    }
+
+    override fun setValue(thisRef: Configurable, property: KProperty<*>, value: String?) {
+        thisRef.config[key ?: property.name] = value
+    }
+}
+
+class BooleanConfigDelegate(private val key: String? = null, private val default: Boolean? = null) : ReadWriteProperty<Configurable, Boolean?> {
+    override fun getValue(thisRef: Configurable, property: KProperty<*>): Boolean? {
+        return thisRef.config[key ?: property.name]?.boolean ?: default
+    }
+
+    override fun setValue(thisRef: Configurable, property: KProperty<*>, value: Boolean?) {
+        thisRef.config[key ?: property.name] = value
+    }
+}
+
+class NumberConfigDelegate(private val key: String? = null, private val default: Number? = null) : ReadWriteProperty<Configurable, Number?> {
+    override fun getValue(thisRef: Configurable, property: KProperty<*>): Number? {
+        return thisRef.config[key ?: property.name]?.number ?: default
+    }
+
+    override fun setValue(thisRef: Configurable, property: KProperty<*>, value: Number?) {
+        thisRef.config[key ?: property.name] = value
+    }
+}
+
+//Delegates with non-null values
+
+class SafeStringConfigDelegate(private val key: String? = null, private val default: String) : ReadWriteProperty<Configurable, String> {
+    override fun getValue(thisRef: Configurable, property: KProperty<*>): String {
+        return thisRef.config[key ?: property.name]?.string ?: default
+    }
+
+    override fun setValue(thisRef: Configurable, property: KProperty<*>, value: String) {
+        thisRef.config[key ?: property.name] = value
+    }
+}
+
+class SafeBooleanConfigDelegate(private val key: String? = null, private val default: Boolean) : ReadWriteProperty<Configurable, Boolean> {
+    override fun getValue(thisRef: Configurable, property: KProperty<*>): Boolean {
+        return thisRef.config[key ?: property.name]?.boolean ?: default
+    }
+
+    override fun setValue(thisRef: Configurable, property: KProperty<*>, value: Boolean) {
+        thisRef.config[key ?: property.name] = value
+    }
+}
+
+class SafeNumberConfigDelegate(private val key: String? = null, private val default: Number) : ReadWriteProperty<Configurable, Number> {
+    override fun getValue(thisRef: Configurable, property: KProperty<*>): Number {
+        return thisRef.config[key ?: property.name]?.number ?: default
+    }
+
+    override fun setValue(thisRef: Configurable, property: KProperty<*>, value: Number) {
+        thisRef.config[key ?: property.name] = value
+    }
+}
+
+class SafeEnumvConfigDelegate<E : Enum<E>>(private val key: String? = null, private val default: E, private val resolver: (String) -> E) : ReadWriteProperty<Configurable, E> {
+    override fun getValue(thisRef: Configurable, property: KProperty<*>): E {
+        return (thisRef.config[key ?: property.name]?.string)?.let { resolver(it) } ?: default
+    }
+
+    override fun setValue(thisRef: Configurable, property: KProperty<*>, value: E) {
+        thisRef.config[key ?: property.name] = value.name
+    }
+}
+
+//Child node delegate
+
+class ChildConfigDelegate<T : Configurable>(private val key: String? = null, private val converter: (Configuration) -> T) : ReadWriteProperty<Configurable, T> {
+    override fun getValue(thisRef: Configurable, property: KProperty<*>): T {
+        return converter(thisRef.config.get(key ?: property.name)?.node ?: Configuration())
+    }
+
+    override fun setValue(thisRef: Configurable, property: KProperty<*>, value: T) {
+        thisRef.config[key ?: property.name] = value.config
+    }
+
+}
+
+//Read-write delegates
+
+/**
+ * A property delegate that uses custom key
+ */
+fun Configurable.value(default: Value = Null, key: String? = null) = ValueConfigDelegate(key, default)
+
+fun Configurable.string(default: String? = null, key: String? = null) = StringConfigDelegate(key, default)
+
+fun Configurable.boolean(default: Boolean? = null, key: String? = null) = BooleanConfigDelegate(key, default)
+
+fun Configurable.number(default: Number? = null, key: String? = null) = NumberConfigDelegate(key, default)
+
+fun Configurable.child(key: String? = null) = ChildConfigDelegate(key) { SimpleConfigurable(it) }
+
+fun <T : Configurable> Configurable.child(key: String? = null, converter: (Configuration) -> T) = ChildConfigDelegate(key, converter)
+
+//fun <T : Configurable> Configurable.spec(spec: Specification<T>, key: String? = null) = ChildConfigDelegate<T>(key) { spec.wrap(this) }
+
+@JvmName("safeString")
+fun Configurable.string(default: String, key: String? = null) = SafeStringConfigDelegate(key, default)
+
+@JvmName("safeBoolean")
+fun Configurable.boolean(default: Boolean, key: String? = null) = SafeBooleanConfigDelegate(key, default)
+
+@JvmName("safeNumber")
+fun Configurable.number(default: Number, key: String? = null) = SafeNumberConfigDelegate(key, default)
+
+inline fun <reified E : Enum<E>> Configurable.enum(default: E, key: String? = null) = SafeEnumvConfigDelegate(key, default) { enumValueOf(it) }

src/main/kotlin/hep/dataforge/meta/Meta.kt

@@ -85,4 +85,11 @@ class SealedMeta(meta: Meta) : MetaNode<SealedMeta>() {
 /**
  * Generate sealed node from [this]. If it is already sealed return it as is
  */
-fun Meta.seal(): SealedMeta = this as? SealedMeta ?: SealedMeta(this)
+fun Meta.seal(): SealedMeta = this as? SealedMeta ?: SealedMeta(this)
+
+/**
+ * Generic meta-holder object
+ */
+interface Metoid{
+    val meta: Meta
+}

src/main/kotlin/hep/dataforge/meta/MetaBuilder.kt

@@ -1,7 +1,7 @@
 package hep.dataforge.meta
 
 /**
- * DSL builder for meta
+ * DSL builder for meta. Is not intended to store mutable state
  */
 class MetaBuilder : MutableMetaNode<MetaBuilder>() {
     override fun wrap(meta: Meta): MetaBuilder = meta.builder()

src/main/kotlin/hep/dataforge/meta/MutableMetaNode.kt

@@ -9,8 +9,8 @@ class MetaListener(val owner: Any? = null, val action: (name: Name, oldItem: Met
 }
 
 
-interface MutableMeta<M : MutableMeta<M>>: Meta{
+interface MutableMeta<M : MutableMeta<M>> : Meta {
-    operator fun set(name: Name, item: MetaItem<M>)
+    operator fun set(name: Name, item: MetaItem<M>?)
 }
 
 /**
@@ -69,7 +69,7 @@ abstract class MutableMetaNode<M : MutableMetaNode<M>> : MetaNode<M>(), MutableM
      */
     protected abstract fun empty(): M
 
-    override operator fun set(name: Name, item: MetaItem<M>) {
+    override operator fun set(name: Name, item: MetaItem<M>?) {
         when (name.length) {
             0 -> error("Can't set meta item for empty name")
             1 -> {
@@ -87,6 +87,8 @@ abstract class MutableMetaNode<M : MutableMetaNode<M>> : MetaNode<M>(), MutableM
         }
     }
 
+    fun remove(name: String) = set(name.toName(), null)
+
     operator fun set(name: Name, value: Value) = set(name, MetaItem.ValueItem(value))
     operator fun set(name: Name, meta: Meta) = set(name, MetaItem.SingleNodeItem(wrap(meta)))
     operator fun set(name: Name, metas: List<Meta>) = set(name, MetaItem.MultiNodeItem(metas.map { wrap(it) }))

src/test/kotlin/hep/dataforge/meta/MetaDelegateTest.kt

@@ -0,0 +1,27 @@
+package hep.dataforge.meta
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+
+class MetaDelegateTest {
+    enum class TestEnum {
+        YES,
+        NO
+    }
+
+    @Test
+    fun delegateTest() {
+        val testObject = object : SimpleConfigurable(Configuration()) {
+            var myValue by string()
+            var safeValue by number(2.2)
+            var enumValue by enum(TestEnum.YES)
+        }
+        testObject.config["myValue"] = "theString"
+        testObject.enumValue = TestEnum.NO
+        assertEquals("theString", testObject.myValue)
+        assertEquals(TestEnum.NO, testObject.enumValue)
+        assertEquals(2.2, testObject.safeValue)
+    }
+
+}