diff --git a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/descriptors/NodeDescriptor.kt b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/descriptors/NodeDescriptor.kt
index bbc9fdcc..902c81a3 100644
--- a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/descriptors/NodeDescriptor.kt
+++ b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/descriptors/NodeDescriptor.kt
@@ -75,7 +75,7 @@ class NodeDescriptor(override val config: Config) : Specific {
      *
      * @return
      */
-    var tags: List<String> by value().map { value ->
+    var tags: List<String> by value{ value ->
         value?.list?.map { it.string } ?: emptyList()
     }
 
diff --git a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/ConfigDelegates.kt b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/ConfigDelegates.kt
index 9a5a72c5..9baa802a 100644
--- a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/ConfigDelegates.kt
+++ b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/ConfigDelegates.kt
@@ -1,6 +1,5 @@
 package hep.dataforge.meta
 
-import hep.dataforge.values.Null
 import hep.dataforge.values.Value
 import kotlin.jvm.JvmName
 
@@ -10,9 +9,18 @@ import kotlin.jvm.JvmName
 /**
  * A property delegate that uses custom key
  */
-fun Configurable.value(default: Any = Null, key: String? = null) =
+fun <T> Configurable.value(default: T, key: String? = null) =
     MutableValueDelegate(config, key, Value.of(default))
 
+fun <T> Configurable.value(default: T? = null, key: String? = null, transform: (Value?) -> T) =
+    MutableValueDelegate(config, key, Value.of(default)).transform(reader = transform)
+
+fun Configurable.stringList(key: String? = null) =
+    value { it?.list?.map { value -> value.string } ?: emptyList() }
+
+fun Configurable.numberList(key: String? = null) =
+    value { it?.list?.map { value -> value.number } ?: emptyList() }
+
 fun Configurable.string(default: String? = null, key: String? = null) =
     MutableStringDelegate(config, key, default)
 
@@ -93,10 +101,12 @@ fun Configurable.float(default: Float, key: String? = null) =
 inline fun <reified E : Enum<E>> Configurable.enum(default: E, key: String? = null) =
     MutableSafeEnumvDelegate(config, key, default) { enumValueOf(it) }
 
+/* Node delegates */
+
 fun Configurable.node(key: String? = null) = MutableNodeDelegate(config, key)
 
 fun <T : Specific> Configurable.spec(spec: Specification<T>, key: String? = null) =
     MutableMorphDelegate(config, key) { spec.wrap(it) }
 
 fun <T : Specific> Configurable.spec(builder: (Config) -> T, key: String? = null) =
-    MutableMorphDelegate(config, key) { specification(builder).wrap(it) }
\ No newline at end of file
+    MutableMorphDelegate(config, key) { specification(builder).wrap(it) }
diff --git a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Delegates.kt b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Delegates.kt
index ba3bd883..377ec994 100644
--- a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Delegates.kt
+++ b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Delegates.kt
@@ -184,7 +184,7 @@ class MutableValueDelegate<M : MutableMeta<M>>(
         }
     }
 
-    fun <T> map(writer: (T) -> Value? = { Value.of(it) }, reader: (Value?) -> T) =
+    fun <T> transform(writer: (T) -> Value? = { Value.of(it) }, reader: (Value?) -> T) =
         ReadWriteDelegateWrapper(this, reader, writer)
 }