diff --git a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/descriptors/MetaDescriptorBuilder.kt b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/descriptors/MetaDescriptorBuilder.kt
index 7688f3cc..d123bb54 100644
--- a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/descriptors/MetaDescriptorBuilder.kt
+++ b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/descriptors/MetaDescriptorBuilder.kt
@@ -90,9 +90,8 @@ public class MetaDescriptorBuilder internal constructor() {
     )
 }
 
-public fun MetaDescriptorBuilder.item(name: String, block: MetaDescriptorBuilder.() -> Unit) {
+public fun MetaDescriptorBuilder.item(name: String, block: MetaDescriptorBuilder.() -> Unit): MetaDescriptorBuilder =
     item(Name.parse(name), block)
-}
 
 public fun MetaDescriptor(block: MetaDescriptorBuilder.() -> Unit): MetaDescriptor =
     MetaDescriptorBuilder().apply(block).build()
diff --git a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/descriptors/schemeDescriptor.kt b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/descriptors/schemeDescriptor.kt
index 060d3a80..03104104 100644
--- a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/descriptors/schemeDescriptor.kt
+++ b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/descriptors/schemeDescriptor.kt
@@ -9,34 +9,32 @@ import kotlin.reflect.typeOf
 public inline fun <S : Scheme, reified T> MetaDescriptorBuilder.value(
     property: KProperty1<S, T>,
     noinline block: MetaDescriptorBuilder.() -> Unit = {},
-) {
-    when (typeOf<T>()) {
-        typeOf<Number>(), typeOf<Int>(), typeOf<Double>(), typeOf<Short>(), typeOf<Long>(), typeOf<Float>() ->
-            value(property.name, ValueType.NUMBER) {
-                block()
-            }
-        typeOf<Number?>(), typeOf<Int?>(), typeOf<Double?>(), typeOf<Short?>(), typeOf<Long?>(), typeOf<Float?>() ->
-            value(property.name, ValueType.NUMBER) {
-                block()
-            }
-        typeOf<Boolean>() -> value(property.name, ValueType.BOOLEAN) {
+): MetaDescriptorBuilder = when (typeOf<T>()) {
+    typeOf<Number>(), typeOf<Int>(), typeOf<Double>(), typeOf<Short>(), typeOf<Long>(), typeOf<Float>() ->
+        value(property.name, ValueType.NUMBER) {
             block()
         }
-        typeOf<List<Number>>(), typeOf<List<Int>>(), typeOf<List<Double>>(), typeOf<List<Short>>(), typeOf<List<Long>>(), typeOf<List<Float>>(),
-        typeOf<IntArray>(), typeOf<DoubleArray>(), typeOf<ShortArray>(), typeOf<LongArray>(), typeOf<FloatArray>(),
-        -> value(property.name, ValueType.NUMBER) {
-            multiple = true
+    typeOf<Number?>(), typeOf<Int?>(), typeOf<Double?>(), typeOf<Short?>(), typeOf<Long?>(), typeOf<Float?>() ->
+        value(property.name, ValueType.NUMBER) {
             block()
         }
-        typeOf<String>() -> value(property.name, ValueType.STRING) {
-            block()
-        }
-        typeOf<List<String>>(), typeOf<Array<String>>() -> value(property.name, ValueType.STRING) {
-            multiple = true
-            block()
-        }
-        else -> item(property.name, block)
+    typeOf<Boolean>() -> value(property.name, ValueType.BOOLEAN) {
+        block()
     }
+    typeOf<List<Number>>(), typeOf<List<Int>>(), typeOf<List<Double>>(), typeOf<List<Short>>(), typeOf<List<Long>>(), typeOf<List<Float>>(),
+    typeOf<IntArray>(), typeOf<DoubleArray>(), typeOf<ShortArray>(), typeOf<LongArray>(), typeOf<FloatArray>(),
+    -> value(property.name, ValueType.NUMBER) {
+        multiple = true
+        block()
+    }
+    typeOf<String>() -> value(property.name, ValueType.STRING) {
+        block()
+    }
+    typeOf<List<String>>(), typeOf<Array<String>>() -> value(property.name, ValueType.STRING) {
+        multiple = true
+        block()
+    }
+    else -> item(property.name, block)
 }
 
 public inline fun <S : Scheme, reified T : Scheme> MetaDescriptorBuilder.scheme(