Merge pull request #1097 from Kotlin/map_unfold

Map unfold

Author: AndreiKingsley

core/api/core.api

@@ -1783,7 +1783,6 @@ public final class org/jetbrains/kotlinx/dataframe/api/DataColumnTypeKt {
 	public static final fun isFrameColumn (Lorg/jetbrains/kotlinx/dataframe/DataColumn;)Z
 	public static final fun isList (Lorg/jetbrains/kotlinx/dataframe/DataColumn;)Z
 	public static final fun isNumber (Lorg/jetbrains/kotlinx/dataframe/DataColumn;)Z
-	public static final fun isPrimitive (Lorg/jetbrains/kotlinx/dataframe/DataColumn;)Z
 	public static final fun isSubtypeOf (Lorg/jetbrains/kotlinx/dataframe/DataColumn;Lkotlin/reflect/KType;)Z
 	public static final fun isValueColumn (Lorg/jetbrains/kotlinx/dataframe/DataColumn;)Z
 	public static final fun valuesAreComparable (Lorg/jetbrains/kotlinx/dataframe/DataColumn;)Z
@@ -5254,6 +5253,7 @@ public final class org/jetbrains/kotlinx/dataframe/impl/api/SchemaKt {
 public final class org/jetbrains/kotlinx/dataframe/impl/api/ToDataFrameKt {
 	public static final fun convertToDataFrame (Ljava/lang/Iterable;Lkotlin/reflect/KClass;Ljava/util/List;Ljava/util/Set;Ljava/util/Set;Ljava/util/Set;I)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
 	public static final fun createDataFrameImpl (Ljava/lang/Iterable;Lkotlin/reflect/KClass;Lkotlin/jvm/functions/Function1;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
+	public static final fun getCanBeUnfolded (Lkotlin/reflect/KClass;)Z
 	public static final fun getHasProperties (Lkotlin/reflect/KClass;)Z
 	public static final fun isValueType (Lkotlin/reflect/KClass;)Z
 }

core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/DataColumnType.kt

@@ -16,12 +16,10 @@ import java.math.BigDecimal
 import java.math.BigInteger
 import kotlin.contracts.ExperimentalContracts
 import kotlin.contracts.contract
-import kotlin.reflect.KClass
 import kotlin.reflect.KType
 import kotlin.reflect.KTypeProjection
 import kotlin.reflect.KVariance
 import kotlin.reflect.full.createType
-import kotlin.reflect.full.isSubclassOf
 import kotlin.reflect.full.isSubtypeOf
 import kotlin.reflect.full.withNullability
 import kotlin.reflect.typeOf
@@ -81,13 +79,3 @@ public fun AnyCol.valuesAreComparable(): Boolean =
                 nullable = hasNulls(),
             ),
         )
-
-@PublishedApi
-internal fun AnyCol.isPrimitive(): Boolean = typeClass.isPrimitive()
-
-internal fun KClass<*>.isPrimitive(): Boolean =
-    isSubclassOf(Number::class) ||
-        this == String::class ||
-        this == Char::class ||
-        this == Array::class ||
-        isSubclassOf(Collection::class)

core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/toDataFrame.kt

@@ -11,9 +11,8 @@ import org.jetbrains.kotlinx.dataframe.annotations.Interpretable
 import org.jetbrains.kotlinx.dataframe.annotations.Refine
 import org.jetbrains.kotlinx.dataframe.columns.ColumnPath
 import org.jetbrains.kotlinx.dataframe.impl.ColumnNameGenerator
+import org.jetbrains.kotlinx.dataframe.impl.api.canBeUnfolded
 import org.jetbrains.kotlinx.dataframe.impl.api.createDataFrameImpl
-import org.jetbrains.kotlinx.dataframe.impl.api.hasProperties
-import org.jetbrains.kotlinx.dataframe.impl.api.isValueType
 import org.jetbrains.kotlinx.dataframe.impl.asList
 import org.jetbrains.kotlinx.dataframe.impl.columnName
 import org.jetbrains.kotlinx.dataframe.impl.columns.createColumnGuessingType
@@ -30,7 +29,7 @@ public inline fun <reified T> Iterable<T>.toDataFrame(): DataFrame<T> =
     toDataFrame {
         // check if type is value: primitives, primitive arrays, datetime types etc.,
         // or has no properties
-        if (T::class.isValueType || !T::class.hasProperties) {
+        if (!T::class.canBeUnfolded) {
             // create a single `value` column
             ValueProperty<T>::value from { it }
         } else {

core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/unfold.kt

@@ -8,6 +8,7 @@ import org.jetbrains.kotlinx.dataframe.DataFrame
 import org.jetbrains.kotlinx.dataframe.annotations.AccessApiOverload
 import org.jetbrains.kotlinx.dataframe.columns.ColumnKind
 import org.jetbrains.kotlinx.dataframe.columns.toColumnSet
+import org.jetbrains.kotlinx.dataframe.impl.api.canBeUnfolded
 import org.jetbrains.kotlinx.dataframe.impl.api.createDataFrameImpl
 import org.jetbrains.kotlinx.dataframe.typeClass
 import kotlin.reflect.KProperty
@@ -17,7 +18,7 @@ public inline fun <reified T> DataColumn<T>.unfold(): AnyCol =
         ColumnKind.Group, ColumnKind.Frame -> this
 
         else -> when {
-            isPrimitive() -> this
+            !typeClass.canBeUnfolded -> this
 
             else -> values()
                 .createDataFrameImpl(typeClass) { (this as CreateDataFrameDsl<T>).properties() }

core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/api/toDataFrame.kt

@@ -56,8 +56,24 @@ private val valueTypes = setOf(
     kotlinx.datetime.TimeZone::class,
     kotlinx.datetime.DateTimePeriod::class,
     kotlinx.datetime.DateTimeUnit::class,
+    Map::class,
+    MutableMap::class,
 )
 
+/**
+ * Determines whether a class can be unfolded into its properties.
+ *
+ * A class is considered **unfoldable** if it has at least one public property
+ * or getter-like function. This excludes:
+ * - **Value types** such as primitives, enums, and date-time types.
+ * - **Classes without properties**, including empty or marker classes.
+ *
+ * @return `true` if the class has unfoldable properties, `false` otherwise.
+ */
+@PublishedApi
+internal val KClass<*>.canBeUnfolded: Boolean
+    get() = (!this.isValueType) && this.hasProperties
+
 /**
  * Checks if `KClass` is a value type (number, datetime, string, etc.)
  * Should be aligned with `ConeKotlinType.isValueType()` in

core/src/test/kotlin/org/jetbrains/kotlinx/dataframe/api/toDataFrame.kt

@@ -398,6 +398,14 @@ class CreateDataFrameTests {
         enums.toDataFrame() shouldBe dataFrameOf("value")(*enums.toTypedArray())
     }
 
+    @Test
+    fun `should convert iterables of non-JSON Map to DataFrame with value column`() {
+        val maps: List<Map<*, *>?> = listOf(mapOf(1 to null, 2 to "val"), mapOf(3 to 1, 4 to true), null)
+        val df = maps.toDataFrame()
+        df.columnNames() shouldBe listOf("value")
+        df["value"].toList() shouldBe maps
+    }
+
     class NoPublicPropsClass(private val a: Int, private val b: String)
 
     @Test

plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/api/toDataFrame.kt

@@ -198,10 +198,14 @@ internal fun KotlinTypeFacade.toDataFrame(
     traverseConfiguration: TraverseConfiguration,
 ): PluginDataFrameSchema {
 
+    val anyType = session.builtinTypes.nullableAnyType.type
+
     fun ConeKotlinType.isValueType() =
         this.isArrayTypeOrNullableArrayType ||
             this.classId == StandardClassIds.Unit ||
             this.classId == StandardClassIds.Any ||
+            this.classId == StandardClassIds.Map ||
+            this.classId == StandardClassIds.MutableMap ||
             this.classId == StandardClassIds.String ||
             this.classId in StandardClassIds.primitiveTypes ||
             this.classId in StandardClassIds.unsignedTypes ||
@@ -226,6 +230,7 @@ internal fun KotlinTypeFacade.toDataFrame(
                 Names.TEMPORAL_AMOUNT_CLASS_ID.constructClassLikeType(emptyArray(), isNullable = true), session
             )
 
+
     fun FirNamedFunctionSymbol.isGetterLike(): Boolean {
         val functionName = this.name.asString()
         return (functionName.startsWith("get") || functionName.startsWith("is")) &&

plugins/kotlin-dataframe/testData/box/toDataFrameValueTypes.kt

@@ -197,6 +197,12 @@ fun box(): String {
     val enumColNullable: DataColumn<EnumExample?> = enumDfNullable.value
     enumColNullable.print()
 
+    // Non-JSON Map
+
+    val mapsDfNullable = listOf(mapOf(1 to null, 2 to "val"), mapOf(3 to 1, 4 to true), null).toDataFrame()
+    val mapsColNullable: DataColumn<Map<*, *>?> = mapsDfNullable.value
+    mapsColNullable.print()
+
     return "OK"
 }