diff --git a/core/api/core.api b/core/api/core.api
index f764cd4945..fe2d668a07 100644
--- a/core/api/core.api
+++ b/core/api/core.api
@@ -2359,11 +2359,13 @@ public final class org/jetbrains/kotlinx/dataframe/api/Gather {
 	public fun <init> (Lorg/jetbrains/kotlinx/dataframe/DataFrame;Lkotlin/jvm/functions/Function2;Lkotlin/jvm/functions/Function2;Lkotlin/reflect/KType;Lkotlin/jvm/functions/Function1;Lkotlin/jvm/functions/Function1;Z)V
 	public synthetic fun <init> (Lorg/jetbrains/kotlinx/dataframe/DataFrame;Lkotlin/jvm/functions/Function2;Lkotlin/jvm/functions/Function2;Lkotlin/reflect/KType;Lkotlin/jvm/functions/Function1;Lkotlin/jvm/functions/Function1;ZILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun cast ()Lorg/jetbrains/kotlinx/dataframe/api/Gather;
-	public final fun copy (Lorg/jetbrains/kotlinx/dataframe/DataFrame;Lkotlin/jvm/functions/Function2;Lkotlin/jvm/functions/Function2;Lkotlin/reflect/KType;Lkotlin/jvm/functions/Function1;Lkotlin/jvm/functions/Function1;Z)Lorg/jetbrains/kotlinx/dataframe/api/Gather;
-	public static synthetic fun copy$default (Lorg/jetbrains/kotlinx/dataframe/api/Gather;Lorg/jetbrains/kotlinx/dataframe/DataFrame;Lkotlin/jvm/functions/Function2;Lkotlin/jvm/functions/Function2;Lkotlin/reflect/KType;Lkotlin/jvm/functions/Function1;Lkotlin/jvm/functions/Function1;ZILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/api/Gather;
-	public fun equals (Ljava/lang/Object;)Z
-	public fun hashCode ()I
-	public fun toString ()Ljava/lang/String;
+	public final fun getColumns ()Lkotlin/jvm/functions/Function2;
+	public final fun getDf ()Lorg/jetbrains/kotlinx/dataframe/DataFrame;
+	public final fun getExplode ()Z
+	public final fun getFilter ()Lkotlin/jvm/functions/Function2;
+	public final fun getKeyTransform ()Lkotlin/jvm/functions/Function1;
+	public final fun getKeyType ()Lkotlin/reflect/KType;
+	public final fun getValueTransform ()Lkotlin/jvm/functions/Function1;
 }
 
 public final class org/jetbrains/kotlinx/dataframe/api/GatherKt {
@@ -5463,7 +5465,7 @@ public final class org/jetbrains/kotlinx/dataframe/exceptions/CellConversionExce
 	public final fun getRow ()Ljava/lang/Integer;
 }
 
-public final class org/jetbrains/kotlinx/dataframe/exceptions/ColumnNotFoundException : java/lang/RuntimeException, org/jetbrains/kotlinx/dataframe/exceptions/DataFrameException {
+public final class org/jetbrains/kotlinx/dataframe/exceptions/ColumnNotFoundException : java/lang/RuntimeException, org/jetbrains/kotlinx/dataframe/exceptions/DataFrameError {
 	public fun <init> (Ljava/lang/String;Ljava/lang/String;)V
 	public final fun getColumnName ()Ljava/lang/String;
 	public fun getMessage ()Ljava/lang/String;
@@ -5474,11 +5476,11 @@ public final class org/jetbrains/kotlinx/dataframe/exceptions/ColumnTypeMismatch
 	public final fun getColumn ()Lorg/jetbrains/kotlinx/dataframe/DataColumn;
 }
 
-public abstract interface class org/jetbrains/kotlinx/dataframe/exceptions/DataFrameException {
+public abstract interface class org/jetbrains/kotlinx/dataframe/exceptions/DataFrameError {
 	public abstract fun getMessage ()Ljava/lang/String;
 }
 
-public final class org/jetbrains/kotlinx/dataframe/exceptions/DuplicateColumnNamesException : java/lang/IllegalArgumentException, org/jetbrains/kotlinx/dataframe/exceptions/DataFrameException {
+public final class org/jetbrains/kotlinx/dataframe/exceptions/DuplicateColumnNamesException : java/lang/IllegalArgumentException, org/jetbrains/kotlinx/dataframe/exceptions/DataFrameError {
 	public fun <init> (Ljava/util/List;)V
 	public final fun getAllColumnNames ()Ljava/util/List;
 	public final fun getDuplicatedNames ()Ljava/util/List;
@@ -5755,6 +5757,10 @@ public final class org/jetbrains/kotlinx/dataframe/impl/aggregation/receivers/Ag
 	public static final fun internal (Lorg/jetbrains/kotlinx/dataframe/aggregation/AggregateDsl;)Lorg/jetbrains/kotlinx/dataframe/impl/aggregation/receivers/AggregateInternalDsl;
 }
 
+public final class org/jetbrains/kotlinx/dataframe/impl/api/ConstructorsKt {
+	public static final fun withValuesImpl (Lkotlin/Pair;)Ljava/util/List;
+}
+
 public final class org/jetbrains/kotlinx/dataframe/impl/api/ConvertKt {
 	public static final fun convertRowColumnImpl (Lorg/jetbrains/kotlinx/dataframe/api/Convert;Lkotlin/reflect/KType;Lorg/jetbrains/kotlinx/dataframe/api/Infer;Lkotlin/jvm/functions/Function2;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
 	public static final fun withRowCellImpl (Lorg/jetbrains/kotlinx/dataframe/api/Convert;Lkotlin/reflect/KType;Lorg/jetbrains/kotlinx/dataframe/api/Infer;Lkotlin/jvm/functions/Function2;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/constructors.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/constructors.kt
index 37bf0994ad..cfecd4fcf9 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/constructors.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/constructors.kt
@@ -393,7 +393,7 @@ public class DataFrameBuilder(private val header: List<String>) {
 
     @JvmName("invoke1")
     internal fun withValues(values: Iterable<Any?>): DataFrame<*> =
-        withValuesImpl(header, values.asList()).map { (name, values) ->
+        (header to values.asList()).withValuesImpl().map { (name, values) ->
             DataColumn.createByInference(name, values)
         }.toDataFrame()
 
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/gather.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/gather.kt
index 76042d293f..bfe9b3c090 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/gather.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/gather.kt
@@ -4,6 +4,8 @@ import org.jetbrains.kotlinx.dataframe.ColumnsSelector
 import org.jetbrains.kotlinx.dataframe.DataFrame
 import org.jetbrains.kotlinx.dataframe.RowValueFilter
 import org.jetbrains.kotlinx.dataframe.annotations.AccessApiOverload
+import org.jetbrains.kotlinx.dataframe.annotations.Interpretable
+import org.jetbrains.kotlinx.dataframe.annotations.Refine
 import org.jetbrains.kotlinx.dataframe.columns.ColumnAccessor
 import org.jetbrains.kotlinx.dataframe.columns.ColumnReference
 import org.jetbrains.kotlinx.dataframe.columns.toColumnSet
@@ -15,6 +17,7 @@ import kotlin.reflect.typeOf
 
 // region gather
 
+@Interpretable("Gather0")
 public fun <T, C> DataFrame<T>.gather(selector: ColumnsSelector<T, C>): Gather<T, C, String, C> =
     Gather(
         df = this,
@@ -44,30 +47,76 @@ public fun <T, C> DataFrame<T>.gather(vararg columns: KProperty<C>): Gather<T, C
 
 // endregion
 
+@Interpretable("GatherWhere")
 public fun <T, C, K, R> Gather<T, C, K, R>.where(filter: RowValueFilter<T, C>): Gather<T, C, K, R> =
-    copy(filter = this.filter and filter)
+    Gather(
+        df = df,
+        columns = columns,
+        filter = this.filter and filter,
+        keyType = keyType,
+        keyTransform = keyTransform,
+        valueTransform = valueTransform,
+        explode = explode,
+    )
 
+@Interpretable("GatherChangeType")
 public fun <T, C, K, R> Gather<T, C?, K, R>.notNull(): Gather<T, C, K, R> = where { it != null } as Gather<T, C, K, R>
 
-public fun <T, C, K, R> Gather<T, C, K, R>.explodeLists(): Gather<T, C, K, R> = copy(explode = true)
+@Interpretable("GatherExplodeLists")
+public fun <T, C, K, R> Gather<T, C, K, R>.explodeLists(): Gather<T, C, K, R> =
+    Gather(
+        df = df,
+        columns = columns,
+        filter = filter,
+        keyType = keyType,
+        keyTransform = keyTransform,
+        valueTransform = valueTransform,
+        explode = true,
+    )
 
+@Interpretable("GatherMap")
 public inline fun <T, C, reified K, R> Gather<T, C, *, R>.mapKeys(
     noinline transform: (String) -> K,
 ): Gather<T, C, K, R> =
-    copy(keyTransform = transform as ((String) -> Nothing), keyType = typeOf<K>()) as Gather<T, C, K, R>
+    Gather(
+        df = df,
+        columns = columns,
+        filter = filter,
+        keyType = typeOf<K>(),
+        keyTransform = transform,
+        valueTransform = valueTransform,
+        explode = explode,
+    )
 
+@Interpretable("GatherMap")
 public fun <T, C, K, R> Gather<T, C, K, *>.mapValues(transform: (C) -> R): Gather<T, C, K, R> =
-    copy(valueTransform = transform as ((C) -> Nothing)) as Gather<T, C, K, R>
+    Gather(
+        df = df,
+        columns = columns,
+        filter = filter,
+        keyType = keyType,
+        keyTransform = keyTransform,
+        valueTransform = transform,
+        explode = explode,
+    )
 
-public data class Gather<T, C, K, R>(
+public class Gather<T, C, K, R>(
+    @PublishedApi
     internal val df: DataFrame<T>,
+    @PublishedApi
     internal val columns: ColumnsSelector<T, C>,
+    @PublishedApi
     internal val filter: RowValueFilter<T, C>? = null,
+    @PublishedApi
     internal val keyType: KType? = null,
+    @PublishedApi
     internal val keyTransform: ((String) -> K),
+    @PublishedApi
     internal val valueTransform: ((C) -> R)? = null,
+    @PublishedApi
     internal val explode: Boolean = false,
 ) {
+    @Interpretable("GatherChangeType")
     public fun <P> cast(): Gather<T, P, K, P> {
         // TODO: introduce GatherWithTransform to avoid this error
         require(valueTransform == null) { "Cast is not allowed to be called after `mapValues`" }
@@ -77,6 +126,8 @@ public data class Gather<T, C, K, R>(
 
 // region into
 
+@Refine
+@Interpretable("GatherInto")
 public fun <T, C, K, R> Gather<T, C, K, R>.into(keyColumn: String, valueColumn: String): DataFrame<T> =
     gatherImpl(keyColumn, valueColumn)
 
@@ -100,6 +151,8 @@ public fun <T, C, K, R> Gather<T, C, K, R>.into(keyColumn: KProperty<K>, valueCo
 
 // region keysInto
 
+@Refine
+@Interpretable("GatherKeysInto")
 public fun <T, C, K, R> Gather<T, C, K, R>.keysInto(keyColumn: String): DataFrame<T> = gatherImpl(keyColumn, null)
 
 @Deprecated(
@@ -120,6 +173,8 @@ public fun <T, C, K, R> Gather<T, C, K, R>.keysInto(keyColumn: KProperty<K>): Da
 
 // region valuesInto
 
+@Refine
+@Interpretable("GatherValuesInto")
 public fun <T, C, K, R> Gather<T, C, K, R>.valuesInto(valueColumn: String): DataFrame<T> = gatherImpl(null, valueColumn)
 
 @Deprecated(
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/exceptions/ColumnNotFoundException.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/exceptions/ColumnNotFoundException.kt
index 7d037acffa..91b61f4117 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/exceptions/ColumnNotFoundException.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/exceptions/ColumnNotFoundException.kt
@@ -2,4 +2,4 @@ package org.jetbrains.kotlinx.dataframe.exceptions
 
 public class ColumnNotFoundException(public val columnName: String, public override val message: String) :
     RuntimeException(),
-    DataFrameException
+    DataFrameError
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/exceptions/DataFrameException.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/exceptions/DataFrameError.kt
similarity index 53%
rename from core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/exceptions/DataFrameException.kt
rename to core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/exceptions/DataFrameError.kt
index 4d3529e5d9..b0dfc17f77 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/exceptions/DataFrameException.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/exceptions/DataFrameError.kt
@@ -1,8 +1,9 @@
 package org.jetbrains.kotlinx.dataframe.exceptions
 
 /**
- * If DataFrame function used by compiler plugin as implementation detail throws this exception, [message] will be reported as warning
+ * If DataFrame function used by compiler plugin as implementation detail throws exception
+ * that implements this interface, [message] will be reported as warning
  */
-public interface DataFrameException {
+public interface DataFrameError {
     public val message: String
 }
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/exceptions/DuplicateColumnNamesException.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/exceptions/DuplicateColumnNamesException.kt
index 890d9547cb..2e219a02e4 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/exceptions/DuplicateColumnNamesException.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/exceptions/DuplicateColumnNamesException.kt
@@ -2,7 +2,7 @@ package org.jetbrains.kotlinx.dataframe.exceptions
 
 public class DuplicateColumnNamesException(public val allColumnNames: List<String>) :
     IllegalArgumentException(),
-    DataFrameException {
+    DataFrameError {
 
     public val duplicatedNames: List<String> = allColumnNames
         .groupBy { it }
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/api/constructors.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/api/constructors.kt
index ba166e3e2e..30495180e1 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/api/constructors.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/api/constructors.kt
@@ -1,10 +1,16 @@
 package org.jetbrains.kotlinx.dataframe.impl.api
 
-internal fun <T> withValuesImpl(header: List<String>, values: List<T>): List<Pair<String, List<T>>> {
+import org.jetbrains.kotlinx.dataframe.exceptions.DataFrameError
+
+/**
+ * Public API to be re-used in compiler plugin implementation
+ */
+public fun <T> Pair<List<String>, List<T>>.withValuesImpl(): List<Pair<String, List<T>>> {
+    val (header, values) = this
     val ncol = header.size
 
-    require(header.isNotEmpty() && values.size.rem(ncol) == 0) {
-        "Number of values ${values.size} is not divisible by number of columns $ncol"
+    if (!(header.isNotEmpty() && values.size.rem(ncol) == 0)) {
+        throw WrongNumberOfValuesException(values.size, ncol)
     }
 
     val nrow = values.size / ncol
@@ -16,3 +22,9 @@ internal fun <T> withValuesImpl(header: List<String>, values: List<T>): List<Pai
         header[col] to colValues
     }
 }
+
+internal class WrongNumberOfValuesException(size: Int, ncol: Int) :
+    IllegalArgumentException(),
+    DataFrameError {
+    override val message = "Number of values $size is not divisible by number of columns $ncol"
+}
diff --git a/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/api/dataFrameOf.kt b/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/api/dataFrameOf.kt
index 30bd5befd9..5ee42eec9b 100644
--- a/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/api/dataFrameOf.kt
+++ b/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/api/dataFrameOf.kt
@@ -1,4 +1,3 @@
-@file:Suppress("INVISIBLE_REFERENCE", "INVISIBLE_MEMBER")
 package org.jetbrains.kotlinx.dataframe.plugin.impl.api
 
 import org.jetbrains.kotlin.fir.expressions.FirExpression
@@ -35,7 +34,7 @@ class DataFrameBuilderInvoke0 : AbstractSchemaModificationInterpreter() {
     val Arguments.values: FirVarargArgumentsExpression by arg(lens = Interpreter.Id)
 
     override fun Arguments.interpret(): PluginDataFrameSchema {
-        val columns = withValuesImpl(receiver.header, values.arguments).map { (name, values) ->
+        val columns = (receiver.header to values.arguments).withValuesImpl().map { (name, values) ->
             val type = session.typeContext.commonSuperTypeOrNull(values.map { it.resolvedType }) ?: error("$name $values")
             simpleColumnOf(name, type)
         }