Update comments and korro, clarify TODO

Author: Kopilov

dataframe-arrow/src/main/kotlin/org/jetbrains/kotlinx/dataframe/io/ArrowWriterImpl.kt

@@ -89,21 +89,17 @@ internal class ArrowWriterImpl(
         return when (targetFieldType) {
             ArrowType.Utf8() -> column.map { it?.toString() }
             ArrowType.LargeUtf8() -> column.map { it?.toString() }
-            ArrowType.Binary(), ArrowType.LargeBinary() -> throw NotImplementedError("Saving var binary is currently not implemented")
             ArrowType.Bool() -> column.convertToBoolean()
             ArrowType.Int(8, true) -> column.convertToByte()
             ArrowType.Int(16, true) -> column.convertToShort()
             ArrowType.Int(32, true) -> column.convertToInt()
             ArrowType.Int(64, true) -> column.convertToLong()
-//            ArrowType.Int(8, false), ArrowType.Int(16, false), ArrowType.Int(32, false), ArrowType.Int(64, false) -> todo
             is ArrowType.Decimal -> column.convertToBigDecimal()
             ArrowType.FloatingPoint(FloatingPointPrecision.SINGLE) -> column.convertToDouble().convertToFloat() // Use [convertToDouble] as locale logic step
             ArrowType.FloatingPoint(FloatingPointPrecision.DOUBLE) -> column.convertToDouble()
             ArrowType.Date(DateUnit.DAY) -> column.convertToLocalDate()
             ArrowType.Date(DateUnit.MILLISECOND) -> column.convertToLocalDateTime()
             is ArrowType.Time -> column.convertToLocalTime()
-//            is ArrowType.Duration -> todo
-//            is ArrowType.Struct -> todo
             else -> {
                 throw NotImplementedError("Saving ${targetFieldType.javaClass.canonicalName} is currently not implemented")
             }
@@ -114,17 +110,11 @@ internal class ArrowWriterImpl(
         when (vector) {
             is VarCharVector -> column.convertToString().forEachIndexed { i, value -> value?.let { vector.set(i, Text(value)); value } ?: vector.setNull(i) }
             is LargeVarCharVector -> column.convertToString().forEachIndexed { i, value -> value?.let { vector.set(i, Text(value)); value } ?: vector.setNull(i) }
-//            is VarBinaryVector -> todo
-//            is LargeVarBinaryVector -> todo
             is BitVector -> column.convertToBoolean().forEachIndexed { i, value -> value?.let { vector.set(i, value.compareTo(false)); value } ?: vector.setNull(i) }
             is TinyIntVector -> column.convertToInt().forEachIndexed { i, value -> value?.let { vector.set(i, value); value } ?: vector.setNull(i) }
             is SmallIntVector -> column.convertToInt().forEachIndexed { i, value -> value?.let { vector.set(i, value); value } ?: vector.setNull(i) }
             is IntVector -> column.convertToInt().forEachIndexed { i, value -> value?.let { vector.set(i, value); value } ?: vector.setNull(i) }
             is BigIntVector -> column.convertToLong().forEachIndexed { i, value -> value?.let { vector.set(i, value); value } ?: vector.setNull(i) }
-//            is UInt1Vector -> todo
-//            is UInt2Vector -> todo
-//            is UInt4Vector -> todo
-//            is UInt8Vector -> todo
             is DecimalVector -> column.convertToBigDecimal().forEachIndexed { i, value -> value?.let { vector.set(i, value); value } ?: vector.setNull(i) }
             is Decimal256Vector -> column.convertToBigDecimal().forEachIndexed { i, value -> value?.let { vector.set(i, value); value } ?: vector.setNull(i) }
             is Float8Vector -> column.convertToDouble().forEachIndexed { i, value -> value?.let { vector.set(i, value); value } ?: vector.setNull(i) }
@@ -133,13 +123,12 @@ internal class ArrowWriterImpl(
             is DateDayVector -> column.convertToLocalDate().forEachIndexed { i, value -> value?.let { vector.set(i, (value.toJavaLocalDate().toEpochDay()).toInt()); value } ?: vector.setNull(i) }
             is DateMilliVector -> column.convertToLocalDateTime().forEachIndexed { i, value -> value?.let { vector.set(i, value.toInstant(
                 TimeZone.UTC).toEpochMilliseconds()); value } ?: vector.setNull(i) }
-//            is DurationVector -> todo
             is TimeNanoVector -> column.convertToLocalTime().forEachIndexed { i, value -> value?.let { vector.set(i, value.toNanoOfDay()); value } ?: vector.setNull(i) }
             is TimeMicroVector -> column.convertToLocalTime().forEachIndexed { i, value -> value?.let { vector.set(i, value.toNanoOfDay() / 1000); value } ?: vector.setNull(i) }
             is TimeMilliVector -> column.convertToLocalTime().forEachIndexed { i, value -> value?.let { vector.set(i, (value.toNanoOfDay() / 1000 / 1000).toInt()); value } ?: vector.setNull(i) }
             is TimeSecVector -> column.convertToLocalTime().forEachIndexed { i, value -> value?.let { vector.set(i, (value.toNanoOfDay() / 1000 / 1000 / 1000).toInt()); value } ?: vector.setNull(i) }
-//            is StructVector -> todo
             else -> {
+                // TODO implement other vector types from [readField] (VarBinaryVector, UIntVector, DurationVector, StructVector) and may be others (ListVector, FixedSizeListVector etc)
                 throw NotImplementedError("Saving to ${vector.javaClass.canonicalName} is currently not implemented")
             }
         }

dataframe-arrow/src/main/kotlin/org/jetbrains/kotlinx/dataframe/io/arrowReadingImpl.kt

@@ -174,7 +174,7 @@ private inline fun <reified T> List<T?>.withTypeNullable(
     return this to typeOf<T>().withNullability(nullable)
 }
 
-internal fun readField(root: VectorSchemaRoot, field: Field, nullability: NullabilityOptions): AnyBaseCol {
+private fun readField(root: VectorSchemaRoot, field: Field, nullability: NullabilityOptions): AnyBaseCol {
     try {
         val range = 0 until root.rowCount
         val (list, type) = when (val vector = root.getVector(field)) {
@@ -216,7 +216,7 @@ internal fun readField(root: VectorSchemaRoot, field: Field, nullability: Nullab
 /**
  * Read [Arrow interprocess streaming format](https://arrow.apache.org/docs/java/ipc.html#writing-and-reading-streaming-format) data from existing [channel]
  */
-public fun DataFrame.Companion.readArrowIPCImpl(
+internal fun DataFrame.Companion.readArrowIPCImpl(
     channel: ReadableByteChannel,
     allocator: RootAllocator = Allocator.ROOT,
     nullability: NullabilityOptions = NullabilityOptions.Infer,
@@ -237,7 +237,7 @@ public fun DataFrame.Companion.readArrowIPCImpl(
 /**
  * Read [Arrow random access format](https://arrow.apache.org/docs/java/ipc.html#writing-and-reading-random-access-files) data from existing [channel]
  */
-public fun DataFrame.Companion.readArrowFeatherImpl(
+internal fun DataFrame.Companion.readArrowFeatherImpl(
     channel: SeekableByteChannel,
     allocator: RootAllocator = Allocator.ROOT,
     nullability: NullabilityOptions = NullabilityOptions.Infer,

tests/src/test/kotlin/org/jetbrains/kotlinx/dataframe/samples/api/Write.kt

@@ -204,7 +204,7 @@ class Write : TestBase() {
                     strictType = true,
                     strictNullable = false
                 ),
-                // Specify warning subscriber
+                // Specify mismatch subscriber
                 writeMismatchMessage
             ).use { writer ->
                 // Save to any format and sink, like in previous example