def isSupported()

in spark/src/main/scala/org/apache/comet/expressions/CometCast.scala [54:109]
52 lines of code
23 McCabe index (conditional complexity)

  def isSupported(
      fromType: DataType,
      toType: DataType,
      timeZoneId: Option[String],
      evalMode: CometEvalMode.Value): SupportLevel = {

    if (fromType == toType) {
      return Compatible()
    }

    (fromType, toType) match {
      case (dt: DataType, _) if dt.typeName == "timestamp_ntz" =>
        // https://github.com/apache/datafusion-comet/issues/378
        toType match {
          case DataTypes.TimestampType | DataTypes.DateType | DataTypes.StringType =>
            Incompatible()
          case _ =>
            Unsupported
        }
      case (_: DecimalType, _: DecimalType) =>
        Compatible()
      case (DataTypes.StringType, _) =>
        canCastFromString(toType, timeZoneId, evalMode)
      case (_, DataTypes.StringType) =>
        canCastToString(fromType, timeZoneId, evalMode)
      case (DataTypes.TimestampType, _) =>
        canCastFromTimestamp(toType)
      case (_: DecimalType, _) =>
        canCastFromDecimal(toType)
      case (DataTypes.BooleanType, _) =>
        canCastFromBoolean(toType)
      case (DataTypes.ByteType, _) =>
        canCastFromByte(toType)
      case (DataTypes.ShortType, _) =>
        canCastFromShort(toType)
      case (DataTypes.IntegerType, _) =>
        canCastFromInt(toType)
      case (DataTypes.LongType, _) =>
        canCastFromLong(toType)
      case (DataTypes.FloatType, _) =>
        canCastFromFloat(toType)
      case (DataTypes.DoubleType, _) =>
        canCastFromDouble(toType)
      case (from_struct: StructType, to_struct: StructType) =>
        from_struct.fields.zip(to_struct.fields).foreach { case (a, b) =>
          isSupported(a.dataType, b.dataType, timeZoneId, evalMode) match {
            case Compatible(_) =>
            // all good
            case other =>
              return other
          }
        }
        Compatible()
      case _ => Unsupported
    }
  }