[OPS] Added a type constraint in the TF records parsing ops.

Author: eaplatanios

modules/api/src/main/scala/org/platanios/tensorflow/api/core/types/package.scala

@@ -158,6 +158,7 @@ package object types {
   type UByteOrUShort = Union[UByte]#or[UShort]#create
   type Integer = Union[Byte]#or[Short]#or[Int]#or[Long]#or[UByte]#or[UShort]#or[UInt]#or[ULong]#create
   type StringOrInteger = Union[String]#or[Byte]#or[Short]#or[Int]#or[Long]#or[UByte]#or[UShort]#or[UInt]#or[ULong]#create
+  type StringOrFloatOrLong = Union[String]#or[Float]#or[Long]#create
   type Real = Union[TruncatedHalf]#or[Half]#or[Float]#or[Double]#or[Byte]#or[Short]#or[Int]#or[Long]#or[UByte]#or[UShort]#or[UInt]#or[ULong]#create
   type Complex = Union[ComplexFloat]#or[ComplexDouble]#create
   type NotQuantized = Union[TruncatedHalf]#or[Half]#or[Float]#or[Double]#or[Byte]#or[Short]#or[Int]#or[Long]#or[UByte]#or[UShort]#or[UInt]#or[ULong]#or[ComplexFloat]#or[ComplexDouble]#create
@@ -177,7 +178,8 @@ package object types {
   type IsIntOrLongOrUByte[T] = Contains[T, IntOrLongOrUByte]
   type IsIntOrUInt[T] = Contains[T, Integer]
   type IsUByteOrUShort[T] = Contains[T, UByteOrUShort]
-  type IsStringOrIntOrUInt[T] = Contains[T, StringOrInteger]
+  type IsStringOrInteger[T] = Contains[T, StringOrInteger]
+  type IsStringOrFloatOrLong[T] = Contains[T, StringOrFloatOrLong]
   type IsReal[T] = Contains[T, Real]
   type IsComplex[T] = Contains[T, Complex]
   type IsNotQuantized[T] = Contains[T, NotQuantized]
@@ -233,8 +235,12 @@ package object types {
     def apply[T: IsUByteOrUShort]: IsUByteOrUShort[T] = implicitly[IsUByteOrUShort[T]]
   }
 
-  object IsStringOrIntOrUInt {
-    def apply[T: IsStringOrIntOrUInt]: IsStringOrIntOrUInt[T] = implicitly[IsStringOrIntOrUInt[T]]
+  object IsStringOrInteger {
+    def apply[T: IsStringOrInteger]: IsStringOrInteger[T] = implicitly[IsStringOrInteger[T]]
+  }
+
+  object IsStringOrFloatOrLong {
+    def apply[T: IsStringOrFloatOrLong]: IsStringOrFloatOrLong[T] = implicitly[IsStringOrFloatOrLong[T]]
   }
 
   object IsReal {

modules/api/src/main/scala/org/platanios/tensorflow/api/ops/Parsing.scala

@@ -272,7 +272,7 @@ object Parsing extends Parsing {
     * @param  defaultValue Value to be used if an example is missing this feature. It must match the specified `shape`.
     * @tparam T Data type of the input feature.
     */
-  case class FixedLengthFeature[T: TF](
+  case class FixedLengthFeature[T: TF : IsStringOrFloatOrLong](
       key: String,
       shape: Shape,
       defaultValue: Option[Tensor[T]] = None
@@ -285,7 +285,7 @@ object Parsing extends Parsing {
     *
     * @param  dataType Data type of the input feature.
     */
-  case class VariableLengthFeature[T: TF](
+  case class VariableLengthFeature[T: TF : IsStringOrFloatOrLong](
       key: String,
       dataType: DataType[T]
   ) extends Feature
@@ -341,7 +341,7 @@ object Parsing extends Parsing {
     *                       position. If so, we skip sorting.
     * @tparam T Data type of the `valueKey` feature.
     */
-  case class SparseFeature[T: TF](
+  case class SparseFeature[T: TF : IsStringOrFloatOrLong](
       indexKeys: Seq[String],
       valueKey: String,
       size: Seq[Long],

modules/api/src/main/scala/org/platanios/tensorflow/api/package.scala

@@ -212,7 +212,8 @@ package object api extends implicits.Implicits with Documentation {
   type IsIntOrLongOrHalfOrFloatOrDouble[T] = core.types.IsIntOrLongOrHalfOrFloatOrDouble[T]
   type IsIntOrLongOrUByte[T] = core.types.IsIntOrLongOrUByte[T]
   type IsIntOrUInt[T] = core.types.IsIntOrUInt[T]
-  type IsStringOrIntOrUInt[T] = core.types.IsStringOrIntOrUInt[T]
+  type IsStringOrInteger[T] = core.types.IsStringOrInteger[T]
+  type IsStringOrFloatOrLong[T] = core.types.IsStringOrFloatOrLong[T]
   type IsReal[T] = core.types.IsReal[T]
   type IsComplex[T] = core.types.IsComplex[T]
   type IsNotQuantized[T] = core.types.IsNotQuantized[T]
@@ -231,7 +232,7 @@ package object api extends implicits.Implicits with Documentation {
   val IsIntOrLongOrHalfOrFloatOrDouble: core.types.IsIntOrLongOrHalfOrFloatOrDouble.type = core.types.IsIntOrLongOrHalfOrFloatOrDouble
   val IsIntOrLongOrUByte              : core.types.IsIntOrLongOrUByte.type               = core.types.IsIntOrLongOrUByte
   val IsIntOrUInt                     : core.types.IsIntOrUInt.type                      = core.types.IsIntOrUInt
-  val IsStringOrIntOrUInt             : core.types.IsStringOrIntOrUInt.type              = core.types.IsStringOrIntOrUInt
+  val IsStringOrFloatOrLong           : core.types.IsStringOrFloatOrLong.type            = core.types.IsStringOrFloatOrLong
   val IsReal                          : core.types.IsReal.type                           = core.types.IsReal
   val IsComplex                       : core.types.IsComplex.type                        = core.types.IsComplex
   val IsNotQuantized                  : core.types.IsNotQuantized.type                   = core.types.IsNotQuantized