Split up filter documentation into basic and advanced development

examples/SimpleAlgorithm.cxx

 #include <vtkm/worklet/WorkletMapField.h>
 
+#include <vtkm/filter/FilterField.h>
+
 #include <vtkm/cont/Invoker.h>
 
+#include <vtkm/cont/testing/MakeTestDataSet.h>
 #include <vtkm/cont/testing/Testing.h>
 
 namespace
@@ -13,7 +16,8 @@ constexpr vtkm::Id ARRAY_SIZE = 10;
 //// BEGIN-EXAMPLE SimpleWorklet.cxx
 ////
 //// LABEL Inherit
-struct PoundsPerSquareInchToNewtonsPerSquareMeter : vtkm::worklet::WorkletMapField
+struct PoundsPerSquareInchToNewtonsPerSquareMeterWorklet
+  : vtkm::worklet::WorkletMapField
 {
   //// LABEL ControlSignature
   //// BEGIN-EXAMPLE ControlSignature.cxx
@@ -35,7 +39,22 @@ struct PoundsPerSquareInchToNewtonsPerSquareMeter : vtkm::worklet::WorkletMapFie
   {
     //// END-EXAMPLE WorkletOperator.cxx
     // 1 psi = 6894.76 N/m^2
+    //// PAUSE-EXAMPLE
+    // The following line can create a warning when converting the literal
+    // to a float, even though it is clear that I want the casting. Rather
+    // then add the confusing code to handle all cases, just suppress the
+    // warning.
+#ifdef VTKM_MSVC
+#pragma warning(push)
+#pragma warning(disable : 4305)
+#endif
+    //// RESUME-EXAMPLE
     nsm = T(6894.76) * psi;
+    //// PAUSE-EXAMPLE
+#ifdef VTKM_MSVC
+#pragma warning(pop)
+#endif
+    //// RESUME-EXAMPLE
     //// LABEL OperatorEnd
   }
 };
@@ -60,15 +79,112 @@ void DemoWorklet()
 
   vtkm::cont::ArrayHandle<vtkm::FloatDefault> nsmArray;
   //// LABEL Call
-  invoke(PoundsPerSquareInchToNewtonsPerSquareMeter{}, psiArray, nsmArray);
+  invoke(PoundsPerSquareInchToNewtonsPerSquareMeterWorklet{}, psiArray, nsmArray);
   ////
   //// END-EXAMPLE WorkletInvoke.cxx
   ////
 }
 
+} // anonymous namespace
+
+////
+//// BEGIN-EXAMPLE SimpleField.cxx
+////
+namespace vtkm
+{
+namespace filter
+{
+
+class PoundsPerSquareInchToNewtonsPerSquareMeterFilter
+  : public vtkm::filter::FilterField<
+      PoundsPerSquareInchToNewtonsPerSquareMeterFilter>
+{
+public:
+  VTKM_CONT PoundsPerSquareInchToNewtonsPerSquareMeterFilter();
+
+  template<typename ArrayHandleType, typename Policy>
+  VTKM_CONT vtkm::cont::DataSet DoExecute(
+    const vtkm::cont::DataSet& inDataSet,
+    const ArrayHandleType& inField,
+    const vtkm::filter::FieldMetadata& fieldMetadata,
+    vtkm::filter::PolicyBase<Policy>);
+};
+
+}
+} // namespace vtkm::filter
+////
+//// END-EXAMPLE SimpleField.cxx
+////
+
+////
+//// BEGIN-EXAMPLE SimpleFieldConstructor.cxx
+////
+VTKM_CONT vtkm::filter::PoundsPerSquareInchToNewtonsPerSquareMeterFilter::
+  PoundsPerSquareInchToNewtonsPerSquareMeterFilter()
+{
+  this->SetOutputFieldName("");
+}
+////
+//// END-EXAMPLE SimpleFieldConstructor.cxx
+////
+
+////
+//// BEGIN-EXAMPLE SimpleFieldDoExecute.cxx
+////
+template<typename ArrayHandleType, typename Policy>
+VTKM_CONT vtkm::cont::DataSet
+vtkm::filter::PoundsPerSquareInchToNewtonsPerSquareMeterFilter::DoExecute(
+  const vtkm::cont::DataSet& inDataSet,
+  const ArrayHandleType& inField,
+  const vtkm::filter::FieldMetadata& fieldMetadata,
+  vtkm::filter::PolicyBase<Policy>)
+{
+  //// LABEL CheckArray
+  VTKM_IS_ARRAY_HANDLE(ArrayHandleType);
+
+  using ValueType = typename ArrayHandleType::ValueType;
+
+  //// LABEL CreateOutputArray
+  vtkm::cont::ArrayHandle<ValueType> outField;
+
+  //// LABEL Invoke
+  this->Invoke(
+    PoundsPerSquareInchToNewtonsPerSquareMeterWorklet{}, inField, outField);
+
+  //// LABEL OutputName
+  std::string outFieldName = this->GetOutputFieldName();
+  if (outFieldName == "")
+  {
+    outFieldName = fieldMetadata.GetName() + "_N/M^2";
+  }
+
+  //// LABEL CreateResult
+  return vtkm::filter::CreateResult(
+    inDataSet, outField, outFieldName, fieldMetadata);
+}
+////
+//// END-EXAMPLE SimpleFieldDoExecute.cxx
+////
+
+namespace
+{
+
+void DemoFilter()
+{
+  vtkm::cont::testing::MakeTestDataSet makeData;
+  vtkm::cont::DataSet inData = makeData.Make3DExplicitDataSet0();
+
+  vtkm::filter::PoundsPerSquareInchToNewtonsPerSquareMeterFilter convertFilter;
+  convertFilter.SetActiveField("pointvar");
+  vtkm::cont::DataSet outData = convertFilter.Execute(inData);
+
+  VTKM_TEST_ASSERT(outData.HasPointField("pointvar_N/m^2"));
+}
+
 void Run()
 {
   DemoWorklet();
+  DemoFilter();
 }
 
 } // anonymous namespace