Evaluate FHIR.decimal.value directly to a System.Decimal

interpreter/operator_type.go

@@ -248,15 +248,18 @@ func evalToDecimalString(m model.IUnaryExpression, opObj result.Value) (result.V
 	if err != nil {
 		return result.Value{}, err
 	}
+	return toDecimalFromString(op)
+}
 
+func toDecimalFromString(s string) (result.Value, error) {
 	// Check that the string meets the CQL decimal spec requirements.
-	found := decimalStringRegex.FindString(op)
-	if found == "" || found != op {
+	found := decimalStringRegex.FindString(s)
+	if found == "" || found != s {
 		return result.New(nil)
 	}
 
 	// ParseFloat works for every string that meets the CQL spec.
-	f, err := strconv.ParseFloat(op, 64)
+	f, err := strconv.ParseFloat(s, 64)
 	if err != nil {
 		return result.Value{}, err
 	}

interpreter/property.go

@@ -157,13 +157,25 @@ func (i *interpreter) protoProperty(source result.Named, property string, static
 	// For .value properties on FHIR.dateTime, FHIR.time, FHIR.date, the result type is expected to be
 	// a System.DateTime, System.Time, System.Date. This is not how the data is represented in the
 	// FHIR proto data model, so we must catch this case and apply manual conversion.
-
 	if property == "value" && (source.RuntimeType.Equal(&types.Named{TypeName: "FHIR.dateTime"}) ||
 		source.RuntimeType.Equal(&types.Named{TypeName: "FHIR.time"}) ||
 		source.RuntimeType.Equal(&types.Named{TypeName: "FHIR.date"})) {
 		return handleDateTimeValueProperty(source.Value, property, i.evaluationTimestamp.Location())
 	}
 
+	// For .value properties on FHIR.decimal, the result type is expected to be a System.Decimal, but
+	// this is not how the data is represented in the FHIR proto data model, so we must catch this
+	// case and apply manual conversion. We may wish to consider applying a parser insertion in the
+	// future.
+	if property == "value" && source.RuntimeType.Equal(&types.Named{TypeName: "FHIR.decimal"}) {
+		d, ok := source.Value.(*d4pb.Decimal)
+		if !ok {
+			return result.Value{}, fmt.Errorf("Unable to convert result type of FHIR.decimal to a *d4pb.decimal")
+		}
+		valueStr := d.Value
+		return toDecimalFromString(valueStr)
+	}
+
 	protoProperty, err := protoFieldFromJSONName(source.Value, property)
 	if err != nil {
 		return result.Value{}, err

tests/enginetests/property_test.go

@@ -338,6 +338,16 @@ func TestProperty(t *testing.T) {
 			},
 			wantResult: newOrFatal(t, result.Named{Value: &d4pb.String{Value: "obsValue"}, RuntimeType: &types.Named{TypeName: "FHIR.string"}}),
 		},
+		{
+			name: "FHIR.decimal.value returns a System.Decimal",
+			cql: dedent.Dedent(`
+					define FirstObservation: First([Observation])
+					define TESTRESULT: (FirstObservation.value as FHIR.Quantity).value.value`),
+			resources: []*r4pb.ContainedResource{
+				containedFromObservation(&r4observationpb.Observation{Value: &r4observationpb.Observation_ValueX{Choice: &r4observationpb.Observation_ValueX_Quantity{Quantity: &d4pb.Quantity{Value: &d4pb.Decimal{Value: "100.1"}}}}}),
+			},
+			wantResult: newOrFatal(t, 100.1),
+		},
 		{
 			name: "dateTime inside oneof returns dateTime proto",
 			cql: dedent.Dedent(`