feat: Add ability to set Numbers to Fact Pointers (#495)

Add the ability to set a number to a Fact field pointer if the pointer
points to a number value.

Author: rlshumat

examples/NumberToPointer_test.go

@@ -0,0 +1,60 @@
+package examples
+
+import (
+	"testing"
+
+	"github.com/hyperjumptech/grule-rule-engine/ast"
+	"github.com/hyperjumptech/grule-rule-engine/builder"
+	"github.com/hyperjumptech/grule-rule-engine/engine"
+	"github.com/hyperjumptech/grule-rule-engine/pkg"
+	"github.com/stretchr/testify/assert"
+)
+
+const (
+	trainRule = `
+	rule TrainSpeedAdjust "Adjust Train speed based on passenger count" salience 10 {
+        when 
+            Train.PassengerCount > 50
+        then
+            Train.Speed = 75.45;
+			Train.Stops = Train.Stops - 1;
+			Retract("TrainSpeedAdjust");
+    }
+	`
+)
+
+type Train struct {
+	Speed          *float32
+	PassengerCount *uint16
+	Stops          *int64
+}
+
+func TestSetNumberToPointer(t *testing.T) {
+
+	speed := float32(204.31)
+	passengerCount := uint16(100)
+	stops := int64(3)
+	train := &Train{
+		Speed:          &speed,
+		PassengerCount: &passengerCount,
+		Stops:          &stops,
+	}
+
+	dataContext := ast.NewDataContext()
+	err := dataContext.Add("Train", train)
+	assert.NoError(t, err)
+
+	lib := ast.NewKnowledgeLibrary()
+	rb := builder.NewRuleBuilder(lib)
+	err = rb.BuildRuleFromResource("TestSetNumberToPointer", "0.1.1", pkg.NewBytesResource([]byte(trainRule)))
+	assert.NoError(t, err)
+	eng := &engine.GruleEngine{MaxCycle: 5}
+	kb, err := lib.NewKnowledgeBaseInstance("TestSetNumberToPointer", "0.1.1")
+	assert.NoError(t, err)
+	err = eng.Execute(dataContext, kb)
+	assert.NoError(t, err)
+
+	assert.Equal(t, int64(2), *train.Stops)
+	assert.Equal(t, uint16(100), *train.PassengerCount)
+	assert.Equal(t, float32(75.45), *train.Speed)
+}

model/GoDataAccessLayer.go

@@ -406,7 +406,10 @@ func (node *GoValueNode) SetObjectValueByField(field string, newValue reflect.Va
 		if pkg.IsNumber(fieldVal) && pkg.IsNumber(newValue) {
 
 			return SetNumberValue(fieldVal, newValue)
+		} else if pkg.IsPointerToNumber(fieldVal) && pkg.IsNumber(newValue) {
+			return SetNumberValue(fieldVal.Elem(), newValue)
 		}
+
 		fieldVal.Set(newValue)
 
 		return nil

pkg/reflectools.go

@@ -659,6 +659,11 @@ func IsNumber(val reflect.Value) bool {
 	}
 }
 
+// IsPointerToNumber will check a value if it is a pointer to a number eg, int, uint, or float
+func IsPointerToNumber(val reflect.Value) bool {
+	return IsNumber(GetValueElem(val))
+}
+
 // GetValueElem will return the value val contains if val is of Kind Interface or Pointer
 func GetValueElem(val reflect.Value) reflect.Value {
 	if val.Kind() == reflect.Pointer || val.Kind() == reflect.Interface {