add reference struct

reference.go

@@ -0,0 +1,40 @@
+package forge
+
+import "errors"
+
+// Reference struct used for holding data neede for Reference data type
+type Reference struct {
+	section *Section
+	name    string
+}
+
+// NewReference will create and initialize a new Reference value
+func NewReference(name string, section *Section) *Reference {
+	return &Reference{
+		section: section,
+		name:    name,
+	}
+}
+
+func (reference *Reference) resolve() Value {
+	value, err := reference.section.Resolve(reference.name)
+	if err != nil {
+		value = NewNull()
+	}
+	return value
+}
+
+// GetType will simply return back REFERENCE
+func (reference *Reference) GetType() ValueType {
+	return REFERENCE
+}
+
+// GetValue will resolve and return the value from the underlying reference
+func (reference *Reference) GetValue() interface{} {
+	return reference.resolve().GetValue()
+}
+
+// UpdateValue will simply throw an error since it is not allowed for References
+func (reference *Reference) UpdateValue(value interface{}) error {
+	return errors.New("cannot update value of a reference")
+}