Add a new "New" method to the Interface

This is needed mainly to create a new set from other methods where we do not have any knowledge about the underlying struct. Also this will be helpful for #13

set.go

@@ -9,6 +9,7 @@ package set
 
 // Interface describing a Set. Sets are an unordered, unique list of values.
 type Interface interface {
+	New(items ...interface{}) Interface
 	Add(items ...interface{})
 	Remove(items ...interface{})
 	Pop() interface{}

set_nots.go

@@ -1,8 +1,8 @@
 package set
 
 import (
-  "fmt"
-  "strings"
+	"fmt"
+	"strings"
 )
 
 // Provides a common set baseline for both threadsafe and non-ts Sets.
@@ -26,6 +26,13 @@ func NewNonTS(items ...interface{}) *SetNonTS {
 	return s
 }
 
+// New creates and initalizes a new Set interface. It accepts a variable
+// number of arguments to populate the initial set. If nothing is passed a
+// zero size Set based on the struct is created.
+func (s *set) New(items ...interface{}) Interface {
+	return NewNonTS(items...)
+}
+
 // Add includes the specified items (one or more) to the set. The underlying
 // Set s is modified. If passed nothing it silently returns.
 func (s *set) Add(items ...interface{}) {

set_ts.go

@@ -21,6 +21,10 @@ func New(items ...interface{}) *Set {
 	return s
 }
 
+// func (s *set) New(items ...interface{}) Interface {
+// 	return s.New(items...)
+// }
+
 // Add includes the specified items (one or more) to the set. The underlying
 // Set s is modified. If passed nothing it silently returns.
 func (s *Set) Add(items ...interface{}) {
@@ -185,4 +189,3 @@ func (s *Set) Merge(t Interface) {
 		return true
 	})
 }
-

set_ts_test.go

@@ -13,6 +13,10 @@ func TestSet_New(t *testing.T) {
 		t.Error("New: calling without any parameters should create a set with zero size")
 	}
 
+	u := s.New()
+	if u.Size() != 0 {
+		t.Error("New: creating a new set via s.New() should create a set with zero size")
+	}
 }
 
 func TestSet_New_parameters(t *testing.T) {