Support UnwrapAsPtr() method to unwrap the Option value as a pointer

Fix #25

Signed-off-by: moznion <[email protected]>

examples_test.go

@@ -85,6 +85,26 @@ func ExampleOption_Unwrap() {
 	// <nil>
 }
 
+func ExampleOption_UnwrapAsPtr() {
+	fmt.Printf("%v\n", *Some[int](12345).UnwrapAsPtr())
+	fmt.Printf("%v\n", None[int]().UnwrapAsPtr())
+	fmt.Printf("%v\n", None[*int]().UnwrapAsPtr())
+
+	num := 123
+	fmt.Printf("%v\n", *FromNillable[int](&num).UnwrapAsPtr())
+	fmt.Printf("%v\n", FromNillable[int](nil).UnwrapAsPtr())
+	fmt.Printf("%v\n", **PtrFromNillable[int](&num).UnwrapAsPtr()) // NOTE: this dereferences tha unwrapped value
+	fmt.Printf("%v\n", PtrFromNillable[int](nil).UnwrapAsPtr())
+	// Output:
+	// 12345
+	// <nil>
+	// <nil>
+	// 123
+	// <nil>
+	// 123
+	// <nil>
+}
+
 func ExampleOption_Take() {
 	some := Some[int](1)
 	v, err := some.Take()

option.go

@@ -73,6 +73,16 @@ func (o Option[T]) Unwrap() T {
 	return o[value]
 }
 
+// UnwrapAsPtr returns the contained value in receiver Option as a pointer.
+// This is similar to `Unwrap()` method but the difference is this method returns a pointer value instead of the actual value.
+// If the receiver Option value is None, this method returns nil.
+func (o Option[T]) UnwrapAsPtr() *T {
+	if o.IsNone() {
+		return nil
+	}
+	return &o[value]
+}
+
 // Take takes the contained value in Option.
 // If Option value is Some, this returns the value that is contained in Option.
 // On the other hand, this returns an ErrNoneValueTaken as the second return value.

option_test.go

@@ -45,6 +45,21 @@ func TestOption_Unwrap(t *testing.T) {
 	assert.Nil(t, PtrFromNillable[int](nil).Unwrap())
 }
 
+func TestOption_UnwrapAsPointer(t *testing.T) {
+	str := "foo"
+	refStr := &str
+	assert.EqualValues(t, &str, Some[string](str).UnwrapAsPtr())
+	assert.EqualValues(t, &refStr, Some[*string](refStr).UnwrapAsPtr())
+	assert.Nil(t, None[string]().UnwrapAsPtr())
+	assert.Nil(t, None[*string]().UnwrapAsPtr())
+
+	i := 123
+	assert.Equal(t, &i, FromNillable[int](&i).UnwrapAsPtr())
+	assert.Nil(t, FromNillable[int](nil).UnwrapAsPtr())
+	assert.Equal(t, &i, *PtrFromNillable[int](&i).UnwrapAsPtr())
+	assert.Nil(t, PtrFromNillable[int](nil).UnwrapAsPtr())
+}
+
 func TestOption_Take(t *testing.T) {
 	v, err := Some[int](123).Take()
 	assert.NoError(t, err)