IfSet and IfSetOtherwise

README.md

@@ -146,6 +146,24 @@ func main() {
         </td>
         <td><code><code>Optional[T]</code></code></td>
     </tr>
+    <tr>
+        <td>
+            <code>IfSet(f func(v T), notPresent func())</code><br>
+            if the value was set and is present, calls the supplied function with the value<br>
+            if the value was set but is not present, calls the supplied notPresent function<br>
+            otherwise, does nothing
+        </td>
+        <td><code>Optional[T]</code></td>
+    </tr>
+    <tr>
+        <td>
+            <code>IfSetOtherwise(f func(v T), notPresent func(), other func())</code><br>
+            if the value was set and is present, calls the supplied function with the value<br>
+            if the value was set but is not present, calls the supplied notPresent function<br>
+            otherwise, calls the other func
+        </td>
+        <td><code><code>Optional[T]</code></code></td>
+    </tr>
     <tr>
         <td>
             <code>OrElse(other T)</code><br>

optional.go

@@ -124,17 +124,47 @@ func (o *Optional[T]) Clear() Optional[T] {
 
 // IfPresent if the value is present, calls the supplied function with the value, otherwise does nothing
 func (o Optional[T]) IfPresent(f func(v T)) Optional[T] {
-	if o.present {
+	if o.present && f != nil {
 		f(o.value)
 	}
 	return o
 }
 
 // IfPresentOtherwise if the value is present, calls the supplied function with the value, otherwise calls the other function
 func (o Optional[T]) IfPresentOtherwise(f func(v T), other func()) Optional[T] {
-	if o.present {
+	if o.present && f != nil {
 		f(o.value)
-	} else {
+	} else if !o.present && other != nil {
+		other()
+	}
+	return o
+}
+
+// IfSet if the value was set and is present, calls the supplied function with the value
+//
+// if the value was set but is not present, calls the supplied notPresent function
+//
+// otherwise, does nothing
+func (o Optional[T]) IfSet(f func(v T), notPresent func()) Optional[T] {
+	if o.set && o.present && f != nil {
+		f(o.value)
+	} else if o.set && !o.present && notPresent != nil {
+		notPresent()
+	}
+	return o
+}
+
+// IfSetOtherwise if the value was set and is present, calls the supplied function with the value
+//
+// if the value was set but is not present, calls the supplied notPresent function
+//
+// otherwise, calls the other func
+func (o Optional[T]) IfSetOtherwise(f func(v T), notPresent func(), other func()) Optional[T] {
+	if o.set && o.present && f != nil {
+		f(o.value)
+	} else if o.set && !o.present && notPresent != nil {
+		notPresent()
+	} else if !o.set && !o.present && other != nil {
 		other()
 	}
 	return o

optional_test.go

@@ -151,6 +151,82 @@ func TestOptional_IfPresentOtherwise(t *testing.T) {
 	require.True(t, calledOther)
 }
 
+func TestOptional_IfSet(t *testing.T) {
+	o := EmptyString()
+	o.OrElseSet("aaa")
+	setCalled := false
+	notPresentCalled := false
+	value := ""
+	setFn := func(v string) {
+		setCalled = true
+		value = v
+	}
+	notPresentFn := func() {
+		notPresentCalled = true
+	}
+	o.IfSet(setFn, notPresentFn)
+	require.True(t, setCalled)
+	require.Equal(t, "aaa", value)
+	require.False(t, notPresentCalled)
+
+	setCalled = false
+	notPresentCalled = false
+	o.Clear()
+	err := o.UnmarshalJSON([]byte(`null`))
+	require.NoError(t, err)
+	o.IfSet(setFn, notPresentFn)
+	require.False(t, setCalled)
+	require.True(t, notPresentCalled)
+}
+
+func TestOptional_IfSetOtherwise(t *testing.T) {
+	type oStruct struct {
+		Foo Optional[string]
+	}
+	setCalled := false
+	notPresentCalled := false
+	otherCalled := false
+	setFn := func(v string) {
+		setCalled = true
+	}
+	notPresentFn := func() {
+		notPresentCalled = true
+	}
+	otherFn := func() {
+		otherCalled = true
+	}
+
+	strc := &oStruct{}
+	err := json.Unmarshal([]byte(`{}`), strc)
+	require.NoError(t, err)
+	strc.Foo.IfSetOtherwise(setFn, notPresentFn, otherFn)
+	require.False(t, setCalled)
+	require.False(t, notPresentCalled)
+	require.True(t, otherCalled)
+
+	setCalled = false
+	notPresentCalled = false
+	otherCalled = false
+	strc = &oStruct{}
+	err = json.Unmarshal([]byte(`{"Foo":null}`), strc)
+	require.NoError(t, err)
+	strc.Foo.IfSetOtherwise(setFn, notPresentFn, otherFn)
+	require.False(t, setCalled)
+	require.True(t, notPresentCalled)
+	require.False(t, otherCalled)
+
+	setCalled = false
+	notPresentCalled = false
+	otherCalled = false
+	strc = &oStruct{}
+	err = json.Unmarshal([]byte(`{"Foo":"abc"}`), strc)
+	require.NoError(t, err)
+	strc.Foo.IfSetOtherwise(setFn, notPresentFn, otherFn)
+	require.True(t, setCalled)
+	require.False(t, notPresentCalled)
+	require.False(t, otherCalled)
+}
+
 func TestOptional_OrElse(t *testing.T) {
 	o := Empty[string]()
 	v := o.OrElse("bbb")
@@ -391,6 +467,7 @@ func TestOptional_Scan(t *testing.T) {
 	require.False(t, o5.IsPresent())
 	require.False(t, o5.WasSet())
 	err = o5.Scan(nil)
+	require.NoError(t, err)
 	require.False(t, o5.IsPresent())
 	require.True(t, o5.WasSet())
 }