add example

examples/animal.go

@@ -0,0 +1,9 @@
+package animal
+
+//go:generate go run github.com/andreykaipov/funcopgen -type=Animal -prefix=With -factory -unexported
+
+type Animal struct {
+	Surname string
+	Color   string
+	cute    bool
+}

examples/zz_generated.animal_funcop.go

@@ -0,0 +1,35 @@
+// This file has been automatically generated. Don't edit it.
+
+package animal
+
+import ()
+
+type Option func(*Animal)
+
+func NewAnimal(opts ...Option) *Animal {
+	o := &Animal{}
+
+	for _, opt := range opts {
+		opt(o)
+	}
+
+	return o
+}
+
+func WithColor(x string) Option {
+	return func(o *Animal) {
+		o.Color = x
+	}
+}
+
+func WithSurname(x string) Option {
+	return func(o *Animal) {
+		o.Surname = x
+	}
+}
+
+func WithCute(x bool) Option {
+	return func(o *Animal) {
+		o.cute = x
+	}
+}