add example to inject env into stuct fields

README.md

@@ -86,6 +86,20 @@ func init() {
 	env.Var(&intervalEnv, "delta_t", "comma-separated list of intervals to use between events")
 }
 
+type Config struct {
+	Host string
+	Port string
+	// ....
+}
+
+func init() {
+	cfg := new(Config)
+	// Tie the environ to the struct fields and
+	// set a usage messages.
+	env.StringVar(&cfg.Host, "host", "localhost", "App host name")
+	env.StringVar(&cfg.Port, "port", "443", "App port")
+}
+
 func main() {
 	os.Setenv("DELTA_T", "1s,2m,3h")
 

example_struct_test.go

@@ -0,0 +1,31 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package env_test
+
+import (
+	"fmt"
+
+	"github.com/shaj13/env"
+)
+
+type Config struct {
+	Host string
+	Port string
+	// ....
+}
+
+func Example_struct() {
+	cfg := new(Config)
+
+	es := env.NewEnvSet("app", env.ExitOnError)
+	es.StringVar(&cfg.Host, "host", "localhost", "App host name")
+	es.StringVar(&cfg.Port, "port", "443", "App port")
+
+	es.Parse([]string{"APP_HOST=env.localhost"})
+	fmt.Printf(`%s:%s`, cfg.Host, cfg.Port)
+
+	// Output:
+	// env.localhost:443
+}