example_value_test.go

Documentation: flag

		 1  // Copyright 2018 The Go Authors. All rights reserved.
		 2  // Use of this source code is governed by a BSD-style
		 3  // license that can be found in the LICENSE file.
		 4  
		 5  package flag_test
		 6  
		 7  import (
		 8  	"flag"
		 9  	"fmt"
		10  	"net/url"
		11  )
		12  
		13  type URLValue struct {
		14  	URL *url.URL
		15  }
		16  
		17  func (v URLValue) String() string {
		18  	if v.URL != nil {
		19  		return v.URL.String()
		20  	}
		21  	return ""
		22  }
		23  
		24  func (v URLValue) Set(s string) error {
		25  	if u, err := url.Parse(s); err != nil {
		26  		return err
		27  	} else {
		28  		*v.URL = *u
		29  	}
		30  	return nil
		31  }
		32  
		33  var u = &url.URL{}
		34  
		35  func ExampleValue() {
		36  	fs := flag.NewFlagSet("ExampleValue", flag.ExitOnError)
		37  	fs.Var(&URLValue{u}, "url", "URL to parse")
		38  
		39  	fs.Parse([]string{"-url", "https://golang.org/pkg/flag/"})
		40  	fmt.Printf(`{scheme: %q, host: %q, path: %q}`, u.Scheme, u.Host, u.Path)
		41  
		42  	// Output:
		43  	// {scheme: "https", host: "golang.org", path: "/pkg/flag/"}
		44  }
		45
View as plain text