go-arg/example_test.go

package arg

import (
	"fmt"
	"os"

	"github.com/alexflint/go-arg"
)

// This example demonstrates basic usage
func Example_Basic() {
	// These are the args you would pass in on the command line
	os.Args = []string{"./example", "--foo=hello", "--bar"}

	var args struct {
		Foo string
		Bar bool
	}
	arg.MustParse(&args)
	fmt.Println(args.Foo, args.Bar)
}

// This example demonstrates arguments that have default values
func Example_DefaultValues() {
	// These are the args you would pass in on the command line
	os.Args = []string{"--help"}

	var args struct {
		Foo string
		Bar bool
	}
	args.Foo = "default value"
	arg.MustParse(&args)
	fmt.Println(args.Foo, args.Bar)
}

// This example demonstrates arguments that are required
func Example_RequiredArguments() {
	// These are the args you would pass in on the command line
	os.Args = []string{"--foo=1", "--bar"}

	var args struct {
		Foo string `arg:"required"`
		Bar bool
	}
	arg.MustParse(&args)
}

// This example demonstrates positional arguments
func Example_PositionalArguments() {
	// These are the args you would pass in on the command line
	os.Args = []string{"./example", "in", "out1", "out2", "out3"}

	var args struct {
		Input  string   `arg:"positional"`
		Output []string `arg:"positional"`
	}
	arg.MustParse(&args)
	fmt.Println("Input:", args.Input)
	fmt.Println("Output:", args.Output)
}

// This example demonstrates arguments that have multiple values
func Example_MultipleValues() {
	// The args you would pass in on the command line
	os.Args = []string{"--help"}

	var args struct {
		Database string
		IDs      []int64
	}
	arg.MustParse(&args)
	fmt.Printf("Fetching the following IDs from %s: %q", args.Database, args.IDs)
}

// This example shows the usage string generated by go-arg
func Example_UsageString() {
	// These are the args you would pass in on the command line
	os.Args = []string{"--help"}

	var args struct {
		Input    string   `arg:"positional"`
		Output   []string `arg:"positional"`
		Verbose  bool     `arg:"-v,help:verbosity level"`
		Dataset  string   `arg:"help:dataset to use"`
		Optimize int      `arg:"-O,help:optimization level"`
	}
	arg.MustParse(&args)
}