1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43

package main

import (
	"flag"
	"os"
	"time"

	"go.jolheiser.com/ffnix"
)

//go:generate go run main.go
func main() {
	fs := flag.NewFlagSet("myapp", flag.ExitOnError)
	fs.String("string-flag", "", "String flag with no default")
	fs.String("string-flag-default", "string default", "String flag with default")
	fs.Int("int-flag", 0, "Int flag with no default")
	fs.Int("int-flag-default", 100, "Int flag with default")
	fs.Bool("bool-flag-f", false, "Bool flag false")
	fs.Bool("bool-flag-t", true, "Bool flag true")
	fs.Duration("duration-flag", 0, "Duration flag with no default")
	fs.Duration("duration-flag-default", time.Minute*5, "Duration flag with default")

	os.MkdirAll("nix", os.ModePerm)
	results, err := ffnix.FlagSet(fs)
	if err != nil {
		panic(err)
	}

	write("nix/default.nix", results.Default)
	write("nix/module.nix", results.Module)
	write("nix/pkg.nix", results.Pkg)
}

func write(path, content string) {
	fi, err := os.Create(path)
	if err != nil {
		panic(err)
	}
	defer fi.Close()
	if _, err := fi.WriteString(content); err != nil {
		panic(err)
	}
}