1 files changed, 245 insertions, 0 deletions
diff --git a/compflag/compflag.go b/compflag/compflag.go
new file mode 100644
index 0000000..cfb4440
--- /dev/null
+++ b/compflag/compflag.go
@@ -0,0 +1,245 @@
+// Package compflag provides a handful of standard library-compatible flags with bash complition capabilities.
+//
+// Usage
+//
+// 	import "github.com/posener/complete/compflag"
+//
+// 	var (
+// 		// Define flags...
+// 		foo = compflag.String("foo", "", "")
+// 	)
+//
+// 	func main() {
+// 		compflag.Parse("my-program")
+// 		// Main function.
+// 	}
+//
+// Alternatively, the library can just be used with the standard library flag package:
+//
+// 	import (
+// 		"flag"
+// 		"github.com/posener/complete/compflag"
+// 	)
+//
+// 	var (
+// 		// Define flags...
+// 		foo = compflag.String("foo", "", "")
+// 		bar = flag.String("bar", "", "")
+// 	)
+//
+// 	func main() {
+// 		complete.CommandLine("my-program")
+// 		flag.ParseArgs()
+// 		// Main function.
+// 	}
+package compflag
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+
+	"github.com/posener/complete"
+)
+
+// Flag options.
+type Option func(*options)
+
+// OptValues allows to set a desired set of valid values for the flag.
+func OptValues(values ...string) Option {
+	return func(o *options) { o.values = values }
+}
+
+// OptCheck enforces the valid values on the predicted flag.
+func OptCheck() Option {
+	return func(o *options) { o.check = true }
+}
+
+type options struct {
+	values []string
+	check  bool
+}
+
+func config(fs ...Option) options {
+	var op options
+	for _, f := range fs {
+		f(&op)
+	}
+	return op
+}
+
+// FlagSet is bash completion enabled flag.FlagSet.
+type FlagSet flag.FlagSet
+
+// Parse parses command line arguments.
+func (fs *FlagSet) Parse(args []string) error {
+	return (*flag.FlagSet)(fs).Parse(args)
+}
+
+// Complete performs bash completion if needed.
+func (fs *FlagSet) Complete(name string) {
+	complete.Complete(name, complete.FlagSet((*flag.FlagSet)(CommandLine)))
+}
+
+func (fs *FlagSet) String(name string, value string, usage string, options ...Option) *string {
+	p := new(string)
+	(*flag.FlagSet)(fs).Var(newStringValue(value, p, config(options...)), name, usage)
+	return p
+}
+
+func (fs *FlagSet) Bool(name string, value bool, usage string, options ...Option) *bool {
+	p := new(bool)
+	(*flag.FlagSet)(fs).Var(newBoolValue(value, p, config(options...)), name, usage)
+	return p
+}
+
+func (fs *FlagSet) Int(name string, value int, usage string, options ...Option) *int {
+	p := new(int)
+	(*flag.FlagSet)(fs).Var(newIntValue(value, p, config(options...)), name, usage)
+	return p
+}
+
+func (o options) checkValue(v string) error {
+	if !o.check || len(o.values) == 0 {
+		return nil
+	}
+	for _, vv := range o.values {
+		if v == vv {
+			return nil
+		}
+	}
+	return fmt.Errorf("not in allowed values: %s", strings.Join(o.values, ","))
+}
+
+var CommandLine = (*FlagSet)(flag.CommandLine)
+
+// Parse parses command line arguments. It also performs bash completion when needed.
+func Parse(name string) {
+	CommandLine.Complete(name)
+	CommandLine.Parse(os.Args[1:])
+}
+
+func String(name string, value string, usage string, options ...Option) *string {
+	return CommandLine.String(name, value, usage, options...)
+}
+
+func Bool(name string, value bool, usage string, options ...Option) *bool {
+	return CommandLine.Bool(name, value, usage, options...)
+}
+
+func Int(name string, value int, usage string, options ...Option) *int {
+	return CommandLine.Int(name, value, usage, options...)
+}
+
+type boolValue struct {
+	v *bool
+	options
+}
+
+func newBoolValue(val bool, p *bool, o options) *boolValue {
+	*p = val
+	return &boolValue{v: p, options: o}
+}
+
+func (b *boolValue) Set(val string) error {
+	v, err := strconv.ParseBool(val)
+	*b.v = v
+	if err != nil {
+		return fmt.Errorf("bad value for bool flag")
+	}
+	return b.checkValue(val)
+}
+
+func (b *boolValue) Get() interface{} { return bool(*b.v) }
+
+func (b *boolValue) String() string {
+	if b == nil || b.v == nil {
+		return strconv.FormatBool(false)
+	}
+	return strconv.FormatBool(bool(*b.v))
+}
+
+func (b *boolValue) IsBoolFlag() bool { return true }
+
+func (b *boolValue) Predict(_ string) []string {
+	if b.values != nil {
+		return b.values
+	}
+	// If false, typing the bool flag is expected to turn it on, so there is nothing to complete
+	// after the flag.
+	if !*b.v {
+		return nil
+	}
+	// Otherwise, suggest only to turn it off.
+	return []string{"false"}
+}
+
+type stringValue struct {
+	v *string
+	options
+}
+
+func newStringValue(val string, p *string, o options) *stringValue {
+	*p = val
+	return &stringValue{v: p, options: o}
+}
+
+func (s *stringValue) Set(val string) error {
+	*s.v = val
+	return s.options.checkValue(val)
+}
+
+func (s *stringValue) Get() interface{} {
+	return string(*s.v)
+}
+
+func (s *stringValue) String() string {
+	if s == nil || s.v == nil {
+		return ""
+	}
+	return string(*s.v)
+}
+
+func (s *stringValue) Predict(_ string) []string {
+	if s.values != nil {
+		return s.values
+	}
+	return []string{""}
+}
+
+type intValue struct {
+	v *int
+	options
+}
+
+func newIntValue(val int, p *int, o options) *intValue {
+	*p = val
+	return &intValue{v: p, options: o}
+}
+
+func (i *intValue) Set(val string) error {
+	v, err := strconv.ParseInt(val, 0, strconv.IntSize)
+	*i.v = int(v)
+	if err != nil {
+		return fmt.Errorf("bad value for int flag")
+	}
+	return i.checkValue(val)
+}
+
+func (i *intValue) Get() interface{} { return int(*i.v) }
+
+func (i *intValue) String() string {
+	if i == nil || i.v == nil {
+		return strconv.Itoa(0)
+	}
+	return strconv.Itoa(int(*i.v))
+}
+
+func (s *intValue) Predict(_ string) []string {
+	if s.values != nil {
+		return s.values
+	}
+	return []string{""}
+}