package pflag

// -- func Value
type boolfuncValue func(string) error

func (f boolfuncValue) Set(s string) error { return f(s) }

func (f boolfuncValue) Type() string { return "boolfunc" }

func (f boolfuncValue) String() string { return "" } // same behavior as stdlib 'flag' package

func (f boolfuncValue) IsBoolFlag() bool { return true }

// BoolFunc defines a func flag with specified name, callback function and usage string.
//
// The callback function will be called every time "--{name}" (or any form that matches the flag) is parsed
// on the command line.
func (f *FlagSet) BoolFunc(name string, usage string, fn func(string) error) {
	f.BoolFuncP(name, "", usage, fn)
}

// BoolFuncP is like BoolFunc, but accepts a shorthand letter that can be used after a single dash.
func (f *FlagSet) BoolFuncP(name, shorthand string, usage string, fn func(string) error) {
	var val Value = boolfuncValue(fn)
	flag := f.VarPF(val, name, shorthand, usage)
	flag.NoOptDefVal = "true"
}

// BoolFunc defines a func flag with specified name, callback function and usage string.
//
// The callback function will be called every time "--{name}" (or any form that matches the flag) is parsed
// on the command line.
func BoolFunc(name string, usage string, fn func(string) error) {
	CommandLine.BoolFuncP(name, "", usage, fn)
}

// BoolFuncP is like BoolFunc, but accepts a shorthand letter that can be used after a single dash.
func BoolFuncP(name, shorthand string, usage string, fn func(string) error) {
	CommandLine.BoolFuncP(name, shorthand, usage, fn)
}