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Add optional localization.
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@brendanburns
brendanburns committed Mar 13, 2017
1 parent 9ff6c69 commit e096bcc
Showing 1 changed file with 43 additions and 23 deletions.
66 changes: 43 additions & 23 deletions flag.go
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Original file line number Diff line number Diff line change
Expand Up @@ -146,6 +146,7 @@ type FlagSet struct {
output io.Writer // nil means stderr; use out() accessor
interspersed bool // allow interspersed option/non-option args
normalizeNameFunc func(f *FlagSet, name string) NormalizedName
localizeFunc func(str string) string
}

// A Flag represents the state of a flag.
Expand Down Expand Up @@ -187,6 +188,25 @@ func sortFlags(flags map[NormalizedName]*Flag) []*Flag {
return result
}

// Sets the localization function for this flag set.
// This function will be used to localize the 'usage' string for
// all flags added to this FlagSet. It is also applied to all existing
// flags in the flag set.
// Should probably only be set once.
func (f *FlagSet) SetLocalizeFunc(n func(str string) string) {
f.localizeFunc = n
for _, v := range f.formal {
v.Usage = f.localize(v.Usage)
}
}

func (f *FlagSet) localize(str string) string {
if f.localizeFunc != nil {
return f.localizeFunc(str)
}
return str
}

// SetNormalizeFunc allows you to add a function which can translate flag names.
// Flags added to the FlagSet will be translated and then when anything tries to
// look up the flag that will also be translated. So it would be possible to create
Expand Down Expand Up @@ -287,12 +307,12 @@ func (f *FlagSet) lookup(name NormalizedName) *Flag {
func (f *FlagSet) getFlagType(name string, ftype string, convFunc func(sval string) (interface{}, error)) (interface{}, error) {
flag := f.Lookup(name)
if flag == nil {
err := fmt.Errorf("flag accessed but not defined: %s", name)
err := fmt.Errorf(f.localize("flag accessed but not defined: %s"), name)
return nil, err
}

if flag.Value.Type() != ftype {
err := fmt.Errorf("trying to get %s value of flag of type %s", ftype, flag.Value.Type())
err := fmt.Errorf(f.localize("trying to get %s value of flag of type %s"), ftype, flag.Value.Type())
return nil, err
}

Expand All @@ -317,10 +337,10 @@ func (f *FlagSet) ArgsLenAtDash() int {
func (f *FlagSet) MarkDeprecated(name string, usageMessage string) error {
flag := f.Lookup(name)
if flag == nil {
return fmt.Errorf("flag %q does not exist", name)
return fmt.Errorf(f.localize("flag %q does not exist"), name)
}
if len(usageMessage) == 0 {
return fmt.Errorf("deprecated message for flag %q must be set", name)
return fmt.Errorf(f.localize("deprecated message for flag %q must be set"), name)
}
flag.Deprecated = usageMessage
return nil
Expand All @@ -332,10 +352,10 @@ func (f *FlagSet) MarkDeprecated(name string, usageMessage string) error {
func (f *FlagSet) MarkShorthandDeprecated(name string, usageMessage string) error {
flag := f.Lookup(name)
if flag == nil {
return fmt.Errorf("flag %q does not exist", name)
return fmt.Errorf(f.localize("flag %q does not exist"), name)
}
if len(usageMessage) == 0 {
return fmt.Errorf("deprecated message for flag %q must be set", name)
return fmt.Errorf(f.localize("deprecated message for flag %q must be set"), name)
}
flag.ShorthandDeprecated = usageMessage
return nil
Expand All @@ -346,7 +366,7 @@ func (f *FlagSet) MarkShorthandDeprecated(name string, usageMessage string) erro
func (f *FlagSet) MarkHidden(name string) error {
flag := f.Lookup(name)
if flag == nil {
return fmt.Errorf("flag %q does not exist", name)
return fmt.Errorf(f.localize("flag %q does not exist"), name)
}
flag.Hidden = true
return nil
Expand All @@ -363,7 +383,7 @@ func (f *FlagSet) Set(name, value string) error {
normalName := f.normalizeFlagName(name)
flag, ok := f.formal[normalName]
if !ok {
return fmt.Errorf("no such flag -%v", name)
return fmt.Errorf(f.localize("no such flag -%v"), name)
}
err := flag.Value.Set(value)
if err != nil {
Expand All @@ -375,7 +395,7 @@ func (f *FlagSet) Set(name, value string) error {
f.actual[normalName] = flag
flag.Changed = true
if len(flag.Deprecated) > 0 {
fmt.Fprintf(os.Stderr, "Flag --%s has been deprecated, %s\n", flag.Name, flag.Deprecated)
fmt.Fprintf(os.Stderr, f.localize("Flag --%s has been deprecated, %s\n"), flag.Name, flag.Deprecated)
}
return nil
}
Expand All @@ -387,7 +407,7 @@ func (f *FlagSet) SetAnnotation(name, key string, values []string) error {
normalName := f.normalizeFlagName(name)
flag, ok := f.formal[normalName]
if !ok {
return fmt.Errorf("no such flag -%v", name)
return fmt.Errorf(f.localize("no such flag -%v"), name)
}
if flag.Annotations == nil {
flag.Annotations = map[string][]string{}
Expand Down Expand Up @@ -633,7 +653,7 @@ func PrintDefaults() {

// defaultUsage is the default function to print a usage message.
func defaultUsage(f *FlagSet) {
fmt.Fprintf(f.out(), "Usage of %s:\n", f.name)
fmt.Fprintf(f.out(), f.localize("Usage of %s:\n"), f.name)
f.PrintDefaults()
}

Expand Down Expand Up @@ -699,7 +719,7 @@ func (f *FlagSet) VarPF(value Value, name, shorthand, usage string) *Flag {
flag := &Flag{
Name: name,
Shorthand: shorthand,
Usage: usage,
Usage: f.localize(usage),
Value: value,
DefValue: value.String(),
}
Expand All @@ -719,7 +739,7 @@ func (f *FlagSet) AddFlag(flag *Flag) {

_, alreadythere := f.formal[normalizedFlagName]
if alreadythere {
msg := fmt.Sprintf("%s flag redefined: %s", f.name, flag.Name)
msg := fmt.Sprintf(f.localize("%s flag redefined: %s"), f.name, flag.Name)
fmt.Fprintln(f.out(), msg)
panic(msg) // Happens only if flags are declared with identical names
}
Expand All @@ -734,7 +754,7 @@ func (f *FlagSet) AddFlag(flag *Flag) {
return
}
if len(flag.Shorthand) > 1 {
fmt.Fprintf(f.out(), "%s shorthand more than ASCII character: %s\n", f.name, flag.Shorthand)
fmt.Fprintf(f.out(), f.localize("%s shorthand more than ASCII character: %s\n"), f.name, flag.Shorthand)
panic("shorthand is more than one character")
}
if f.shorthands == nil {
Expand All @@ -743,7 +763,7 @@ func (f *FlagSet) AddFlag(flag *Flag) {
c := flag.Shorthand[0]
old, alreadythere := f.shorthands[c]
if alreadythere {
fmt.Fprintf(f.out(), "%s shorthand reused: %q for %s already used for %s\n", f.name, c, flag.Name, old.Name)
fmt.Fprintf(f.out(), f.localize("%s shorthand reused: %q for %s already used for %s\n"), f.name, c, flag.Name, old.Name)
panic("shorthand redefinition")
}
f.shorthands[c] = flag
Expand Down Expand Up @@ -800,7 +820,7 @@ func (f *FlagSet) usage() {

func (f *FlagSet) setFlag(flag *Flag, value string, origArg string) error {
if err := flag.Value.Set(value); err != nil {
return f.failf("invalid argument %q for %s: %v", value, origArg, err)
return f.failf(f.localize("invalid argument %q for %s: %v"), value, origArg, err)
}
// mark as visited for Visit()
if f.actual == nil {
Expand All @@ -809,10 +829,10 @@ func (f *FlagSet) setFlag(flag *Flag, value string, origArg string) error {
f.actual[f.normalizeFlagName(flag.Name)] = flag
flag.Changed = true
if len(flag.Deprecated) > 0 {
fmt.Fprintf(os.Stderr, "Flag --%s has been deprecated, %s\n", flag.Name, flag.Deprecated)
fmt.Fprintf(os.Stderr, f.localize("Flag --%s has been deprecated, %s\n"), flag.Name, flag.Deprecated)
}
if len(flag.ShorthandDeprecated) > 0 && containsShorthand(origArg, flag.Shorthand) {
fmt.Fprintf(os.Stderr, "Flag shorthand -%s has been deprecated, %s\n", flag.Shorthand, flag.ShorthandDeprecated)
fmt.Fprintf(os.Stderr, f.localize("Flag shorthand -%s has been deprecated, %s\n"), flag.Shorthand, flag.ShorthandDeprecated)
}
return nil
}
Expand All @@ -830,7 +850,7 @@ func (f *FlagSet) parseLongArg(s string, args []string, fn parseFunc) (a []strin
a = args
name := s[2:]
if len(name) == 0 || name[0] == '-' || name[0] == '=' {
err = f.failf("bad flag syntax: %s", s)
err = f.failf(f.localize("bad flag syntax: %s"), s)
return
}
split := strings.SplitN(name, "=", 2)
Expand All @@ -841,7 +861,7 @@ func (f *FlagSet) parseLongArg(s string, args []string, fn parseFunc) (a []strin
f.usage()
return a, ErrHelp
}
err = f.failf("unknown flag: --%s", name)
err = f.failf(f.localize("unknown flag: --%s"), name)
return
}
var value string
Expand All @@ -857,7 +877,7 @@ func (f *FlagSet) parseLongArg(s string, args []string, fn parseFunc) (a []strin
a = a[1:]
} else {
// '--flag' (arg was required)
err = f.failf("flag needs an argument: %s", s)
err = f.failf(f.localize("flag needs an argument: %s"), s)
return
}
err = fn(flag, value, s)
Expand All @@ -880,7 +900,7 @@ func (f *FlagSet) parseSingleShortArg(shorthands string, args []string, fn parse
return
}
//TODO continue on error
err = f.failf("unknown shorthand flag: %q in -%s", c, shorthands)
err = f.failf(f.localize("unknown shorthand flag: %q in -%s"), c, shorthands)
return
}
var value string
Expand All @@ -896,7 +916,7 @@ func (f *FlagSet) parseSingleShortArg(shorthands string, args []string, fn parse
value = args[0]
outArgs = args[1:]
} else {
err = f.failf("flag needs an argument: %q in -%s", c, shorthands)
err = f.failf(f.localize("flag needs an argument: %q in -%s"), c, shorthands)
return
}
err = fn(flag, value, shorthands)
Expand Down

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