diff --git a/README.md b/README.md index 3b62344..9e1d6cc 100644 --- a/README.md +++ b/README.md @@ -620,8 +620,8 @@ also supports dynamically adding commands via `kong.DynamicCommand()`. ## Variable interpolation -Kong supports limited variable interpolation into help strings, enum lists and -default values. +Kong supports limited variable interpolation into help strings, placeholder strings, +enum lists and default values. Variables are in the form: diff --git a/kong.go b/kong.go index 4f6be87..a09b711 100644 --- a/kong.go +++ b/kong.go @@ -270,6 +270,11 @@ func (k *Kong) interpolateValue(value *Value, vars Vars) (err error) { if len(value.Flag.Envs) != 0 { updatedVars["env"] = value.Flag.Envs[0] } + + value.Flag.PlaceHolder, err = interpolate(value.Flag.PlaceHolder, vars, updatedVars) + if err != nil { + return fmt.Errorf("placeholder value for %s: %s", value.Summary(), err) + } } value.Help, err = interpolate(value.Help, vars, updatedVars) if err != nil { diff --git a/kong_test.go b/kong_test.go index 4edda4f..3ea6b5f 100644 --- a/kong_test.go +++ b/kong_test.go @@ -766,8 +766,8 @@ func TestPassesThroughOriginalCommandError(t *testing.T) { func TestInterpolationIntoModel(t *testing.T) { var cli struct { - Flag string `default:"${default_value}" help:"Help, I need ${somebody}" enum:"${enum}"` - EnumRef string `enum:"a,b" required:"" help:"One of ${enum}"` + Flag string `default:"${default_value}" help:"Help, I need ${somebody}" enum:"${enum}" placeholder:"${enum}"` + EnumRef string `enum:"a,b" required:"" help:"One of ${enum}" placeholder:"${enum}"` EnvRef string `env:"${env}" help:"God ${env}"` } _, err := kong.New(&cli) @@ -787,7 +787,9 @@ func TestInterpolationIntoModel(t *testing.T) { assert.Equal(t, "Help, I need chickens!", flag.Help) assert.Equal(t, map[string]bool{"a": true, "b": true, "c": true, "d": true}, flag.EnumMap()) assert.Equal(t, []string{"a", "b", "c", "d"}, flag.EnumSlice()) + assert.Equal(t, "a,b,c,d", flag.PlaceHolder) assert.Equal(t, "One of a,b", flag2.Help) + assert.Equal(t, "a,b", flag2.PlaceHolder) assert.Equal(t, []string{"SAVE_THE_QUEEN"}, flag3.Envs) assert.Equal(t, "God SAVE_THE_QUEEN", flag3.Help) }