diff --git a/flag.go b/flag.go index 7c058de3..71773a80 100644 --- a/flag.go +++ b/flag.go @@ -27,23 +27,32 @@ unaffected. Define flags using flag.String(), Bool(), Int(), etc. This declares an integer flag, -flagname, stored in the pointer ip, with type *int. + var ip = flag.Int("flagname", 1234, "help message for flagname") + If you like, you can bind the flag to a variable using the Var() functions. + var flagvar int func init() { flag.IntVar(&flagvar, "flagname", 1234, "help message for flagname") } + Or you can create custom flags that satisfy the Value interface (with pointer receivers) and couple them to flag parsing by + flag.Var(&flagVal, "name", "help message for flagname") + For such flags, the default value is just the initial value of the variable. After all flags are defined, call + flag.Parse() + to parse the command line into the defined flags. Flags may then be used directly. If you're using the flags themselves, they are all pointers; if you bind to variables, they're values. + fmt.Println("ip has value ", *ip) fmt.Println("flagvar has value ", flagvar) @@ -54,22 +63,26 @@ The arguments are indexed from 0 through flag.NArg()-1. The pflag package also defines some new functions that are not in flag, that give one-letter shorthands for flags. You can use these by appending 'P' to the name of any function that defines a flag. + var ip = flag.IntP("flagname", "f", 1234, "help message") var flagvar bool func init() { flag.BoolVarP(&flagvar, "boolname", "b", true, "help message") } flag.VarP(&flagval, "varname", "v", "help message") + Shorthand letters can be used with single dashes on the command line. Boolean shorthand flags can be combined with other shorthand flags. Command line flag syntax: + --flag // boolean flags only --flag=x Unlike the flag package, a single dash before an option means something different than a double dash. Single dashes signify a series of shorthand letters for flags. All but the last shorthand letter must be boolean flags. + // boolean flags -f -abc @@ -934,9 +947,9 @@ func (f *FlagSet) usage() { } } -//--unknown (args will be empty) -//--unknown --next-flag ... (args will be --next-flag ...) -//--unknown arg ... (args will be arg ...) +// --unknown (args will be empty) +// --unknown --next-flag ... (args will be --next-flag ...) +// --unknown arg ... (args will be arg ...) func stripUnknownFlagValue(args []string) []string { if len(args) == 0 { //--unknown @@ -1135,7 +1148,7 @@ func (f *FlagSet) Parse(arguments []string) error { } f.parsed = true - if len(arguments) < 0 { + if len(arguments) == 0 { return nil } diff --git a/flag_test.go b/flag_test.go index 58a5d25a..05026188 100644 --- a/flag_test.go +++ b/flag_test.go @@ -100,6 +100,12 @@ func TestEverything(t *testing.T) { } } +func TestNoArgument(t *testing.T) { + if GetCommandLine().Parse([]string{}) != nil { + t.Error("parse failed for empty argument list") + } +} + func TestUsage(t *testing.T) { called := false ResetForTesting(func() { called = true }) @@ -1134,7 +1140,6 @@ func TestMultipleNormalizeFlagNameInvocations(t *testing.T) { } } -// func TestHiddenFlagInUsage(t *testing.T) { f := NewFlagSet("bob", ContinueOnError) f.Bool("secretFlag", true, "shhh") @@ -1149,7 +1154,6 @@ func TestHiddenFlagInUsage(t *testing.T) { } } -// func TestHiddenFlagUsage(t *testing.T) { f := NewFlagSet("bob", ContinueOnError) f.Bool("secretFlag", true, "shhh")