diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/pkg/flag/flag.go | 90 | ||||
| -rw-r--r-- | src/pkg/flag/flag_test.go | 19 |
2 files changed, 64 insertions, 45 deletions
diff --git a/src/pkg/flag/flag.go b/src/pkg/flag/flag.go index e51bf7ddc..0c2589c9e 100644 --- a/src/pkg/flag/flag.go +++ b/src/pkg/flag/flag.go @@ -15,6 +15,10 @@ 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. 2) After all flags are defined, call flag.Parse() @@ -63,7 +67,7 @@ func newBoolValue(val bool, p *bool) *boolValue { return &boolValue{p} } -func (b *boolValue) set(s string) bool { +func (b *boolValue) Set(s string) bool { v, err := strconv.Atob(s) *b.p = v return err == nil @@ -81,7 +85,7 @@ func newIntValue(val int, p *int) *intValue { return &intValue{p} } -func (i *intValue) set(s string) bool { +func (i *intValue) Set(s string) bool { v, err := strconv.Atoi(s) *i.p = int(v) return err == nil @@ -99,7 +103,7 @@ func newInt64Value(val int64, p *int64) *int64Value { return &int64Value{p} } -func (i *int64Value) set(s string) bool { +func (i *int64Value) Set(s string) bool { v, err := strconv.Atoi64(s) *i.p = v return err == nil @@ -117,7 +121,7 @@ func newUintValue(val uint, p *uint) *uintValue { return &uintValue{p} } -func (i *uintValue) set(s string) bool { +func (i *uintValue) Set(s string) bool { v, err := strconv.Atoui(s) *i.p = uint(v) return err == nil @@ -135,7 +139,7 @@ func newUint64Value(val uint64, p *uint64) *uint64Value { return &uint64Value{p} } -func (i *uint64Value) set(s string) bool { +func (i *uint64Value) Set(s string) bool { v, err := strconv.Atoui64(s) *i.p = uint64(v) return err == nil @@ -153,7 +157,7 @@ func newStringValue(val string, p *string) *stringValue { return &stringValue{p} } -func (s *stringValue) set(val string) bool { +func (s *stringValue) Set(val string) bool { *s.p = val return true } @@ -170,7 +174,7 @@ func newFloatValue(val float, p *float) *floatValue { return &floatValue{p} } -func (f *floatValue) set(s string) bool { +func (f *floatValue) Set(s string) bool { v, err := strconv.Atof(s) *f.p = v return err == nil @@ -188,7 +192,7 @@ func newFloat64Value(val float64, p *float64) *float64Value { return &float64Value{p} } -func (f *float64Value) set(s string) bool { +func (f *float64Value) Set(s string) bool { v, err := strconv.Atof64(s) *f.p = v return err == nil @@ -196,19 +200,19 @@ func (f *float64Value) set(s string) bool { func (f *float64Value) String() string { return fmt.Sprintf("%v", *f.p) } -// FlagValue is the interface to the dynamic value stored in a flag. +// Value is the interface to the dynamic value stored in a flag. // (The default value is represented as a string.) -type FlagValue interface { +type Value interface { String() string - set(string) bool + Set(string) bool } // A Flag represents the state of a flag. type Flag struct { - Name string // name as it appears on command line - Usage string // help message - Value FlagValue // value as set - DefValue string // default value (as text); for usage message + Name string // name as it appears on command line + Usage string // help message + Value Value // value as set + DefValue string // default value (as text); for usage message } type allFlags struct { @@ -249,7 +253,7 @@ func Set(name, value string) bool { if !ok { return false } - ok = f.Value.set(value) + ok = f.Value.Set(value) if !ok { return false } @@ -294,21 +298,10 @@ func NArg() int { return len(os.Args) - flags.first_arg } // Args returns the non-flag command-line arguments. func Args() []string { return os.Args[flags.first_arg:] } -func add(name string, value FlagValue, usage string) { - // Remember the default value as a string; it won't change. - f := &Flag{name, usage, value, value.String()} - _, alreadythere := flags.formal[name] - if alreadythere { - fmt.Fprintln(os.Stderr, "flag redefined:", name) - panic("flag redefinition") // Happens only if flags are declared with identical names - } - flags.formal[name] = f -} - // BoolVar defines a bool flag with specified name, default value, and usage string. // The argument p points to a bool variable in which to store the value of the flag. func BoolVar(p *bool, name string, value bool, usage string) { - add(name, newBoolValue(value, p), usage) + Var(newBoolValue(value, p), name, usage) } // Bool defines a bool flag with specified name, default value, and usage string. @@ -322,7 +315,7 @@ func Bool(name string, value bool, usage string) *bool { // IntVar defines an int flag with specified name, default value, and usage string. // The argument p points to an int variable in which to store the value of the flag. func IntVar(p *int, name string, value int, usage string) { - add(name, newIntValue(value, p), usage) + Var(newIntValue(value, p), name, usage) } // Int defines an int flag with specified name, default value, and usage string. @@ -336,7 +329,7 @@ func Int(name string, value int, usage string) *int { // Int64Var defines an int64 flag with specified name, default value, and usage string. // The argument p points to an int64 variable in which to store the value of the flag. func Int64Var(p *int64, name string, value int64, usage string) { - add(name, newInt64Value(value, p), usage) + Var(newInt64Value(value, p), name, usage) } // Int64 defines an int64 flag with specified name, default value, and usage string. @@ -350,7 +343,7 @@ func Int64(name string, value int64, usage string) *int64 { // UintVar defines a uint flag with specified name, default value, and usage string. // The argument p points to a uint variable in which to store the value of the flag. func UintVar(p *uint, name string, value uint, usage string) { - add(name, newUintValue(value, p), usage) + Var(newUintValue(value, p), name, usage) } // Uint defines a uint flag with specified name, default value, and usage string. @@ -364,7 +357,7 @@ func Uint(name string, value uint, usage string) *uint { // Uint64Var defines a uint64 flag with specified name, default value, and usage string. // The argument p points to a uint64 variable in which to store the value of the flag. func Uint64Var(p *uint64, name string, value uint64, usage string) { - add(name, newUint64Value(value, p), usage) + Var(newUint64Value(value, p), name, usage) } // Uint64 defines a uint64 flag with specified name, default value, and usage string. @@ -378,7 +371,7 @@ func Uint64(name string, value uint64, usage string) *uint64 { // StringVar defines a string flag with specified name, default value, and usage string. // The argument p points to a string variable in which to store the value of the flag. func StringVar(p *string, name, value string, usage string) { - add(name, newStringValue(value, p), usage) + Var(newStringValue(value, p), name, usage) } // String defines a string flag with specified name, default value, and usage string. @@ -392,7 +385,7 @@ func String(name, value string, usage string) *string { // FloatVar defines a float flag with specified name, default value, and usage string. // The argument p points to a float variable in which to store the value of the flag. func FloatVar(p *float, name string, value float, usage string) { - add(name, newFloatValue(value, p), usage) + Var(newFloatValue(value, p), name, usage) } // Float defines a float flag with specified name, default value, and usage string. @@ -406,7 +399,7 @@ func Float(name string, value float, usage string) *float { // Float64Var defines a float64 flag with specified name, default value, and usage string. // The argument p points to a float64 variable in which to store the value of the flag. func Float64Var(p *float64, name string, value float64, usage string) { - add(name, newFloat64Value(value, p), usage) + Var(newFloat64Value(value, p), name, usage) } // Float64 defines a float64 flag with specified name, default value, and usage string. @@ -417,6 +410,19 @@ func Float64(name string, value float64, usage string) *float64 { return p } +// Var defines a user-typed flag with specified name, default value, and usage string. +// The argument p points to a Value variable in which to store the value of the flag. +func Var(value Value, name string, usage string) { + // Remember the default value as a string; it won't change. + f := &Flag{name, usage, value, value.String()} + _, alreadythere := flags.formal[name] + if alreadythere { + fmt.Fprintln(os.Stderr, "flag redefined:", name) + panic("flag redefinition") // Happens only if flags are declared with identical names + } + flags.formal[name] = f +} + func (f *allFlags) parseOne(index int) (ok bool, next int) { s := os.Args[index] @@ -455,14 +461,8 @@ func (f *allFlags) parseOne(index int) (ok bool, next int) { break } } - flag, alreadythere := flags.actual[name] - if alreadythere { - fmt.Fprintf(os.Stderr, "flag specified twice: -%s\n", name) - Usage() - os.Exit(2) - } m := flags.formal - flag, alreadythere = m[name] // BUG + flag, alreadythere := m[name] // BUG if !alreadythere { fmt.Fprintf(os.Stderr, "flag provided but not defined: -%s\n", name) Usage() @@ -470,13 +470,13 @@ func (f *allFlags) parseOne(index int) (ok bool, next int) { } if f, ok := flag.Value.(*boolValue); ok { // special case: doesn't need an arg if has_value { - if !f.set(value) { + if !f.Set(value) { fmt.Fprintf(os.Stderr, "invalid boolean value %t for flag: -%s\n", value, name) Usage() os.Exit(2) } } else { - f.set("true") + f.Set("true") } } else { // It must have a value, which might be the next argument. @@ -491,7 +491,7 @@ func (f *allFlags) parseOne(index int) (ok bool, next int) { Usage() os.Exit(2) } - ok = flag.Value.set(value) + ok = flag.Value.Set(value) if !ok { fmt.Fprintf(os.Stderr, "invalid value %s for flag: -%s\n", value, name) Usage() diff --git a/src/pkg/flag/flag_test.go b/src/pkg/flag/flag_test.go index d6e642b2b..03e8a3e22 100644 --- a/src/pkg/flag/flag_test.go +++ b/src/pkg/flag/flag_test.go @@ -78,3 +78,22 @@ func TestEverything(t *testing.T) { } } } + +// Declare a user-defined flag. +// TODO: do the work to make this test better by resetting flag state +// and manipulating os.Args. +type flagVar []string + +func (f *flagVar) String() string { + return "foo" +} + +func (f *flagVar) Set(value string) bool { + return true +} + +var v flagVar + +func init() { + Var(&v, "testV", "usage") +} |