Index: src/pkg/flag/flag.go |
=================================================================== |
--- 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 @@ |
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 @@ |
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 @@ |
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 @@ |
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 @@ |
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 @@ |
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 @@ |
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 @@ |
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) 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 @@ |
if !ok { |
return false |
} |
- ok = f.Value.set(value) |
+ ok = f.Value.Set(value) |
if !ok { |
return false |
} |
@@ -294,21 +298,10 @@ |
// 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 @@ |
// 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 @@ |
// 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 @@ |
// 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 @@ |
// 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 @@ |
// 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 @@ |
// 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 @@ |
// 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 @@ |
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 @@ |
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 @@ |
} |
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 @@ |
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() |