clean up flags package a bit.

fix a bug in Usage message - would print current value instead of default.

R=rsc
DELTA=53  (7 added, 4 deleted, 42 changed)
OCL=24323
CL=24323

diff --git a/src/lib/flag.go b/src/lib/flag.go
index 94bbbb49e525f1c8f8847672bc30b10faff66ca7..19d3e2ebfb1145bbbf67527c4ecdc5320afcaaad 100644 (file)
--- a/src/lib/flag.go
+++ b/src/lib/flag.go
@@ -14,8 +14,9 @@ package flag
  *     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")
+ *                     flag.IntVar(&flagvar, "flagname", 1234, "help message for flagname")
  *             }
+ *
  *     2) After all flags are defined, call
  *             flag.Parse()
  *     to parse the command line into the defined flags.
@@ -219,9 +220,10 @@ type _Value interface {
 
 // -- Flag structure (internal)
 type Flag struct {
-       name    string;
-       usage   string;
-       value   _Value;
+       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 {
@@ -234,7 +236,7 @@ var flags *allFlags = &allFlags{make(map[string] *Flag), make(map[string] *Flag)
 
 func PrintDefaults() {
        for k, f := range flags.formal {
-               print("  -", f.name, "=", f.value.str(), ": ", f.usage, "\n");
+               print("  -", f.name, "=", f.defvalue, ": ", f.usage, "\n");
        }
 }
 
@@ -269,75 +271,76 @@ func add(name string, value _Value, usage string) {
        f.name = name;
        f.usage = usage;
        f.value = value;
+       f.defvalue = value.str();       // Remember the default value as a string; it won't change.
        dummy, alreadythere := flags.formal[name];
        if alreadythere {
                print("flag redefined: ", name, "\n");
-               panic("flag redefinition");
+               panic("flag redefinition");     // Happens only if flags are declared with identical names
        }
        flags.formal[name] = f;
 }
 
+func BoolVar(p *bool, name string, value bool, usage string) {
+       add(name, newBoolValue(value, p), usage);
+}
+
 func Bool(name string, value bool, usage string) *bool {
        p := new(bool);
-       add(name, newBoolValue(value, p), usage);
+       BoolVar(p, name, value, usage);
        return p;
 }
 
-func BoolVar(p *bool, name string, value bool, usage string) {
-       add(name, newBoolValue(value, p), usage);
+func IntVar(p *int, name string, value int, usage string) {
+       add(name, newIntValue(value, p), usage);
 }
 
 func Int(name string, value int, usage string) *int {
        p := new(int);
-       add(name, newIntValue(value, p), usage);
+       IntVar(p, name, value, usage);
        return p;
 }
 
-func IntVar(p *int, name string, value int, usage string) {
-       add(name, newIntValue(value, p), usage);
+func Int64Var(p *int64, name string, value int64, usage string) {
+       add(name, newInt64Value(value, p), usage);
 }
 
 func Int64(name string, value int64, usage string) *int64 {
        p := new(int64);
-       add(name, newInt64Value(value, p), usage);
+       Int64Var(p, name, value, usage);
        return p;
 }
 
-func Int64Var(p *int64, name string, value int64, usage string) {
-       add(name, newInt64Value(value, p), usage);
+func UintVar(p *uint, name string, value uint, usage string) {
+       add(name, newUintValue(value, p), usage);
 }
 
 func Uint(name string, value uint, usage string) *uint {
        p := new(uint);
-       add(name, newUintValue(value, p), usage);
+       UintVar(p, name, value, usage);
        return p;
 }
 
-func UintVar(p *uint, name string, value uint, usage string) {
-       add(name, newUintValue(value, p), usage);
+func Uint64Var(p *uint64, name string, value uint64, usage string) {
+       add(name, newUint64Value(value, p), usage);
 }
 
 func Uint64(name string, value uint64, usage string) *uint64 {
        p := new(uint64);
-       add(name, newUint64Value(value, p), usage);
+       Uint64Var(p, name, value, usage);
        return p;
 }
 
-func Uint64Var(p *uint64, name string, value uint64, usage string) {
-       add(name, newUint64Value(value, p), usage);
+func StringVar(p *string, name, value string, usage string) {
+       add(name, newStringValue(value, p), usage);
 }
 
 func String(name, value string, usage string) *string {
        p := new(string);
-       add(name, newStringValue(value, p), usage);
+       StringVar(p, name, value, usage);
        return p;
 }
 
-func StringVar(p *string, name, value string, usage string) {
-       add(name, newStringValue(value, p), usage);
-}
-
-func (f *allFlags) ParseOne(index int) (ok bool, next int)
+func (f *allFlags) parseOne(index int) (ok bool, next int)
 {
        s := sys.Args[index];
        f.first_arg = index;  // until proven otherwise
@@ -434,7 +437,7 @@ func (f *allFlags) ParseOne(index int) (ok bool, next int)
 
 func Parse() {
        for i := 1; i < len(sys.Args); {
-               ok, next := flags.ParseOne(i);
+               ok, next := flags.parseOne(i);
                if next > 0 {
                        flags.first_arg = next;
                        i = next;