add usage message

R=gri
OCL=13423
CL=13423

diff --git a/src/lib/flag.go b/src/lib/flag.go
index dc4863d9878c2630af40d4ae986d4c0551545c48..a0a1169ca3639a5840af1670e6d2831f0c3d1ebe 100644 (file)
--- a/src/lib/flag.go
+++ b/src/lib/flag.go
@@ -36,6 +36,8 @@ package flag
  *     Integer flags accept 1234, 0664, 0x1234 and may be negative.
  *     Boolean flags may be 1, 0, t, f, true, false, TRUE, FALSE, True, False.
  */
+ 
+import fmt "fmt"
 
 export Bool, Int, String
 export Arg, NArg
@@ -138,6 +140,15 @@ func (b *BoolValue) Set(val bool) {
        b.val = val
 }
 
+func (b *BoolValue) Str() string {
+       if b.val {
+               return "true"
+       }
+       else {
+               return "false"
+       }
+}
+
 func NewBoolValue(b bool, p *bool) *BoolValue {
        v := new(BoolValue);
        v.val = b;
@@ -187,6 +198,10 @@ func (i *IntValue) Set(val int64) {
        i.val = val
 }
 
+func (i *IntValue) Str() string {
+       return fmt.New().D(i.val).str()
+}
+
 func
 NewIntValue(i int64, p *int64) *IntValue {
        v := new(IntValue);
@@ -236,6 +251,10 @@ func (s *StringValue) Set(val string) {
        s.val = val
 }
 
+func (s *StringValue) Str() string {
+       return `"` + s.val + `"`
+}
+
 func NewStringValue(s string, p *string) *StringValue {
        v := new(StringValue);
        v.val = s;
@@ -251,6 +270,7 @@ type Value interface {
        IsBool()        bool;
        IsInt() bool;
        IsString()      bool;
+       Str()           string;
        ValidValue(str string) bool;
 }
 
@@ -259,12 +279,23 @@ type Flag struct {
        name    string;
        usage   string;
        value   Value;
+       next    *Flag;  // BUG: remove when we can iterate over maps
 }
 
 type Flags struct {
        actual *map[string] *Flag;
        formal *map[string] *Flag;
        first_arg       int;
+       flag_list       *Flag;  // BUG: remove when we can iterate over maps
+}
+
+func (flags *Flags) Usage() {
+       // BUG: use map iteration when available
+       print "Usage: \n";
+       for f := flags.flag_list; f != nil; f = f.next {
+               print "  -", f.name, "=", f.value.Str(), ": ", f.usage, "\n";
+       }
+       sys.exit(1);
 }
 
 // --Customer's value getters
@@ -322,6 +353,8 @@ func Add(name string, value Value, usage string) *Flag {
                panic "flag redefinition"
        }
        flags.formal[name] = f;
+       f.next = flags.flag_list;  // BUG: remove when we can iterate over maps
+       flags.flag_list = f;  // BUG: remove when we can iterate over maps
        return f;
 }
 
@@ -359,8 +392,8 @@ func (f *Flags) ParseOne(index int) (ok bool, next int)
        }
        name := s[num_minuses : len(s)];
        if len(name) == 0 || name[0] == '-' || name[0]=='=' {
-               print "bad flag syntax: ", s, "\n"
-               return false, -1
+               print "bad flag syntax: ", s, "\n";
+               f.Usage();
        }
 
        // it's a flag. does it have an argument?
@@ -376,14 +409,14 @@ func (f *Flags) ParseOne(index int) (ok bool, next int)
        }
        flag, alreadythere := flags.actual[name];
        if alreadythere {
-               print "flag specified twice: -", name, "\n"
-               return false, -1
+               print "flag specified twice: -", name, "\n";
+               f.Usage();
        }
        m := flags.formal;
        flag, alreadythere = m[name]; // BUG
        if !alreadythere {
-               print "flag provided but not defined: -", name, "\n"
-               return false, -1
+               print "flag provided but not defined: -", name, "\n";
+               f.Usage();
        }
        if !has_value && index < sys.argc()-1 && flag.value.ValidValue(sys.argv(index+1)) {
                // value is the next arg
@@ -396,8 +429,8 @@ func (f *Flags) ParseOne(index int) (ok bool, next int)
                        if has_value {
                                k, ok := atob(value);
                                if !ok {
-                                       print "invalid boolean value ", value, " for flag: -", name, "\n"
-                                       return false, -1
+                                       print "invalid boolean value ", value, " for flag: -", name, "\n";
+                                       f.Usage();
                                }
                                flag.value.AsBool().Set(k)
                        } else {
@@ -405,19 +438,19 @@ func (f *Flags) ParseOne(index int) (ok bool, next int)
                        }
                case flag.value.IsInt():
                        if !has_value {
-                               print "flag needs an argument: -", name, "\n"
-                               return false, -1
+                               print "flag needs an argument: -", name, "\n";
+                               f.Usage();
                        }
                        k, ok := atoi(value);
                        if !ok {
-                               print "invalid integer value ", value, " for flag: -", name, "\n"
-                               return false, -1
+                               print "invalid integer value ", value, " for flag: -", name, "\n";
+                               f.Usage();
                        }
                        flag.value.AsInt().Set(k)
                case flag.value.IsString():
                        if !has_value {
-                               print "flag needs an argument: -", name, "\n"
-                               return false, -1
+                               print "flag needs an argument: -", name, "\n";
+                               f.Usage();
                        }
                        flag.value.AsString().Set(value)
        }