Improved documentation

flag.go

@@ -4,8 +4,12 @@ import "fmt"
 import "flag"
 import "strconv"
 
+// Flag is a common interface related to parsing flags in cli.
+// For more advanced flag parsing techniques, it is recomended that
+// this interface be implemented.
 type Flag interface {
 	fmt.Stringer
+	// Apply Flag settings to the given flag set
 	Apply(*flag.FlagSet)
 }