modify readme

Author: jindongh

README.md

@@ -2,3 +2,77 @@ obj-cli
 =======
 
 Object Oriented Command Line Interface Library of C++
+
+Introduce
+--------
+This is 
+
+Usage
+--------
+First, define a Request struct, include all possible parameters
+Second, define a Context class, include the 
+Thirdly, define the class and actions of the cli
+Finally, call cli_invoke to parse request and execute actions.
+
+Here are some example:
+
+### Simple
+        #include <obj-cli.h>
+        struct Request{
+                CLI_DECLARE(param1);
+                CLI_DECLARE(param2);
+        }
+        struct Context{
+                const char *password;
+        }
+        int func_dummy1(Request &, Context *){
+                return 0;
+        }
+        int func_dummy1(Request &, Context *){
+                return 0;
+        }
+        CliObject<Request,Context> meta[] = {
+                {
+                        "class1", {
+                                {
+                                        "action1",
+                                        func_dummy,
+                                        {
+                                        }
+                                },
+                                        "action2",
+                                        func_dummy2,
+                                        {
+                                        }
+                                }
+                        }
+                }, {
+                        "class2",{
+                        }
+                }
+        };
+        // ./a.out class1 action1 --param1=a --param2=b
+        // ./a.out class1 action2 --param2=a
+        int main(int argc, const char *argv[]) {
+                return cli_invoke<Request, Context>(argc, argv, meta, 3);
+        }
+### Advanced
+        int main(int argc, const char* argv[]) {
+                Request request;
+                Context context;
+                InvokeContext<Request, Context> env(argv[0], g_meta, meta_num, g_opt, opt_num);
+                int ret = cli_parse(argc, argv, request, env);
+                if(0 != ret){
+                        return ret;
+                }
+                if(0 != strcmp(request.password, "secret")){
+                        return -1;
+                }
+                context.password = "holy pot";
+                return cli_invoke(request, context, env);
+        }
+
+About
+--------
+For more information, please refer to the code
+For more and more information, please contact me via email which hides in codes.