Tizen Developers

How to write script  logic in the program block in .edc file ?​    I find a script block ,we can use

   program { name: "shown,panel,click";
            signal: "mouse,clicked,*";
            source: "message.img.emotion";
            script {
               new st[31];
               new Float:vt;
               get_state(PART:"message.pannel",st,30,vl);
               if(!strcmp(st,"default")
                emit("message,panel,state,shown,0", "");
               else
                emit("message,panel,state,hidden,0","");
               }
         }

where can I get the tutorial about how to write a scrpit  ? such as the get_state function info .

thanks