pars repres separ enumer liter param enumer enumer liter belong param liter liter edit happen param text pars pars except invalid input right messag shown user pars enumer liter fig object enumer object liter text pars except enumer liter project project project manag manag current project pars except pex start end notat util uml index check semicolon text start end text remov liter project trash liter text substr start end trim length non white char text remov liter project trash liter pars enumer liter liter model facad enumer liter enumer index liter check liter separ start end end notat util uml index check semicolon text start end start end text length text substr start end trim length ye object liter model core factori creat enumer liter liter model core helper add liter enumer liter model core helper add liter enumer liter pars enumer liter liter pars except ex pex pex ex start end end notat util uml index check semicolon text start pex pex 