handl effect action transit distinct case ul li effect given exist li express effect present alter li effect given exist li express effect present remov ul reaction case ul li creat action set languag express hook transit li chang effect express leav actiontyp languag untouch li nop li unhook eras exist effect ul param action pars param tran transit caus effect action pars effect object tran action object effect model facad effect tran action length effect effect model common behavior factori creat action hook transit immedi except caus remain dangl defin statediagram defin activitydiagram lp statediagram granular type statement lp activitydiagram granular type statement lp activitydiagram local nest statement lp statediagram local nest statement model state machin helper set effect tran effect endif model common behavior helper set script effect model data type factori creat action express languag action model core helper set effect anon object script model facad script effect languag script model data type helper languag script model common behavior helper set script effect model data type factori creat action express languag action effect delet effect eras 