WeintroducetheComputationandControlLanguage(CCL),aguarded-commandlanguageforexpressingsystemswhereincontrolandcomputationareinter-twined.ACCLprogramconsistsofasetofguardedcommandsthatmayupdatecontinuousordiscretevari-ablesandthatcanbereasonedaboutusingasimpletemporallogic.Inthispap