https://sourceforge.net/p/alloymda/wiki/Student.als/Recent changes to Student.alsenTue, 20 Mar 2012 18:09:14 -0000https://sourceforge.net/p/alloymda/wiki/Student.als/~~~~~~ module Student sig Time {} sig Name {} fact { all n : Name | lone name.n } sig Course { labs : some Lab } sig Lab {} fact { all l : Lab | lone labs.l } enum Grade { A,B,C,D,E } sig Student { name : one Name, approved : Course -> Time, current : Course lone -> Time, donelabs : Lab -> Time, exams : Course -> Grade lone -> Time } fact { all t : Time | all s : Student | s.current.t not in s.approved.t } fact { all t : Time | all s : Student | all c : s.approved.t | c.labs in s.donelabs.t and c.(s.exams.t) in A+B+C+D } fact { all t : Time | all s : Student | (s.current.t + s.approved.t + (s.exams.t).Grade) in ((students.t).s).courses } sig College { students : Student -> Time, courses : set Course } fact { all t : Time | all s : Student | one (students.t).s } run {} for 4 but exactly 1 Student, exactly 1 Time pred newstudent [c : College, s : Student, t,t' : Time] { no (students.t).s no s.approved.t no s.current.t no s.donelabs.t no s.exams.t students.t' = students.t + c -> s } pred enroll [s : Student, c : Course, t,t' : Time] { no s.current.t c not in s.approved.t current.t' = current.t + s -> c } pred lab [s : Student, l : Lab, t,t' : Time] { some s.current.t l not in (s.donelabs.t) l in (s.current.t).labs donelabs.t' = donelabs.t + s -> l } pred exam [s : Student, g : Grade, t,t' : Time] { some s.current.t s.current.t not in (s.exams.t).Grade exams.t' = exams.t + s -> s.current.t -> g } pred approve [s : Student, t,t' : Time] { some s.current.t (s.current.t).(s.exams.t) in A+B+C+D (s.current.t).labs in s.donelabs.t approved.t' = approved.t + s -> s.current.t current.t' = current.t - s -> Course } pred quit [s : Student, t,t' : Time] { some s.current.t exams.t' = exams.t - s -> s.current.t -> Grade donelabs.t' = donelabs.t - s -> (s.current.t).labs current.t' = current.t - s -> Course } ~~~~~~Alcino CunhaTue, 20 Mar 2012 18:09:14 -0000https://sourceforge.net500b5ac5c205e29bc5e2d4b39b340272d647048a