submit

ass1.ml

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+(* name:WONG Yuk Chun , itsc:ycwongal , sid :20419764 *)
+
+Control.Print.printDepth := 100;
+
+datatype course = C of (string * string) list;
+datatype enroll = E of (int * string list) list;
+
+(*Helper functions*)
+fun reduce f [ ] v = v
+|   reduce f (head::tail) v = f (head, reduce f tail v);
+
+fun AppendUnique ([],L2,f) = L2
+|   AppendUnique (L1h::L1t , L2,f) = 
+        let
+            fun Exist_ (el,[]) = false
+            |   Exist_ (el, h::t) = if(f el h) then true else Exist_ (el, t);
+        in
+            if(Exist_ (L1h , L2)) then AppendUnique (L1t , L2, f) else AppendUnique (L1t , L2 @ [L1h],f)
+        end;
+
+(*Q1*)
+fun CourseMatch (a:(string * string)) (b:(string * string)) = #1a= #1b;
+
+fun insert_course ([],c:course) = c
+|   insert_course(h::t,C([])) = C(h::t)
+|   insert_course(l,C(L)) = C(AppendUnique (l,L,CourseMatch));
+
+(*Q2*)
+fun StrMatch (a:string) (b:string) = a=b;
+
+fun insert_enroll (s:(int * string list),E([])) = E([s])
+|   insert_enroll (s,E(L)) = 
+        let 
+            fun Exist(s:(int * string list),E([])) = false
+            |   Exist(s,E(h::t)) = 
+                if( #1s= #1h) then true
+                else Exist(s,E(t));    
+        in 
+            if(Exist(s,E(L))) then E(map (
+                    fn x=> 
+                        if(#1s= #1x) 
+                        then (#1x, AppendUnique( #2s , #2x, StrMatch)) 
+                        else x
+                    ) L
+                ) else E(L@[s]) end;
+
+(*Q3*)
+fun query_students (course_id,E(L)) =
+    let 
+        fun Exist__ (course_id, []) = false
+        |   Exist__ (course_id, h::t) = if (course_id = h) then true else Exist__ (course_id, t);
+
+        fun push_students (course_id,E([]),[]) = []
+        |   push_students (course_id,E([]),students) = students
+        |   push_students (course_id,E(h::t),students) = 
+                if( Exist__ (course_id, #2 h)) then push_students (course_id,E(t),students @ [#1 h])
+                else push_students (course_id,E(t),students);
+    in
+        push_students(course_id,E(L),[])
+    end;
+
+(*Q4*)
+fun IntMatch a b = a=b;
+fun list_distinct_students (prof, C(c), E(e)) =
+    let fun Helper (prof, C([]), E(_), students_list) = students_list
+    |   Helper (prof, C(_), E([]), students_list) = students_list 
+    |   Helper (prof, C(h::t), E(e), students_list) = 
+        if ( #2 h = prof) then Helper (prof, C(t), E(e), AppendUnique(query_students(#1 h, E(e)), students_list, IntMatch))
+        else Helper (prof, C(t), E(e), students_list)
+    in Helper (prof, C(c), E(e), []) end;
+
+fun count_distinct_students (prof, C(c), E(e)) = length(list_distinct_students (prof, C(c), E(e))) ;
+
+(*Q5*)
+(*remove course and enrollment by course id*)
+fun delete_course_enroll (course_id, C(c), E(e)) = 
+    let fun delete_course (course_id, C([]), C(c_list)) = C(c_list)
+        |   delete_course (course_id, C(h::t), C(c_list)) = 
+            if (course_id = #1 h) then delete_course (course_id, C(t), C(c_list))
+            else delete_course (course_id, C(t), C(c_list@[h]));
+        fun delete_enroll (course_id, E([]) , E(e_list)) = E(e_list)
+        |   delete_enroll (course_id , E(h::t), E(e_list)) = 
+            let fun student_drop (course_id, [], fin_courses) = fin_courses
+                |   student_drop (course_id, h::t, fin_courses) = 
+                    if(h = course_id) then student_drop (course_id , t, fin_courses)
+                    else student_drop (course_id , t, fin_courses@[h]);
+                val std = (# 1 h , student_drop (course_id, #2 h, []))
+            in
+
+            delete_enroll (course_id, E(t), E(e_list@[std])) end;
+    in
+
+    (delete_course(course_id,C(c),C([])) , delete_enroll(course_id,E(e),E([])))
+
+end;

assignment_1_test_cases.ml

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+print("....(Q1)....");
+insert_course ([], C [("comp10", "p01")]);
+insert_course ([("comp12", "p02")], C []);
+insert_course ([("comp10", "p02")], C [("comp10", "p01")]);
+insert_course ([("comp13", "p01"), ("comp12", "p02")], C [("comp10","p01")]);
+
+print("....(Q2)....");
+ insert_enroll ((1702, []), E [(1701, ["comp10", "comp11"])]);
+ insert_enroll ((1701, ["comp10", "comp11"]), E []);
+ insert_enroll ((1701, ["comp11", "comp10"]), E [(1701, ["comp10",
+"comp12"])]);
+insert_enroll ((1702, ["comp10"]), E [(1701, ["comp10", "comp11"])]);
+
+print("....(Q3)....");
+query_students ("comp10", E []);
+query_students ("comp10", E [(1701, ["comp10"])]);
+query_students ("comp11", E [(1701, ["comp10"])]);
+query_students ("comp10", E [(1701, ["comp10", "comp11"]), (1702,
+["comp13", "comp10"]), (1703, [])]);
+
+print("....(Q4)....");
+count_distinct_students ("p01", C [], E []);
+count_distinct_students ("p01", C [("comp10", "p01")], E []);
+count_distinct_students ("p01", C [("comp10", "p01")], E [(1701,
+["comp10"]), (1702, ["comp13"])]);
+count_distinct_students ("p01", C [("comp10", "p01"), ("comp12",
+"p02"), ("comp13", "p01")], E [(1701, ["comp10", "comp11"]), (1702,
+["comp13"])]);
+
+print("....(Q5)....");
+delete_course_enroll ("comp10", C [], E[]);
+delete_course_enroll ("comp10", C [("comp10", "p01")], E []);
+delete_course_enroll ("comp10", C [("comp10", "p01")], E [(1701,
+["comp10"])]);
+delete_course_enroll ("comp10", C [("comp10", "p01"), ("comp12",
+"p02")], E [(1701, ["comp10", "comp11"]), (1702, ["comp13", "comp10"]),
+(1703, [])]);