restructure + lecutre 07

labs/04/records.ml

@@ -0,0 +1,160 @@
+(** [record] of a person with a first name, last name, and score *)
+type record = {firstname: string; lastname: string; score: int};;
+
+(** [print_records r] takes a list of records [r] and prints
+  * each record neatly to the console *)
+let rec print_records r =
+  match r with
+  | [] -> ()
+  | x :: xs -> Printf.printf "%3d %s %s\n" x.score x.lastname x.firstname; print_records xs;;
+
+(** [compare_records r1 r2] compares records [r1] and [r2] based
+  * on score, then by lastname, then by firstname.
+  *)
+let compare_records r1 r2 =
+  compare
+    (r2.score, r2.lastname, r2.firstname)
+    (r1.score, r1.lastname, r1.firstname);;
+
+(**/**)
+let test_compare_records () =
+  assert (compare_records
+    {firstname = "homer"; lastname = "simpson"; score = 10}
+    {firstname = "marge"; lastname = "simpson"; score = 25}
+   > 0);
+  assert (compare_records
+    {firstname = "bart"; lastname = "simpson"; score = 25}
+    {firstname = "marge"; lastname = "simpson"; score = 25}
+   > 0);
+  assert (compare_records
+    {firstname = "marge"; lastname = "simpson"; score = 25}
+    {firstname = "bart"; lastname = "simpson"; score = 25}
+  < 0);;
+(**/**)
+
+(** [records_insert x l] inserts a record element [x] into
+  * list of records [l]
+  * Requires: [l] is in ascending order. *)
+let rec records_insert x l =
+  match l with
+  | y :: ys when compare_records x y > 0 -> y :: records_insert x ys
+  | _ -> x :: l;;
+
+(**/**)
+let test_records_insert () =
+  assert (records_insert
+    {firstname = "a"; lastname = "b"; score = 1} [] =
+    [{firstname = "a"; lastname = "b"; score = 1}]
+  );
+  assert (records_insert
+    {firstname = "a"; lastname = "b"; score = 1}
+    [{firstname = "c"; lastname = "d"; score = 2}] =
+  [
+    {firstname = "c"; lastname = "d"; score = 2};
+    {firstname = "a"; lastname = "b"; score = 1}
+  ]);
+  assert (records_insert
+    {firstname = "e"; lastname = "f"; score = 2}
+    [
+      {firstname = "c"; lastname = "d"; score = 3};
+      {firstname = "a"; lastname = "b"; score = 1}
+    ] =
+    [
+      {firstname = "c"; lastname = "d"; score = 3};
+      {firstname = "e"; lastname = "f"; score = 2};
+      {firstname = "a"; lastname = "b"; score = 1}
+    ]);;
+(**/**)
+
+(** [records_insertion_sort l] sorts list of records [l] in ascending order *)
+let rec sort_records l =
+  match l with
+  | [] -> []
+  | x :: xs -> records_insert x (sort_records xs);;
+
+(**/**)
+let test_sort_records () =
+  assert (sort_records [] = []);
+  assert (sort_records
+    [{firstname = "a"; lastname = "b"; score = 1}] =
+    [{firstname = "a"; lastname = "b"; score = 1}]);
+
+  assert (sort_records [
+    {firstname = "c"; lastname = "d"; score = 3};
+    {firstname = "a"; lastname = "b"; score = 1};
+    {firstname = "e"; lastname = "f"; score = 2};
+  ] = [
+    {firstname = "c"; lastname = "d"; score = 3};
+    {firstname = "e"; lastname = "f"; score = 2};
+    {firstname = "a"; lastname = "b"; score = 1};
+  ]);;
+(**/**)
+
+(** [parse l] takes in a line [l] and parses the line to extract
+  * firstname, lastname, and score, returning Some record if successful
+  * or None if the input line [l] contains bad data *)
+let rec parse l =
+  try
+    Scanf.sscanf l " %s %s %s" (fun f l s ->
+      match int_of_string_opt s with
+      | Some v when v >= 0 && v <= 100 -> Some {firstname = f; lastname = l; score = v}
+      | _ -> None
+    )
+  with
+  | Scanf.Scan_failure _ -> None;;
+
+(**/**)
+let test_parse () =
+  assert (parse "" = None);
+  assert (parse "Bart simpson 5abc" = None);
+  assert (parse "Lisa simpson 130" = None);
+  assert (parse "Homer Simpson -5" = None);
+  assert (parse "Homer Simpson 5" =
+    Some {firstname = "Homer"; lastname = "Simpson"; score = 5});
+  assert (parse "Homer Simpson 5 blah blah blah" =
+    Some {firstname = "Homer"; lastname = "Simpson"; score = 5});;
+(**/**)
+
+(** [read_file acc ic] takes in an accumulator [acc] and an input channel [ic]
+  * and oterates over it input channel [ic] to parse each line and store the
+  * parsed result into the accumulator [acc] *)
+let rec read_file acc ic =
+  try
+    match parse @@ input_line ic with
+    | None -> read_file acc ic
+    | Some v -> read_file (v :: acc) ic
+  with
+  | End_of_file -> close_in ic; acc;;
+
+(**/**)
+let test_read_file () =
+  assert (read_file [] @@ open_in "data.txt" = [
+    {firstname = "gary"; lastname = "chalmers"; score = 5};
+    {firstname = "waylon"; lastname = "smithers"; score = 100};
+    {firstname = "homer"; lastname = "simpson"; score = 25};
+  ]);
+  assert (read_file [] @@ open_in "data1.txt" = [
+    {firstname = "gary"; lastname = "chalmers"; score = 5};
+    {firstname = "waylon"; lastname = "smithers"; score = 100};
+    {firstname = "ned"; lastname = "flanders"; score = 12};
+    {firstname = "homer"; lastname = "simpson"; score = 25};
+  ]);
+  assert (read_file [] @@ open_in "data2.txt" = []);;
+(**/**)
+
+(**/**)
+let run_all_tests () =
+  test_parse();
+  test_read_file();
+  test_compare_records();
+  test_records_insert();
+  test_sort_records();;
+(**/**)
+
+(** main program entry from cli *)
+let () =
+  if Array.length Sys.argv = 1 then
+    Printf.printf "%s: expects 1 file input.\nUsage: \"%s <filename>\"\n" Sys.argv.(0) Sys.argv.(0)
+  else
+    let ic = open_in Sys.argv.(1) in
+    print_records @@ sort_records @@ read_file [] ic;;