Ada 95 Check if enter was pressed

The while loop should be able to check whether the input character is a white space or an enter key.

Furthermore, how can I check the user input type, like the type() or typeof() function in other languages?

FUNCTION ReadValue RETURN Unbounded_String IS
      ValueChar : Character;
      Result : Unbounded_String := To_Unbounded_String("NULL");
   BEGIN
      Get(ValueChar);
      Skip_Line;
      
      WHILE ValueChar /= ';'LOOP
         Get(ValueChar);
         IF IsValidNameInput(ValueChar) THEN 
            Result := Result & ValueChar;
         ELSE
            exit;
         END IF;         
      END LOOP;
      ValueIntegerFlag  := CheckValue(Value);
      
      RETURN Result;
      
   END ReadValue; 

Read the characters one-at-a-time without special ENTER handling using Get_Immediate instead of Get - ARM A.10.7(9).

You can do checks on the class of the character you’ve just read using Ada.Characters.Handling - ARM A.3.2 - something like

function Is_Valid_Name_Input (Ch : Character) return Boolean is
begin
   return Ada.Characters.Handling.Is_Graphic (Ch)
     and then not Ada.Characters.Handling.Is_Space (Ch);
end Is_Valid_Name_Input;

(probably not quite what you want, since it makes &*^$$^ a valid name!)

Ada.Characters.Handling.Is_Line_Terminator detects ENTER (on Unix; probably on Windows too).

You can check whether a string corresponds to an integer by trying the conversion and catching the exception when it fails:

function Check_Integer_Value (Str : Unbounded_String) return Boolean is
   Dummy : Integer;
begin
   Dummy := Integer'Value (To_String (Str));
   return True;
exception
   when Constraint_Error =>
      return False;
end Check_Integer_Value;

With regard to ReadValue:

• Don’t initialize Result - it starts off as the empty string (and you really don’t want to start with the string ”NULL”).
• It skips the first character input.
• What’s that Skip_Line for?

Try something like

function Read_Value return Unbounded_String is
   Value_Char : Character;
   Result : Unbounded_String;
begin
   loop
      Get_Immediate (Value_Char);
      exit when Value_Char = ';';
      if Is_Valid_Name_Input (Value_Char) then
         Result := Result & Value_Char;
      end if;
   end loop;
   return Result;
end Read_Value;