Ada 95 Check if enter was pressed - ada

Question

I am new to Ada.
How can I 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;

Answer 1

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;