How to get a key from keyboard

How to get a key from keyboard

[tolkamp]

In Pascal there is a function Readkey to read a single character from
the keyboard. Is there a simular function in ADA?
I have tried the procedure Get_Immediate(Char, Error) but here you
have to press the Enter key as well.

Re: How to get a key from keyboard

[Gautier]

tolkamp wrote:

> In Pascal there is a function Readkey to read a single character from
> the keyboard. Is there a simular function in ADA?

NB: ReadKey is a Turbo Pascal thing.

> I have tried the procedure Get_Immediate(Char, Error) but here you
> have to press the Enter key as well.

Strange... I get immediately each of "[a][b][c][d]..." when pressing 
each of "abcd...", with the following:
--
with Ada.Text_IO; use Ada.Text_IO;

procedure Test_Key is
   c: Character;
begin
   loop
     Get_Immediate(c);
     Put('[' & c & ']');
   end loop;
end Test_Key;
--
Compiled by GNAT, run on Windows.
_________________________________________________________
Gautier's Ada programming -- http://sf.net/users/gdemont/

NB: For a direct answer, e-mail address on the Web site!

Re: How to get a key from keyboard

[Paul]

The other version of get_immediate works fine for me (GNAT GPL 2008)

I always liked Turbo Pascal.  It was my uni's "learning language" back in 
the mid 80's.  Very fast on an 8086 computer!

If I were going to use the code below I'd probably use the Look_Ahead 
procedure as well.  I recall when I wrote some of this a while back that 
control codes and the like could be tricky.

Paul

with ada.text_io;use ada.text_io;
procedure chartest is
  ch : character := 'Y';
  available : boolean := false;
begin
  put_line("Enter characters");
  while ch /= 'X' loop
    get_immediate(ch, available);
    if available then
      put(ch);
    end if;
  end loop;
  new_line;
  put_line("Done");
end chartest;



"Gautier" <gautier@fakeaddress.nil> wrote in message 
news:49301282$1_1@news.bluewin.ch...
> tolkamp wrote:
>
>> In Pascal there is a function Readkey to read a single character from
>> the keyboard. Is there a simular function in ADA?
>
> NB: ReadKey is a Turbo Pascal thing.
>
>> I have tried the procedure Get_Immediate(Char, Error) but here you
>> have to press the Enter key as well.
>
> Strange... I get immediately each of "[a][b][c][d]..." when pressing each 
> of "abcd...", with the following:
> --
> with Ada.Text_IO; use Ada.Text_IO;
>
> procedure Test_Key is
>   c: Character;
> begin
>   loop
>     Get_Immediate(c);
>     Put('[' & c & ']');
>   end loop;
> end Test_Key;
> --
> Compiled by GNAT, run on Windows.
> _________________________________________________________
> Gautier's Ada programming -- http://sf.net/users/gdemont/
>
> NB: For a direct answer, e-mail address on the Web site! 

Re: How to get a key from keyboard

[christoph.grein]

A.10.7
 (9) procedure Get_Immediate(File : in File_Type;
                            Item : out Character);
     procedure Get_Immediate(Item : out Character);

(10) Reads the next character, either control or graphic, from the
specified File or the default input file. Mode_Error is propagated if
the mode of the file is not In_File. End_Error is propagated if at the
end of the file. The current column, line and page numbers for the
file are not affected.

(11) procedure Get_Immediate(File : in File_Type;
                             Item : out Character;
                             Available : out Boolean);
     procedure Get_Immediate(Item : out Character;
                             Available : out Boolean);

(12) If a character, either control or graphic, is available from the
specified File or the default input file, then the character is read;
Available is True and Item contains the value of this character. If a
character is not available, then Available is False and the value of
Item is not specified. Mode_Error is propagated if the mode of the
file is not In_File. End_Error is propagated if at the end of the
file. The current column, line and page numbers for the file are not
affected.

Thus the former procedures block if there is no character available,
the latter ones don't.

Try:

  loop
    get_immediate (C);
    Put (Integer'Image (Character'Pos (c)));
  end loop;

Which compiler do you use? If you run the above within GPS, you must
press <enter> - otherwise GPS obviously does not forward the input to
the executable (note that GPS echoes the input and you can edit the
input line with <backspace>). If you run it from a terminal window,
you can press any key and immediately get the result (for some keys,
you'll get more than one number) and there is no echo of your input
and no editing.

Re: How to get a key from keyboard

[f.tolkamp]

On 1 dec, 08:28, christoph.gr...@eurocopter.com wrote:
> A.10.7
>  (9) procedure Get_Immediate(File : in File_Type;
>                             Item : out Character);
>      procedure Get_Immediate(Item : out Character);
>
> (10) Reads the next character, either control or graphic, from the
> specified File or the default input file. Mode_Error is propagated if
> the mode of the file is not In_File. End_Error is propagated if at the
> end of the file. The current column, line and page numbers for the
> file are not affected.
>
> (11) procedure Get_Immediate(File : in File_Type;
>                              Item : out Character;
>                              Available : out Boolean);
>      procedure Get_Immediate(Item : out Character;
>                              Available : out Boolean);
>
> (12) If a character, either control or graphic, is available from the
> specified File or the default input file, then the character is read;
> Available is True and Item contains the value of this character. If a
> character is not available, then Available is False and the value of
> Item is not specified. Mode_Error is propagated if the mode of the
> file is not In_File. End_Error is propagated if at the end of the
> file. The current column, line and page numbers for the file are not
> affected.
>
> Thus the former procedures block if there is no character available,
> the latter ones don't.
>
> Try:
>
>   loop
>     get_immediate (C);
>     Put (Integer'Image (Character'Pos (c)));
>   end loop;
>
> Which compiler do you use? If you run the above within GPS, you must
> press <enter> - otherwise GPS obviously does not forward the input to
> the executable (note that GPS echoes the input and you can edit the
> input line with <backspace>). If you run it from a terminal window,
> you can press any key and immediately get the result (for some keys,
> you'll get more than one number) and there is no echo of your input
> and no editing.

Indeed I run the program within GPS, so the enter key have to be
pressed. How can I run the program from a terminal window?

Re: How to get a key from keyboard

[Georg Bauhaus]

f.tolkamp@chello.nl wrote:

> Indeed I run the program within GPS, so the enter key have to be
> pressed. How can I run the program from a terminal window?

Start a Windows terminal. In GPS, locate the project's objects
directory. (You can find it in the "Objects" tab of the project
properties.) In the terminal window, change directory to the
project's objects directory. Run your program.

When you have time, browse the GNAT User's Guide, linked
from the GPS help menu.