On 6/06/2018, at 10:20 AM, Alexander Hall wrote:
> This adds a "clear-screen" editing command to the emacs editing mode.
> This is the same name as bash and zsh uses, and then I stopped looking.
>
> Thoughts? OK?
It's unclear to me what need is being being addressed here --- are you
wanting a way to quickly hide sensitive info typed by mistake at a
commandline?
^Cclear^M is available, of course, or ^A^K, or the "bind -m '^L'=^Uclear'^J^Y'"
that benno@ mentioned. On the console, one can switch VT. I suppose some
window managers offer short-cuts to "lock screen", or can switch virtual
desktops, or minimise the window.
Yes, I could see how the patch might be warranted if this occured
frequently, but how often do you find yourself needing it? Often enough
to be annoyed by the side-effects you mentioned of benno's key binding?
It seems to me this patch would make ksh into a screen-orientated shell
for the sake of reimplementing a rarely-used shortcut.
best,
Richard.
>
>
> /Alexander
>
>
> Index: emacs.c
> ===================================================================
> RCS file: /cvs/src/bin/ksh/emacs.c,v
> retrieving revision 1.84
> diff -u -p -r1.84 emacs.c
> --- emacs.c 16 Jan 2018 17:17:18 -0000 1.84
> +++ emacs.c 5 Jun 2018 22:03:49 -0000
> @@ -146,6 +146,7 @@ static int isu8cont(unsigned char);
> /* proto's for keybindings */
> static int x_abort(int);
> static int x_beg_hist(int);
> +static int x_clear_screen(int);
> static int x_comp_comm(int);
> static int x_comp_file(int);
> static int x_complete(int);
> @@ -202,6 +203,7 @@ static int x_debug_info(int);
> static const struct x_ftab x_ftab[] = {
> { x_abort, "abort", 0 },
> { x_beg_hist, "beginning-of-history", 0 },
> + { x_clear_screen, "clear-screen", 0 },
> { x_comp_comm, "complete-command", 0 },
> { x_comp_file, "complete-file", 0 },
> { x_complete, "complete", 0 },
> @@ -1004,12 +1006,19 @@ x_draw_line(int c)
> {
> x_redraw(-1);
> return KSTD;
> +}
>
> +static int
> +x_clear_screen(int c)
> +{
> + x_redraw(-2);
> + return KSTD;
> }
>
> -/* Redraw (part of) the line. If limit is < 0, the everything is redrawn
> - * on a NEW line, otherwise limit is the screen column up to which needs
> - * redrawing.
> +/* Redraw (part of) the line.
> + * A non-negative limit is the screen column up to which needs
> + * redrawing. A limit of -1 redraws on a new line, while a limit
> + * of -2 (attempts to) clear the screen.
> */
> static void
> x_redraw(int limit)
> @@ -1018,9 +1027,15 @@ x_redraw(int limit)
> char *cp;
>
> x_adj_ok = 0;
> - if (limit == -1)
> + if (limit == -2) {
> + char *clearstr = str_val(global("CLEARSTR"));
> + if (clearstr == null)
> + clearstr = "\033[H\033[J";
> + x_e_puts(clearstr);
> + }
> + else if (limit == -1)
> x_e_putc('\n');
> - else
> + else if (limit >= 0)
> x_e_putc('\r');
> x_flush();
> if (xbp == xbuf) {
> Index: ksh.1
> ===================================================================
> RCS file: /cvs/src/bin/ksh/ksh.1,v
> retrieving revision 1.200
> diff -u -p -r1.200 ksh.1
> --- ksh.1 30 May 2018 21:20:52 -0000 1.200
> +++ ksh.1 5 Jun 2018 22:03:49 -0000
> @@ -1345,6 +1345,8 @@ Also, the
> .Ic cd
> built-in command will display the resulting directory when a match is found
> in any search path other than the empty path.
> +.It Ev CLEARSTR
> +If set, overrides the default escape sequence to clear the screen.
> .It Ev COLUMNS
> Set to the number of columns on the terminal or window.
> Currently set to the
> @@ -4690,6 +4692,12 @@ Moves the cursor to the beginning of the
> Uppercase the first character in the next
> .Ar n
> words, leaving the cursor past the end of the last word.
> +.It clear-screen:
> +Clears the screen and redraws the prompt and current input line.
> +If the
> +.Ev CLEARSTR
> +parameter is set, it is used to clear the screen.
> +Otherwise, a default escape sequence (^[[H^[2J) is used.
> .It comment: ^[#
> If the current line does not begin with a comment character, one is added at
> the beginning of the line and the line is entered (as if return had been
>
