On Tue, 12 Jun 2018 02:35:57 +0200, Alexander Hall wrote:
> The diff below uses system(3) to call /usr/bin/clear, fiddling with
> *env() to make sure the current TERM value is propagated. The error
> handling is deliberately sparse, since I don't know what the reasonable
> error actions would be.
>
> It's quite possible there already exists a better function to call
> within the ksh code already, but I was unable to figure out which if so.
Using system() within ksh seems wrong. How about this instead?
- todd
Index: bin/ksh/emacs.c
===================================================================
RCS file: /cvs/src/bin/ksh/emacs.c,v
retrieving revision 1.84
diff -u -p -u -r1.84 emacs.c
--- bin/ksh/emacs.c 16 Jan 2018 17:17:18 -0000 1.84
+++ bin/ksh/emacs.c 16 Jun 2018 12:31:59 -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 +1027,20 @@ x_redraw(int limit)
char *cp;
x_adj_ok = 0;
- if (limit == -1)
+ if (limit == -2) {
+ char *term = str_val(global("TERM"));
+ int ret = -1;
+ if (term && *term) {
+ Source *sold = source;
+ ret = command("/usr/bin/clear", 0);
+ source = sold;
+ }
+ if (ret != 0)
+ x_e_putc('\n');
+ }
+ else if (limit == -1)
x_e_putc('\n');
- else
+ else if (limit >= 0)
x_e_putc('\r');
x_flush();
if (xbp == xbuf) {
Index: bin/ksh/ksh.1
===================================================================
RCS file: /cvs/src/bin/ksh/ksh.1,v
retrieving revision 1.200
diff -u -p -u -r1.200 ksh.1
--- bin/ksh/ksh.1 30 May 2018 21:20:52 -0000 1.200
+++ bin/ksh/ksh.1 16 Jun 2018 12:29:34 -0000
@@ -4690,6 +4690,10 @@ 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:
+Attempts to clears the screen by invoking
+.Xr clear 1
+and redraws the prompt and current input line.
.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
