commit e8392b282c2eaa28725241a9612804fb55113da4
from: Avi Halachmi (:avih) <avihpit@yahoo.com>
via: Hiltjo Posthuma <hiltjo@codemadness.org>
date: Sat May 16 12:08:10 2020 UTC

support REP (repeat) escape sequence

The sequence \e[Nb prints the last printed char N (more) times if it's
printable, and it's ignored after newline or other control chars.

This is Ecma-048/ANSI-X3.6 sequence and not DEC VT. It's supported by
xterm, and ncurses uses it when possible, e.g. when TERM is xterm* (and
with this commit also st*).

xterm supports only codepoints<=255, possibly due to internal limits.
We support any value/codepoint which was placed in a cell.

To test:
- tput rep 65 4 -> prints 'AAAA'
- printf "\342\225\246\033[4b" -> prints U+2566 1+4 times.

commit - f8afebdfa0cc9a57b22c39c47e9b585f69453eb7
commit + e8392b282c2eaa28725241a9612804fb55113da4
blob - 0d35613e04222564ab5fee489df6e1812b0a027f
blob + 54af09826c7389b4eac288273fb1aa121f471d76
--- st.c
+++ st.c
@@ -129,6 +129,7 @@ typedef struct {
 	int charset;  /* current charset */
 	int icharset; /* selected charset for sequence */
 	int *tabs;
+	Rune lastc;   /* last printed char outside of sequence, 0 if control */
 } Term;
 
 /* CSI Escape sequence structs */
@@ -1648,6 +1649,12 @@ csihandle(void)
 		if (csiescseq.arg[0] == 0)
 			ttywrite(vtiden, strlen(vtiden), 0);
 		break;
+	case 'b': /* REP -- if last char is printable print it <n> more times */
+		DEFAULT(csiescseq.arg[0], 1);
+		if (term.lastc)
+			while (csiescseq.arg[0]-- > 0)
+				tputc(term.lastc);
+		break;
 	case 'C': /* CUF -- Cursor <n> Forward */
 	case 'a': /* HPR -- Cursor <n> Forward */
 		DEFAULT(csiescseq.arg[0], 1);
@@ -2373,6 +2380,8 @@ check_control_code:
 		/*
 		 * control codes are not shown ever
 		 */
+		if (!term.esc)
+			term.lastc = 0;
 		return;
 	} else if (term.esc & ESC_START) {
 		if (term.esc & ESC_CSI) {
@@ -2422,6 +2431,7 @@ check_control_code:
 	}
 
 	tsetchar(u, &term.c.attr, term.c.x, term.c.y);
+	term.lastc = u;
 
 	if (width == 2) {
 		gp->mode |= ATTR_WIDE;
blob - d0694e229c84037a3b01c7518fe2eeb4568c7904
blob + e5393db18d41fd2d67ea07f6bc7b848af7cd37fc
--- st.info
+++ st.info
@@ -184,6 +184,7 @@ st-mono| simpleterm monocolor,
 # XTerm extensions
 	rmxx=\E[29m,
 	smxx=\E[9m,
+	rep=%p1%c\E[%p2%{1}%-%db,
 # tmux extensions, see TERMINFO EXTENSIONS in tmux(1)
 	Tc,
 	Ms=\E]52;%p1%s;%p2%s\007,