less/backport-makecheck-0029-Have-lt_screen-use-ANSI-sequences-for-bold-underline.patch

From 2c01af28e833131c9b27119095414b636a8a1474 Mon Sep 17 00:00:00 2001
From: Mark Nudelman <markn@greenwoodsoftware.com>
Date: Tue, 18 Oct 2022 23:00:39 -0700
Subject: [PATCH 25/48] Have lt_screen use ANSI sequences for bold, underline
 etc rather than custom sequences. Need to support ANSI anyway and having two
 mechanisms is unnecessarily complicated.

---
 lesstest/env.c       | 12 ++++++------
 lesstest/lt_screen.c | 46 +++++++++++++++++++++++++++++++-------------
 2 files changed, 39 insertions(+), 19 deletions(-)

diff --git a/lesstest/env.c b/lesstest/env.c
index 76d26d0..72c2023 100644
--- a/lesstest/env.c
+++ b/lesstest/env.c
@@ -73,13 +73,13 @@ static void env_setup(EnvBuf* env, char* const* prog_env, int interactive) {
 		{ "LESS_TERMCAP_ho", "\33h" },
 		{ "LESS_TERMCAP_ll", "\33l" },
 		{ "LESS_TERMCAP_mb", "\33b" },
-		{ "LESS_TERMCAP_md", "\33d" },
-		{ "LESS_TERMCAP_me", "\33E" },
-		{ "LESS_TERMCAP_se", "\33t" },
-		{ "LESS_TERMCAP_so", "\33s" },
+		{ "LESS_TERMCAP_md", "\33[1m" },
+		{ "LESS_TERMCAP_me", "\33[m" },
+		{ "LESS_TERMCAP_se", "\33[m" },
+		{ "LESS_TERMCAP_so", "\33[7m" },
 		{ "LESS_TERMCAP_sr", "\33r" },
-		{ "LESS_TERMCAP_ue", "\33v" },
-		{ "LESS_TERMCAP_uo", "\33u" },
+		{ "LESS_TERMCAP_ue", "\33[24m" },
+		{ "LESS_TERMCAP_us", "\33[4m" },
 		{ "LESS_TERMCAP_vb", "\33g" },
 		{ "LESS_TERMCAP_kr", terminfo.key_right ? terminfo.key_right : "" },
 		{ "LESS_TERMCAP_kl", terminfo.key_left ? terminfo.key_left : "" },
diff --git a/lesstest/lt_screen.c b/lesstest/lt_screen.c
index 723a0e9..6cfa348 100644
--- a/lesstest/lt_screen.c
+++ b/lesstest/lt_screen.c
@@ -211,6 +211,9 @@ static int screen_clear_attr(int attr) {
 	return 1;
 }
 
+// ------------------------------------------------------------------ 
+// lt_screen supports certain ANSI color values.
+// This simplifies testing SGR sequences with less -R.
 static int screen_set_color(int color) {
 	int ret = 0;
 	switch (color) {
@@ -219,17 +222,26 @@ static int screen_set_color(int color) {
 	case 5:
 	case 6:  ret = screen_set_attr(ATTR_BLINK); break;
 	case 7:  ret = screen_set_attr(ATTR_STANDOUT); break;
+	case 21:
 	case 22: ret = screen_clear_attr(ATTR_BOLD); break;
 	case 24: ret = screen_clear_attr(ATTR_UNDERLINE); break;
+	case 25: ret = screen_clear_attr(ATTR_BLINK); break;
+	case 27: ret = screen_clear_attr(ATTR_STANDOUT); break;
+	// case 38: break;
+	// case 48: break;
 	default: 
-		if (color < 0)
+		if (color < 0) {
 			screen.curr_fg_color = screen.curr_bg_color = NULL_COLOR;
-		else if ((color >= 30 && color <= 37) || (color >= 90 && color <= 97))
+			ret = 1;
+		} else if ((color >= 30 && color <= 37) || (color >= 90 && color <= 97)) {
 			screen.curr_fg_color = color;
-		else if ((color >= 40 && color <= 47) || (color >= 100 && color <= 107))
+			ret = 1;
+		} else if ((color >= 40 && color <= 47) || (color >= 100 && color <= 107)) {
 			screen.curr_bg_color = color;
-		else
-			fprintf(stderr, "unrecognized color %d\n", color);
+			ret = 1;
+		} else {
+			fprintf(stderr, "[%d,%d] unrecognized color %d\n", screen.cx, screen.cy, color);
+		}
 		if (verbose) fprintf(stderr, "[%d,%d] set_color(%d)=%d/%d\n", screen.cx, screen.cy, color, screen.curr_fg_color, screen.curr_bg_color);
 		break;
 	}
@@ -282,25 +294,33 @@ static int exec_esc(wchar ch) {
 		return screen_rscroll();
 	case '<': // cursor left to start of line
 		return screen_cr();
-	case 's': // enter standout
-		return screen_set_attr(ATTR_STANDOUT);
-	case 't': // exit standout
-		return screen_clear_attr(ATTR_STANDOUT);
+#if 1
 	case 'u': // enter underline
+fprintf(stderr, "DEPRECATED ESC-%c\n", (char)ch);
 		return screen_set_attr(ATTR_UNDERLINE);
 	case 'v': // exit underline
+fprintf(stderr, "DEPRECATED ESC-%c\n", (char)ch);
 		return screen_clear_attr(ATTR_UNDERLINE);
 	case 'd': // enter bold
+fprintf(stderr, "DEPRECATED ESC-%c\n", (char)ch);
 		return screen_set_attr(ATTR_BOLD);
+	case 'E': // exit bold/blink
+fprintf(stderr, "DEPRECATED ESC-%c\n", (char)ch);
+		return screen_clear_attr(ATTR_BOLD|ATTR_BLINK);
+	case 's': // enter standout
+fprintf(stderr, "DEPRECATED ESC-%c\n", (char)ch);
+		return screen_set_attr(ATTR_STANDOUT);
+	case 't': // exit standout
+fprintf(stderr, "DEPRECATED ESC-%c\n", (char)ch);
+		return screen_clear_attr(ATTR_STANDOUT);
+#endif
 	case 'e': // exit bold
 		return screen_clear_attr(ATTR_BOLD);
 	case 'b': // enter blink
 		return screen_set_attr(ATTR_BLINK);
 	case 'c': // exit blink
 		return screen_clear_attr(ATTR_BLINK);
-	case 'E': // exit bold/blink
-		return screen_clear_attr(ATTR_BOLD|ATTR_BLINK);
-	case 'm': // set color
+	case 'm': // SGR (Select  Graphics Rendition)
 		if (num_params() == 0) {
 			screen_set_color(-1);
 		} else {
@@ -346,7 +366,7 @@ static int process_char(wchar ch) {
 		} else if (ch == ';') {
 			param_push(0);
 		} else if (ch == '[') {
-			; // ANSI sequence
+			; // Ignore ANSI marker
 		} else {
 			screen.in_esc = 0;
 			ok = exec_esc(ch);
-- 
2.27.0