From 1c0db7e5da3dc0398820405b8646577adefb41e3 Mon Sep 17 00:00:00 2001
From: Timothy Warren <twarren@nabancard.com>
Date: Wed, 21 Aug 2019 08:45:19 -0400
Subject: [PATCH] Handle displaying control characters better

---
 kilo.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/kilo.c b/kilo.c
index 7bf97ff..fdfca31 100644
--- a/kilo.c
+++ b/kilo.c
@@ -997,7 +997,22 @@ void editorDrawRows(struct abuf *ab)
 			int j;
 			for (j = 0; j < len; j++)
 			{
-				if (hl[j] == HL_NORMAL)
+				// Make control characters "readable"
+				if (iscntrl(c[j]))
+				{
+					char sym = (c[j] <= 26) ? '@' + c[j] : '?';
+					abAppend(ab, "\x1b[7m", 4);
+					abAppend(ab, &sym, 1);
+					abAppend(ab, "\x1b[m", 3);
+					// Restore the previous highlighting color
+					if (current_color != -1)
+					{
+						char buf[16];
+						int clen = snprintf(buf, sizeof(buf), "\x1b[%dm", current_color);
+						abAppend(ab, buf, clen);
+					}
+				}
+				else if (hl[j] == HL_NORMAL)
 				{
 					if (current_color != -1)
 					{