yterm

diff --git a/source/interpreter/vt100.c b/source/interpreter/vt100.c
index 01c7fc4023e4851e219c7f30bfa24fa0c82ad7d1..8816d3b2a1c97e518c29e04e2984d10fc03ea97a 100644
--- a/source/interpreter/vt100.c
+++ b/source/interpreter/vt100.c
@@ -8,7 +8,8 @@ enum {
 	MODE_READY = 0,
 	MODE_ESCAPE,
 	MODE_CSI, // \e[
-	MODE_OSC  // \e]
+	MODE_OSC, // \e]
+	MODE_CHSET
 };
 
 enum {
@@ -406,7 +407,11 @@ 		case MODE_ESCAPE: {
 			switch (ch) {
 				case '[': this->mode = MODE_CSI; break;
 				case ']': this->mode = MODE_OSC; break;
-				default:  this->mode = MODE_READY; // invalid
+				case '(': this->mode = MODE_CHSET; break;
+				default: {
+					printf("Unimplemented: ESC '%c'\n", ch);
+					this->mode = MODE_READY; // invalid
+				}
 			}
 			break;
 		}
@@ -446,6 +451,10 @@ 			else {
 				char ch2 = (char) ch;
 				strncat(this->reading, &ch2, 1);
 			}
+			break;
+		}
+		case MODE_CHSET: {
+			this->mode = MODE_READY;
 			break;
 		}
 	}