diff --git a/src/modal.c b/src/modal.c
index 5447fde..91f31c3 100644
--- a/src/modal.c
+++ b/src/modal.c
@@ -145,11 +145,10 @@ write_reg(char r, char *reg)
 		char c, *cap = walk(reg);
 		if(*reg == '(' && reg[1] != ')') { /* tuple */
 			reg++;
-			while(reg < cap) {
+			while(reg < cap - 1) {
 				while((c = *reg) && !spacer(c))
 					*dst_++ = c, reg++;
-				*dst_++ = ' ';
-				*dst_++ = '(', reg++, depth++;
+				*dst_++ = ' ', *dst_++ = '(', reg++, depth++;
 			}
 		} else /* token */
 			while((c = *reg++) && !spacer(c))