added ability to read arrow keys (escape sequences)

lesh

@@ -135,15 +135,21 @@ quit() {
 }
 
 # infinite loop waiting for single character input
+# or escape sequences from (e.g) arrow keys
 key_loop() {
     while read -rs -n 1; do
+        # when escape recieved, read any characters sent immediately after
+        # if there are none, then the escape key was pressed, but is ignored
+        if [ "$REPLY" = $'\e' ]; then
+            read -rs -t 0.0001
+        fi
         case $REPLY in
-            k)
+            k|"[A")
                 # if at start of the text, do nothing
                 [ ! "$line" = 0 ] && scroll_up
                 draw_prompt
                 ;;
-            j)
+            j|"[B")
                 # if at the end of text, do nothing
                 [ ! "$line" -ge $((${#text[@]}-scroll_size)) ] && scroll_down
                 draw_prompt