Fix losing symbolic keys after resize (no input)

self.input_box almost always exists, so the previous patch didn't do
what I thought it did. Instead, use a proper flag. Try to do better with
resizes while in readline too.

canto_curses/screen.py

@@ -58,6 +58,9 @@ def __init__(self, callbacks, types = [InputBox, TagList]):
         self.window_types = types
 
         self.input_box = None
+        self.pseudo_input_box = None
+        self.in_readline = False
+        self.in_readline_resize = False
 
         self.stdscr = curses.initscr()
         if self.curses_setup() < 0:
@@ -170,11 +173,15 @@ def curs_set(self, n):
     # endwin() (i.e. resize).
 
     def curses_setup(self):
-        if not self.input_box:
+        if self.in_readline:
+            self.pseudo_input_box.keypad(0)
+            self.curs_set(1)
+        elif self.pseudo_input_box:
+            self.pseudo_input_box.nodelay(1)
+            self.pseudo_input_box.keypad(1)
             self.curs_set(0)
         else:
-            self.curs_set(1)
-            self.pseudo_input_box.keypad(0)
+            self.curs_set(0)
 
         try:
             curses.cbreak()
@@ -562,7 +569,14 @@ def input_callback(self, prompt, completions=True):
 
         self.pseudo_input_box.keypad(0)
 
+        self.in_readline = True
         r = raw_readline()
+        self.in_readline = False
+
+        if self.in_readline_resize:
+            self.in_readline_resize = False
+            self.resize()
+
         if not r:
             r = ""
 
@@ -660,6 +674,7 @@ def _readline_getc(self):
         if r == curses.KEY_BACKSPACE:
             r = ord("\b")
         elif r == curses.KEY_RESIZE:
+            self.in_readline_resize = True
             return
         elif chr(r) == '\t' and do_comp:
             self.input_box.rotate_completions()