From a3e49a75f09540b5aef16e3fc71960e03307e6ee Mon Sep 17 00:00:00 2001
From: Simon Forman <sforman@hushmail.com>
Date: Sun, 10 May 2020 08:36:05 -0700
Subject: [PATCH] Update view of stack at start.

---
 joy/gui/controllerlistbox.py |  6 +++++-
 joy/gui/world.py             |  6 +++---
 trylb.py                     | 21 +++++++++++++++++++++
 3 files changed, 29 insertions(+), 4 deletions(-)
 create mode 100644 trylb.py

diff --git a/joy/gui/controllerlistbox.py b/joy/gui/controllerlistbox.py
index a4068fd..745f8c0 100644
--- a/joy/gui/controllerlistbox.py
+++ b/joy/gui/controllerlistbox.py
@@ -20,7 +20,7 @@
 '''
 from Tkinter import Listbox, SINGLE
 from Tkdnd import dnd_start
-from joy.utils.stack import list_to_stack
+from joy.utils.stack import iter_stack, list_to_stack
 
 
 class SourceWrapper:
@@ -137,6 +137,10 @@ class StackListbox(ControllerListbox):
         self.delete(0, 'end')
         self.insert(0, *self.stack)
 
+    def update_stack(self, stack):
+        self.stack = list(iter_stack(stack))
+        self._update()
+
     def dnd_commit(self, source, event):
         ControllerListbox.dnd_commit(self, source, event)
         self._update()
diff --git a/joy/gui/world.py b/joy/gui/world.py
index dfc0360..be6f61c 100644
--- a/joy/gui/world.py
+++ b/joy/gui/world.py
@@ -29,7 +29,7 @@ from inspect import getdoc
 from joy.joy import run
 from joy.library import HELP_TEMPLATE
 from joy.parser import Symbol
-from joy.utils.stack import iter_stack, stack_to_string
+from joy.utils.stack import stack_to_string
 from joy.utils.types import type_check
 from .utils import is_numerical
 
@@ -160,10 +160,10 @@ class StackWorld(StackDisplayWorld):
 
 	def set_viewer(self, viewer):
 		self.viewer = viewer
+		self.viewer.update_stack(self.stack)
 
 	def print_stack(self):
 		StackDisplayWorld.print_stack(self)
 		if self.viewer:
-			self.viewer.stack = list(iter_stack(self.stack))
-			self.viewer._update()
+			self.viewer.update_stack(self.stack)
 
diff --git a/trylb.py b/trylb.py
new file mode 100644
index 0000000..bbb0ab2
--- /dev/null
+++ b/trylb.py
@@ -0,0 +1,21 @@
+from Tkinter import Tk, mainloop, BOTH
+from joy.gui.controllerlistbox import ControllerListbox
+
+
+class StackListbox(ControllerListbox):
+
+    def _update(self):
+        self.delete(0, 'end')
+        self.insert(0, *self.stack)
+
+    def dnd_commit(self, source, event):
+        ControllerListbox.dnd_commit(self, source, event)
+        self._update()
+
+    
+T = Tk()
+T.title("Hello there.")
+stack = [1, 2, 3]
+lb = FooListbox(T, items=stack)
+lb.pack(expand=True, fill=BOTH)
+lb._update()