gh-75733: Show IDLE's trees in a ttk.Treeview

idlelib.tree drew its rows on a canvas, with hardcoded pixel sizes that
fit neither every font nor every monitor, an icon on every row, and
bindings of its own for clicks and scrolling.  It now wraps a
ttk.Treeview, which takes its row height from the configured font and
its indicators, colors and keys from ttk and the theme.

Converted: the Module and Path browsers, Debug => Stack Viewer, the
object browsers, and the stack, Locals and Globals panes of the Debug
Control window.  Rows carry more than a text now: an item fills the
columns of its row with GetValues, and says with GetTags what kind of
row it is, which is how the stack views show a frame as module,
function, line and source, and how the Path Browser tells a directory,
a package and a module apart.

The stack pane of the debugger marks the frame it stopped in with a
drawn arrow instead of a "> " in front of the text.  The Locals and
Globals panes are read-only tables, as editing them never reached the
objects in the user process (gh-69184).  The Module Browser shows no
icons, its text saying already whether a row is a class or a function
(gh-69277).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: serhiy-storchaka

Lib/idlelib/Icons/README.txt

@@ -44,8 +44,8 @@ https://www.python.org/psf/trademarks-faq/
 https://www.python.org/psf/trademarks/  # Usage.
 
 
-OTHER GIFS: These are used by browsers using idlelib.tree.
-At least some will not be used when tree is replaced by ttk.Treeview.
+OTHER GIFS: folder, openfolder and python mark the directories, the
+packages and the modules of the Path Browser.
 
 
 Edited 2024 August 26 by TJR.

Lib/idlelib/Icons/minusnode.gif

@@ -12,9 +12,8 @@
 import pyclbr
 import sys
 
-from idlelib.config import idleConf
 from idlelib import pyshell
-from idlelib.tree import TreeNode, TreeItem, ScrolledCanvas
+from idlelib.tree import TreeItem, TreeWidget
 from idlelib.util import py_extensions
 from idlelib.window import ListedToplevel
 
@@ -96,9 +95,8 @@ def __init__(self, master, path, *, _htest=False, _utest=False):
         self.init()
 
     def close(self, event=None):
-        "Dismiss the window and the tree nodes."
+        "Dismiss the window."
         self.top.destroy()
-        self.node.destroy()
 
     def init(self):
         "Create browser tkinter widgets, including the tree."
@@ -117,25 +115,23 @@ def init(self):
             top.geometry("+%d+%d" %
                 (root.winfo_rootx(), root.winfo_rooty() + 200))
         self.settitle()
-        top.focus_set()
-
-        # create scrolled canvas
-        theme = idleConf.CurrentTheme()
-        background = idleConf.GetHighlight(theme, 'normal')['background']
-        sc = ScrolledCanvas(top, bg=background, highlightthickness=0,
-                            takefocus=1)
-        sc.frame.pack(expand=1, fill="both")
-        item = self.rootnode()
-        self.node = node = TreeNode(sc.canvas, None, item)
+
+        # create the tree
+        self.tree = tree = TreeWidget(top, self.rootnode())
+        tree.pack(expand=True, fill="both")
+        self.set_icons()
+        tree.focus_set()
         if not self._utest:
-            node.update()
-            node.expand()
+            tree.expand()
 
     def settitle(self):
         "Set the window title."
         self.top.wm_title("Module Browser - " + os.path.basename(self.path))
         self.top.wm_iconname("Module Browser")
 
+    def set_icons(self):
+        "Give the rows icons.  The module browser shows none; see gh-69277."
+
     def rootnode(self):
         "Return a ModuleBrowserTreeItem as the root of the tree."
         return ModuleBrowserTreeItem(self.path)
@@ -160,14 +156,14 @@ def GetText(self):
         "Return the module name as the text string to display."
         return os.path.basename(self.file)
 
-    def GetIconName(self):
-        "Return the name of the icon to display."
-        return "python"
-
     def GetSubList(self):
         "Return ChildBrowserTreeItems for children."
         return [ChildBrowserTreeItem(obj) for obj in self.listchildren()]
 
+    def GetTags(self):
+        "Mark the row as a module, which the Path Browser gives an icon."
+        return ('module',)
+
     def OnDoubleClick(self):
         "Open a module in an editor window when double clicked."
         if not is_browseable_extension(self.file):
@@ -213,13 +209,6 @@ def GetText(self):
         else:
             return "class " + name
 
-    def GetIconName(self):
-        "Return the name of the icon to display."
-        if self.isfunction:
-            return "python"
-        else:
-            return "folder"
-
     def IsExpandable(self):
         "Return True if self.obj has nested objects."
         return self.obj.children != {}
@@ -244,7 +233,7 @@ def _module_browser(parent): # htest #
     else:
         file = __file__
         # Add nested objects for htest.
-        class Nested_in_func(TreeNode):
+        class Nested_in_func(TreeItem):
             def nested_in_class(): pass
         def closure():
             class Nested_in_closure: pass