bpo-35196: Optimize Squeezer's write() interception (GH-10454)

The new functionality of Squeezer.reload() is also tested, along with some general
re-working of the tests in test_squeezer.py.

Lib/idlelib/NEWS.txt

@@ -3,6 +3,8 @@ Released on 2019-10-20?
 ======================================
 
 
+bpo-35196: Speed up squeezer line counting.
+
 bpo-35208: Squeezer now counts wrapped lines before newlines.
 
 bpo-35555: Gray out Code Context menu entry when it's not applicable.

Lib/idlelib/editor.py

@@ -317,9 +317,6 @@ class EditorWindow(object):
         text.bind("<<zoom-height>>", self.ZoomHeight(self).zoom_height_event)
         text.bind("<<toggle-code-context>>",
                   self.CodeContext(self).toggle_code_context_event)
-        squeezer = self.Squeezer(self)
-        text.bind("<<squeeze-current-text>>",
-                  squeezer.squeeze_current_text_event)
 
     def _filename_to_unicode(self, filename):
         """Return filename as BMP unicode so diplayable in Tk."""

Lib/idlelib/pyshell.py

@@ -899,6 +899,9 @@ class PyShell(OutputWindow):
         if use_subprocess:
             text.bind("<<view-restart>>", self.view_restart_mark)
             text.bind("<<restart-shell>>", self.restart_shell)
+        squeezer = self.Squeezer(self)
+        text.bind("<<squeeze-current-text>>",
+                  squeezer.squeeze_current_text_event)
 
         self.save_stdout = sys.stdout
         self.save_stderr = sys.stderr

Misc/NEWS.d/next/IDLE/2018-12-27-17-46-42.bpo-35196.9E-xUh.rst

+Speed up squeezer line counting.