Issue #21940: add docstrings to idlelib.WidgetRedirector.

This commit is contained in:
Terry Jan Reedy 2014-07-10 01:16:49 -04:00
parent 740c730086
commit 7cca28ffa2
1 changed files with 60 additions and 18 deletions

View File

@ -1,7 +1,6 @@
from tkinter import *
from tkinter import TclError
class WidgetRedirector:
"""Support for redirecting arbitrary widget subcommands.
Some Tk operations don't normally pass through Tkinter. For example, if a
@ -18,12 +17,22 @@ class WidgetRedirector:
this command and provide a facility ('register') to intercept the widget
operation.
In IDLE, the function being registered provides access to the top of a
Percolator chain. At the bottom of the chain is a call to the original
Tk widget operation.
In IDLE, WidgetRedirector is used in Percolator to intercept Text
commands. The function being registered provides access to the top
of a Percolator chain. At the bottom of the chain is a call to the
original Tk widget operation.
"""
def __init__(self, widget):
'''Initialize attributes and setup redirection.
_operations: dict mapping operation name to new function.
widget: the widget whose tcl command is to be intercepted.
tk: widget.tk, a convenience attribute, probably not needed.
orig: new name of the original tcl command.
Since renaming to orig fails with TclError when orig already
exists, only one WidgetDirector can exist for a given widget.
'''
self._operations = {}
self.widget = widget # widget instance
self.tk = tk = widget.tk # widget's root
@ -40,22 +49,34 @@ class WidgetRedirector:
self.widget._w)
def close(self):
"Unregister operations and revert redirection created by .__init__."
for operation in list(self._operations):
self.unregister(operation)
widget = self.widget; del self.widget
orig = self.orig; del self.orig
widget = self.widget
tk = widget.tk
w = widget._w
# Restore the original widget Tcl command.
tk.deletecommand(w)
# restore the original widget Tcl command:
tk.call("rename", orig, w)
tk.call("rename", self.orig, w)
del self.widget, self.tk # Should not be needed
# if instance is deleted after close, as in Percolator.
def register(self, operation, function):
'''Return OriginalCommand(operation) after registering function.
Registration adds an instance function attribute that masks the
class instance method attribute. If a second function is
registered for the same operation, the first function is replaced.
'''
self._operations[operation] = function
setattr(self.widget, operation, function)
return OriginalCommand(self, operation)
def unregister(self, operation):
'''Return the function for the operation, or None.
Deleting the instance attribute unmasks the class attribute.
'''
if operation in self._operations:
function = self._operations[operation]
del self._operations[operation]
@ -88,14 +109,29 @@ class WidgetRedirector:
class OriginalCommand:
'''Callable for original tk command that has been redirected.
Returned by .register; can be used in the function registered.
redir = WidgetRedirector(text)
def my_insert(*args):
print("insert", args)
original_insert(*args)
original_insert = redir.register("insert", my_insert)
'''
def __init__(self, redir, operation):
'''Create .tk_call and .orig_and_operation for .__call__ method.
.redir and .operation store the input args for __repr__.
.tk and .orig copy attributes of .redir (probably not needed).
'''
self.redir = redir
self.operation = operation
self.tk = redir.tk
self.orig = redir.orig
self.tk_call = self.tk.call
self.orig_and_operation = (self.orig, self.operation)
self.tk = redir.tk # redundant with self.redir
self.orig = redir.orig # redundant with self.redir
# These two could be deleted after checking recipient code.
self.tk_call = redir.tk.call
self.orig_and_operation = (redir.orig, operation)
def __repr__(self):
return "OriginalCommand(%r, %r)" % (self.redir, self.operation)
@ -104,7 +140,10 @@ class OriginalCommand:
return self.tk_call(self.orig_and_operation + args)
def _widget_redirector(parent):
def _widget_redirector(parent): # htest #
from tkinter import Tk, Text
import re
root = Tk()
root.title("Test WidgetRedirector")
width, height, x, y = list(map(int, re.split('[x+]', parent.geometry())))
@ -113,13 +152,16 @@ def _widget_redirector(parent):
text.pack()
text.focus_set()
redir = WidgetRedirector(text)
global previous_tcl_fcn
def my_insert(*args):
print("insert", args)
previous_tcl_fcn(*args)
previous_tcl_fcn = redir.register("insert", my_insert)
original_insert(*args)
original_insert = redir.register("insert", my_insert)
root.mainloop()
if __name__ == "__main__":
import unittest
## unittest.main('idlelib.idle_test.test_widgetredir',
## verbosity=2, exit=False)
from idlelib.idle_test.htest import run
run(_widget_redirector)