New submission from Terry J. Reedy:
configdialog.ConfigDialog creates about 20 tk Variables corresponding to
configuration options. It defines a var_changed_xyz callback for each xyz
variable. 6 have a common template. ConfigDialog turns tracing on in
attach_var_callbacks and off in remove_var_callbacks. Each of these two
functions has the callbacks set hard-coded.
Proposal: Factor out what can. Register callbacks in set when var created.
Iterate register to attach and remove callbacks. Something like
def IVariable:
changes = <instance of changes> # set externally somehow
var = set()
def register(self, callback)
if isinstance(callback, tuple):
self.callback = default_callback
self.args = callback
else:
self.callback = callback
self.vars.add()
def default_callback(self): # Used for 6 vars.
changes.add_item(*self.args, self.get())
@classmethod
def attach(cls):
for var in cls.vars:
var.trace_add('write', self.callback)
@classmethod
def remove(cls):
for var in cls.vars:
var.trace_remove('write', var.trace_info()[0][1])
cls.vars = set()
To get String/Int/BooleanVars, maybe this will work. (I have only toyed with
multiple inheritance.)
class IString(tk.StringVar, IVariable):
def __init__(self, callback).
StringVar.__init() # Possibly not needed with no value to pass.
self.register(callback)
----------
assignee: terry.reedy
components: IDLE
messages: 297703
nosy: terry.reedy
priority: normal
severity: normal
stage: test needed
status: open
title: IDLE: configdialog -- factor out Variable subclass
type: enhancement
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Python tracker <[email protected]>
<http://bugs.python.org/issue30853>
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