New submission from Terry J. Reedy:
ConfigDialog uses nearl 20 tkinter Vars, and I expect to add more. The name of
each appears in at least 6 places.
In one of 'create tab frame' methods:
1. create the Var
2. use the Var with at least 1 tk widget
In AttachVarCallbacks method:
3, 4. attach trace with callback with derived name
self.varname.trace_add('write', self.VarChanged_varname)
In remove_var_callbacks method (with delete call already factored out):
5. include Var in for loop tuple, to remove callback with
"var.trace_remove('write', var.trace_info()[0][1])"
In callback definition:
6. def VarChanged_varname
The above uses the new trace method names that will be introduced in #22115,
which I expect will be applied first. (I might also replace
'VarChanged_' with 'var_changed_' or something shorter, but this is not
relevant here.)
I propose to consolidate 1, 3, & 4 by replacing AttachVarCallbacks with
def add_traced_var(varname):
"""Create var; bind to varname, append to list, and trace with callback.
varname must match use in caller and callback def.
"""
var = tk.StringVar(self.root)
setattr(self, varname, var)
self.vars.append(var)
cbsuffix = 'font' if varname.startswith('font') else varname
var.trace_add('write', self.getattr('VarChanged_' + cbsuffix))
The cbsuffix local takes care of the complication that the 3 'fontWxyz' vars
need the same callback. In any Var are not StringVars, add vartype parameter.
Each tab frame creation method would call add_traced_var within a varname loop.
The current varname tuple for 5. would be replaced with self.vars, which
should then be cleared. This will leave 3 name occurrences that must match
instead of 6.
---
I believe 1-6 is complete. Varnames are translated to config item names within
the callbacks, so do not have to match. For instance,
def VarChanged_spaceNum(self, *params):
value = self.spaceNum.get()
self.AddChangedItem('main', 'Indent', 'num-spaces', value)
translated 'spaceNum' to 'num-spaces'. On the other hand, I an not sure why
the difference. For back compatibility, config names are fixed. The varnames,
like method names, are internal to configdialog and can lowercased (PEP8) and
otherwised changed.
---
For testing, I will embed the add and delete methods in a dummy class with a
couple of dummy callbacks. Then add, introspect, delete, and introspect again.
----------
assignee: terry.reedy
messages: 269271
nosy: terry.reedy
priority: normal
severity: normal
stage: test needed
status: open
title: IDLE configdialog: reduce multiple references to Var names
type: enhancement
versions: Python 3.6
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Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue27388>
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