#!/usr/bin/env python
"""If Text search is called from
a variable trace then the count variable
is not be updated.

I see this with Python 2.4.3 and Aqua Tcl/Tk 8.4.11
on MacOS X 10.4.7. I have not tested it elsewhere.

Note that this works fine in tcl/tk
(see tcl procedure at end of doc string)
so this appears to be a Tkinter issue.

To see the problem:
- Run this python file.
- Enter text in the Entry widget;
- If the text exists in the Text widget
  you'll see a valid begInd, but count is always zero.

It works correctly if the trace uses "after".
To see this:
- Modify the trace to call okSearch instead of doSearch/
- Repeat the test just listed.


Also, here is the equivalent tcl/tk procedure
(which *does* work)

wish
text .t
pack .t
.t tag configure found -background "light green"
.t insert end "Line 1 of sample text\n"
.t insert end "Line 2 of sample text\n"
.t insert end "More text\n"
.t insert end "Yet more text\n"
.t insert end "One more line of text\n"
entry .e -textvariable evar
pack .e
trace variable evar w dosearch

proc dosearch {var dum1 dum2} {
	global evar
	global .t
	puts "evar = $evar"
	set begind [.t search -count cnt $evar 1.0 end]
	puts "found $evar begind = $begind cnt = $cnt"
}
"""
from Tkinter import *

root = Tk()
t = Text()
t.pack()
evar = StringVar()
e = Entry(textvariable = evar)
e.pack()

def doSearch(*args):
	var = IntVar()
	var.set(0)
	searchStr = evar.get()
	begInd = t.search(searchStr, "0.0", count=var)
	print "begInd = %r; count = %r" % (begInd, var.get())
	
def okSearch(*args):
	t.after(1, doSearch)

evar.trace_variable("w", doSearch)

t.insert("end", "Line 1 of sample text\n")
t.insert("end", "Line 2 of sample text\n")
t.insert("end", "More text\n")
t.insert("end", "Yet more text\n")
t.insert("end", "One more line of text\n")

root.mainloop()