RE: :Text::FindAndReplaceAll()

>>Seems like a bug in the FindNext subroutine of Tk::Text. Basically using (.)
>>or (.*) doesn't seem to work properly.
>
>Someone (Greg London?) re-wrote this bit of TextUndo and I am not sure
>I know how it is supposed to work.

Yeah, that was me, in a previous life.
 
When you hit "ReplaceAll", it calls FindAndReplaceAll in  Tk::Text.
that is a very short routine which looks like this:
 
sub FindAndReplaceAll
{
   my ($w, $mode, $case, $find, $replace)=@_;
   $w->markSet('insert', '1.0');
   $w->unselectAll;
   while($w->FindNext('-forward', $mode, $case, $find))
      {
      $w->ReplaceSelectionWith($replace);
      }
}
 
The FindNext method uses the "search" method,
(not sure where it is defined, I'm a little rusty)
which takes in 
($direction, $mode, $case, count, "--",  $pattern, 'insert').
 
I think search is a low level function somewhere, 
but I don't remember.
 
Apparently, the while loop is stuck for some reason.
 
The FindNext method has a bit that says
 
$start_index = $w->search(
   $direction,
   $mode,
   -count ...
   "--",
   $pattern,
  'insert')
 
and then returns if start_index is not defined
of if its length as a string is 0.
 
apparently, it isn't returning 0, so the while loop never
exits.   
 
As I said, I'm a little rusty, it feels like its been several
years since I looked at this code.  Hopefully the above
will point someone in the right location to look, though.
 
I can look at it when I get some tuits.
 
Greg London
 

________________________________

From: [email protected] on behalf of Nick Ing-Simmons
Sent: Thu 3/9/2006 4:10 PM
To: [email protected]
Cc: [email protected]; [email protected]
Subject: RE: :Text::FindAndReplaceAll()



Jack D. <[email protected]> writes:
>> -----Original Message-----
>> From: [email protected]
>> [mailto:[email protected]] On
>> Behalf Of ????? ????????
>> Sent: December 16, 2005 7:34 AM
>> To: [email protected]
>> Subject: Tk::Text::FindAndReplaceAll()
>>
>> I have a Tk::TextUndo widget. It has context menu which also
>> holds Replace option.
>> I put a single word 'gallo' as a text. Than choose Replace
>> (Direction: any, Mode: regexp, Case: any), put '.*' as a
>> pattern and whatever as a replacement. Push "ReplaceAll". Works fine.
>> Now I put as a text 'gallo' and from the next line 'ballo'.
>> Than choose Replace (Direction: any, Mode: regexp, Case:
>> any), put '.*' as a pattern and non-empty replacement. Push
>> "ReplaceAll". The result - application is hanged (100% CPU
>> consumption). Works fine however if replacement is empty.
>>
>> This wouldn't be the issue if
>> $text_undo->FindAndReplaceAll('-regexp', '-case', qr/.*/,
>> 'whatever'); didn't behave the same nasty way.

The Menu is just sugar for calling that code or something very like it,
so I am _glad_ they behave the same.

>>
>> Is it something I missed or is there a bug in Tk (ActivePerl
>> 5.8.7.813)?
>
>Seems like a bug in the FindNext subroutine of Tk::Text. Basically using (.)
>or (.*) doesn't seem to work properly.

Someone (Greg London?) re-wrote this bit of TextUndo and I am not sure
I know how it is supposed to work.


/./ or /.*/ are supposed to map to perl's normal regular expressions.
So /./ will NOT match the "\n" at end of the line, and /.*/ is allowed
to match nothing. This might surprise the Text code someway.

I seem to recall by original had to do some messy adding of \G and
adding (effect of) /cg to regexp and then manipulate pos().

Also perl/Tk is calling perl's re C code in a devious manner which may
well not be robust as perl's regexp engine changes over time.
If I haven't got the "make a copy" flags right then when length of string
changes it may re-start from wrong place.


>i.e. the program gets stuck in a while loop because the $saved_insert never
>matches the $compared_index in the source code. I have cc'd the ptk mailing
>list for their thoughts.

Will try and decipher what I have imported.

>
>Jack
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