http://qs1969.pair.com?node_id=588373


in reply to A graphical regular expression tester.

Hi reasonablekeith,

You should be aware that the following errors occur when matching the regex "a?Cd" against the data "abcdefg" (with no checkbuttons selected): 

Warning: Attempt to load 'Tk::Checkbutton::0.000503063201904297' at
 /usr/lib/perl5/site_perl/5.8.0/i386-linux-thread-multi/Tk/Widget.pm
 line 287 Tk::Widget::AUTOLOAD('Tk::Checkbutton=HASH(0x860c6a8)')
 called at /usr/lib/perl5/site_perl/5.8.0/i386-linux-thread-multi/Tk.p
+m
 line 406 eval {...} called at
 /usr/lib/perl5/site_perl/5.8.0/i386-linux-thread-multi/Tk.pm line 406
 Tk::MainLoop() called at x line 126

[download]
s''(q.S:$/9=(T1';s;(..)(..);$..=substr+crypt($1,$2),2,3;eg;print$..$/

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Re^2: A graphical regular expression tester.
by reasonablekeith (Deacon) on Dec 07, 2006 at 18:42 UTC
    Weird, your example tested fine until I clicked one of the switches, then got a similar error to you. However, I noticed the error didn't occur when clicking the checkbox for 'g'. The way subroutine call for this event is handled differently, so I swapped the following.... 
    
< $check_switch_i->bind('<Button-1>', \&button_run('now'));
< $check_switch_m->bind('<Button-1>', \&button_run('now'));
< $check_switch_s->bind('<Button-1>', \&button_run('now'));

> $check_switch_i->bind('<Button-1>', sub { button_run('now') });
> $check_switch_m->bind('<Button-1>', sub { button_run('now') });
> $check_switch_s->bind('<Button-1>', sub { button_run('now') });

    [download]
    ...and the bug has gone. I've no idea why though. Anyone?

    Cheers, Rob

    ---
    my name's not Keith, and I'm not reasonable.
[reply]
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      Hi reasonablekeith,

      Yes, it's because you're not doing what you think you're doing with: 

      $check_switch_i->bind('<Button-1>', \&button_run('now'));

      [download]

      If you run perl -MO=Deparse on that, it'll show you: 

      $check_switch_i->bind('<Button-1>', \(&button_run('now')));

      [download]

      Which means that you're calling bind with a reference to the results of a call to the subroutine button_run.

      What you want, instead (if you're going to use that style of notation), is the anonymous list syntax: 

      $check_switch_i->bind('<Button-1>', [ \&button_run, 'now' ]);

      [download]
      s''(q.S:$/9=(T1';s;(..)(..);$..=substr+crypt($1,$2),2,3;eg;print$..$/
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