Okay, I got it working better, but it's still buggy. I fixed the bug that prevented cursor keys from working. Also, delete and backspace function normally now (without causing undue cursor movement), although backspace still goes left rather than right, and vice versa. The proper text direction is more reliable, but still committing errors. When I type "This is a test.", I invariably wind up with " .tseta si sihT". The cursor fails to move left on the space following the "a" every single time I type that sentence. If somebody can figure this out, I'd be grateful, as I am now quite interested in solving this problem. 
#!/usr/bin/perl
use strict;
use warnings;
use Tk;

my $last=1.0;
my $mw = MainWindow->new(
    -background=>"darkviolet"
    );


my $t1 = $mw->Text(
       -background=>"navy",
       -foreground=>"white",
       -height=>35,
       -width=>80,
       -wrap=>"word",
       -selectbackground=>"blueviolet"
       )->pack;
$t1->bind("<Key>" => \&rtl);
#$t1->bind("<KeyRelease>" => sub {$t1->SetCursor('insert - 1 chars')})
+;

sub rtl {
    my $size = $t1->index('end - 1 chars');
    if ($last < $size) {
        $t1->SetCursor('insert - 1 chars');
    }
    $last = $size;
}

MainLoop;

[download]

edit: Got it! This error occurs on the 10th character of the line, and repeats at the 100th. Our comparison is saying that 1.9 is not less than 1.10 and 1.99 is not less than 1.100. True for integers, but not for line.word count.

--
Linux, sci-fi, and Nat Torkington, all at Penguicon 3.0

In reply to Re^2: right to left Tk text widget by wolfger
in thread right to left Tk text widget by davidj

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.