Aha -- that does it. I like the approach much better (matching non-backslash and colon or 2-character escape sequences).

Running some quick test code: 

    my $re = shift or die "re expected\n";
    while (<>) {
        chomp;
        my ($field, $value) = ($_ =~ $re);
        print "'$_' -> ('$field', '$value')\n";
    }

[download]
We see that it handles all these cases correctly: 
 'a:b:c' -> ('a', 'b:c')
 'a\:b:c' -> ('a\:b', 'c')
 'a\\:b:c' -> ('a\\', 'b:c')
 'a\\\:b:c' -> ('a\\\:b', 'c')
 'a:' -> ('a', '')
 ':b' -> ('', 'b')

[download]
The only thing it doesn't handle perfectly is the invalid input case with an escaped colon but no delimiter: 
 
 'a\:b' -> ('', 'b')

[download]
Notice that this is indistinguishable from the ':b' input. The fix is simple though, just anchor the start of the match: 
 ^((?:[^:\\]+|\\.)*):(.*)

[download]
For my use this works better, as the match fails, telling me there was no field delimiter present.

Thanks
--mike

In reply to Re^2: Handling escapes while splitting lines by mikecarlton
in thread Handling escapes while splitting lines by mikecarlton

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.