Why is "f" printed?

I would have expected the question 'why are "f" and "g" printed'. Do you agree that printing "g" is also surprising, for the same reason? (If not, I may be misunderstanding random parts of your post.)

Why is there the empty regex (see (*))?

I don't know, seems very odd to me. I suggest reporting it as a possible bug.

It seems possible that since the last successfully matched regexp was /d/, and the last attempted match against that regexp was a fail, it may have somehow marked it as no longer successfully matched; but that doesn't explain the change of behaviour when you add the empty continue block.

I suspect rather that it is a scoping bug: I'm not sure if the docs make this clear, but it is intended to use the last successfully matched regexp visible to the current scope. Thus:

% perl -wle '"a" =~ /a/; { "b" =~ /b/ } "ab" =~ // and print $&'
a
%

[download]

FWIW p5p mostly regards the empty regexp behaviour as a misfeature reluctantly spared the axe only because of the constraints of backward compatibility - it is very rare to see anyone actually trying to make use of it. But since we have it, it certainly ought to work as advertised.

In reply to Re: Empty pattern in regex by hv
in thread Empty pattern in regex by choroba

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.