This demonstrates the (a?) difference. How you interprete the results relative to the descriptions I can't quite figure. 

 perl> $s = join'','a'..'z'

 perl> 1 while $s =~ m[((.).)(?{ print "$^N:$+\n"; })]g
ab:a
cd:c
ef:e
gh:g
ij:i
kl:k
mn:m
op:o
qr:q
st:s
uv:u
wx:w
yz:y


 perl> 1 while $s =~ m[((..).)(?{ print "$^N:$+\n"; })]g
abc:ab
def:de
ghi:gh
jkl:jk
mno:mn
pqr:pq
stu:st
vwx:vw

[download]

One interesting difference in the description that had me salivating breifly was that $+ is explicity defined read-only whereas (in your snippet) $^N it's not but whilst attempting to assign to it doesn't result in an error, it also has no effect on the bound string.

Examine what is said, not who speaks.
1) When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.
2) The only way of discovering the limits of the possible is to venture a little way past them into the impossible
3) Any sufficiently advanced technology is indistinguishable from magic.
Arthur C. Clarke.

In reply to Re: $+ versus $^N by BrowserUk
in thread $+ versus $^N by diotalevi

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.