As was already pointed out, you can get implication already with: 
  (A and not B)

[download]
(just look at the truth-table). As for your example, it can be cleanly written with: 
  ($method ne "post") or ($contenttype eq "application/x-www-form-urle
+ncoded)

[download]
since you are never falling through the or unless the method is "post".

In fact I find the form I wrote easier to follow than the version with the implication operator that you asked for. There does come a time when offering many logically equivalent ways to say the same thing lends to confusion, and I think this crosses that line. (As does "unless" and "until" quite often.)

In reply to Re (tilly) 1: Implication operator by tilly
in thread Implication operator by kaatunut

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.