What do "if" and "undef" mean? What's the relative precedence of "unless", "or" and "if"? If your snippet is equivalent to

if (not B) {
   A 
} else {
   if (E and F) {   
      C and D
   } else {         
      undef
   }
}

[download]

it can be written as

(not B and A)
or
(B and (
   ((E and F) and (C and D))
   or
   (not (E and F) and undef)
))

[download]

and simplified (through logic arithmetic) to

(not B and A) or (B and E and F and C and D)

[download]

Notes:

For convertion to single expressions:
if (A) { B } else { C } === (A and B) or (not A and C)

For simplification:
X and undef === undef
X or undef  === X

[download]

In reply to Re: Complex conditional statements by ikegami
in thread Complex conditional statements by bofh_of_oz

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.