Beefy Boxes and Bandwidth Generously Provided by pair Networks
Just another Perl shrine

Comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
Upon writing $a % 0 I am told that 0 is an illegal modulus.

However, according to "Concrete Mathematics: A Foundation for Computer Science", by Graham, Knuth (yes, that Knuth) and Patashnik 2nd ed. (page 82)
x mod y is defined as x - y{x/y} (where {} is floor) for y!=0, and x mod 0 is defined to be x.
This definition is justified; it preserves the property that x mod y always differs from x by a multiple of y, and makes sense if you think of it this way: x mod y means "map y to 0", so if y already is 0, then there is nothing to do, and x mod 0 should be congruent to x.

Yes, I know that division by 0 is a Bad Thing, but technically we are not dividing, we are defining the mod operator.

So this is more of a rant than a question, but it annoys me to lose functionality from one of my favourite operators in such an amusing language as Perl.

In reply to 0 illegal modulus? by nella

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, 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, 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.
  • Log In?

    What's my password?
    Create A New User
    and all is quiet...

    How do I use this? | Other CB clients
    Other Users?
    Others making s'mores by the fire in the courtyard of the Monastery: (6)
    As of 2018-06-21 10:54 GMT
    Find Nodes?
      Voting Booth?
      Should cpanminus be part of the standard Perl release?

      Results (118 votes). Check out past polls.