Two simple things you can do (also in Perl 5):

You can get rid of the temporary $t by using list assignment: 

    while $b != 0 {
        ($b, $a) = ($a % $b, $b);
    }

[download]

Or you can resort to recursion, ignoring your boundaries to the golf court: 

sub gcd ($a, $b) {
    return $a if !$b;
    gcd($b, $a % $b);
}

say gcd(24, 42);

[download]

For none of these I can see something where Perl 6 really plays its strengths.

So maybe something completely else? This might work, but since nobody implements infix:<...> yet, I couldn't test it: 

sub gcd ($a, $b) {
    ($a, $b ... { $^x % $^y || () })[*-1]
}

[download]

For example for gcd(42, 24) it would produce the list 42, 24, 18, 6. During the next call to the block it the $^x % $^y returns 0, and the block the empty list, ending the creation of the list. The last element is the gcd.

In reply to Re: Euclidean algorithm Golf in Perl 6 by moritz
in thread Euclidean algorithm Golf in Perl 6 by John M. Dlugosz

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.