小数点数型→整数型キャスト

my $i = $r.truncate;
my $i = $r.Int;

のように使うっぽい。

my $i = Int($r);  # error!

は、Rakudo star 2010.08時点では未実装。

truncate: Returns the closest integer to $x whose absolute value is not greater than the absolute value of $x. (In other words, just chuck any fractional part.) This is the default rounding function used by implicit integer conversions.

You may also truncate using explicit integer casts, either Int() for an arbitrarily large integers, or int() for native integers.

http://perlcabal.org/syn/S32/Numeric.html