Set::Builder synopsis

set-builder_synopsis.pl

use Set::Builder qw(Set Var for_all);

# set constructor, roster style:
my $set = Set { 0..9 };

# element variable constructor:
my ($x, $y) = (Var) x 2;

# subset consisting of the numbers 0 and 1
my $subset1 = Set { $x ~~ $set | $x ~~ Set { 0..1 } };

# subset also consisting of the numbers 0 and 1:
my $subset2 = Set { $x ~~ $set | $x ~~ Set { -1..1 } };

# subset consisting of the numbers 0, 1, and 10:
my $subset4 = Set { $subset1 + Set { 10 } };

# subset consisting of the number 9:
my $subset5 = Set { $x ~~ $set | for_all $y ~~ $set, $x >= $y };

# empty subset:
my $subset6 = Set { $x ~~ $set | for_all $y ~~ $set, $x != $y };