Tip Calculator

tip-calculator.p6

use v6;

subset DollarAmount of Cool where * ~~ ^<[0 .. 9\.]>+$;
subset Percentage of DollarAmount where * > 1;

my $bill-amount; 
my $tax-percentage; 

repeat {
    $bill-amount = prompt "What is the bill amount? "
} until DollarAmount($bill-amount) !~~ Failure;

repeat {
    $tax-percentage = prompt "What is the tip percentage? "
} until Percentage($tax-percentage) !~~ Failure;

my $tip-amount = ($bill-amount * ($tax-percentage / 100)).round: 0.01;

say "The tip amount is \$$tip-amount.";
say "The total amount is \$", $bill-amount + $tip-amount, ".";

This works:

subset DollarAmount of Cool where /^ <[0 .. 9\.]>+ $/;
subset Percentage of Numeric where * > 1;

my $bill-amount; 
my $tax-percentage; 

repeat {
    $bill-amount = prompt "What is the bill amount? "
} until $bill-amount ~~ DollarAmount;

repeat {
    $tax-percentage = prompt "What is the tip percentage? "
} until $tax-percentage ~~ Percentage;

my $tip-amount = ($bill-amount * ($tax-percentage / 100)).round: 0.01;

say "The tip amount is \$$tip-amount.";
say "The total amount is \$", $bill-amount + $tip-amount, ".";