Perl 6 Deep Dive

Using labels

Let's consider an example with nested loops:

for 1..5 -> $x {   for 1..5 -> $y {       say "$x * $y = ", $x * $y;   }}

This program prints the product table for the numbers from 1 to 5. What if, at some point, we want to skip the rest of the table for the given $x, and continue with the next value of $x? The direct usage of next inside the loop for $y will only affect the inner loop. To make sure that the next statement is modifying the execution of the outer loop, use X_LOOP:

X_LOOP: for 1..5 -> $x {   for 1..5 -> $y {       next X_LOOP if $y == $x;       say "$x $y = ", $x $y;   }}

The label here is a capitalized identifier X_LOOP followed by the colon. It is mentioned in the next statement, so the compiler understands that the next iteration should ...