Course of Raku / Objects, I/O, and exceptions / Exceptions / Custom exceptions / Exercises / Two exception types

Solution: Two exception types

Here is a possible solution to the task.

Code

class TooSmall is Exception {
    method message { 'too small' }
}

class TooBig is Exception {
    method message { 'too big' }
}

for TooSmall, TooBig -> $type {
    {
        $type.new.throw;

        CATCH {
            when TooSmall { say 'small' }
            when TooBig   { say 'big' }
        }
    }
}

🦋 You can find the source code in the file two-exceptions.raku.

Output

small
big

Comments

1. The loop throws a TooSmall on the first pass and a TooBig on the second, each inside its own block with its own CATCH.

2. The CATCH phaser has a when branch for each exception type. On each pass, only the branch matching the thrown type runs — so the first pass prints small and the second prints big. This is how a single set of handlers reacts differently to different kinds of error.

Course navigation

← Two exception types   |   Quiz — Custom exceptions →