Exercism v3 launches on Sept 1st 2021. Learn more! ๐Ÿš€๐Ÿš€๐Ÿš€
Avatar of NickSeagull

NickSeagull's solution

to Clock in the Raku Track

Published at Jul 26 2020 · 0 comments
Test suite


This exercise has changed since this solution was written.

Implement a clock that handles times without dates.

You should be able to add and subtract minutes to it.

Two clocks that represent the same time should be equal to each other.


Remember to check out the Raku documentation and resources pages for information, tips, and examples if you get stuck.

Running the tests

There is a test suite and module included with the exercise. The test suite (a file with the extension .t6) will attempt to run routines from the module (a file with the extension .pm6). Add/modify routines in the module so that the tests will pass! You can view the test data by executing the command perl6 --doc *.t6 (* being the name of the test suite), and run the test suite for the exercise by executing the command prove6 . in the exercise directory.


Pairing session with Erin Drummond https://twitter.com/ebdrummond

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.

unit class Clock;

my constant minutes-in-hour = 60;
my constant hours-in-day = 24;

has $.hour;
has $.minute;

submethod TWEAK() {
  $!hour += $!minute div minutes-in-hour;
  $!minute = $!minute mod minutes-in-hour;
  $!hour = $!hour mod hours-in-day;

method time {
  my $h = $!hour >= 10 ?? $!hour !! "0$!hour";
  my $m = $!minute >= 10 ?? $!minute !! "0$!minute";

method add-minutes (Int $amount --> Clock) {
  $!minute += $amount;

method subtract-minutes (Int $amount --> Clock) {
  $!minute -= $amount;

Community comments

Find this solution interesting? Ask the author a question to learn more.

What can you learn from this solution?

A huge amount can be learned from reading other peopleโ€™s code. This is why we wanted to give exercism users the option of making their solutions public.

Here are some questions to help you reflect on this solution and learn the most from it.

  • What compromises have been made?
  • Are there new concepts here that you could read more about to improve your understanding?