1. ## lib/Monad/Writer.rakumod
2. use Monad;
4. unit class Monad::Writer is Monad;
6. has $.value;
7. has $.logs = '';
9. method unwrap {
10. $.value;
11. }
13. method logs {
14. $.logs;
15. }
17. method unit($value --> Monad::Writer) {
18. self.new(value => $value);
19. }
21. ## t/06_writer.t
22. use Test;
23. use lib 'lib';
24. use Monad;
25. use Monad::Writer;
27. plan 10;
29. # unit
30. my $w1 = Monad::Writer.unit(42);
31. isa-ok $w1, Monad::Writer, 'unit() returns a Monad::Writer';
32. is $w1.unwrap, 42, 'unwrap returns correct value';
33. is $w1.logs, '', 'initial log is empty';