Course of Raku / Functional, concurrent, reactive, and web programming / Reactive programming / Live and on-demand supplies / Exercises / Two taps

Solution: Two taps

Here is a possible solution to the task.

Code

my $s = Supply.from-list(1, 2, 3);

my @doubled;
my @tripled;
$s.map(* * 2).tap(-> $v { @doubled.push($v) });
$s.map(* * 3).tap(-> $v { @tripled.push($v) });

say @doubled;
say @tripled;

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

Output

[2 4 6]
[3 6 9]

Comments

1. Supply.from-list is on-demand, so it replays its full sequence for each tap, independently.

2. That lets the two taps run different pipelines over the same source: one doubles, one triples. Each sees all of 1, 2, 3, so the results are [2 4 6] and [3 6 9].

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