Course of Raku / Functional, concurrent, reactive, and web programming / Functional programming / Iterators / Exercises / Sum with pull-one

Solution: Sum with pull-one

Here is a possible solution to the task.

Code

my $it = (3, 7, 5).iterator;
my $sum = 0;

loop {
    my $v := $it.pull-one;
    last if $v =:= IterationEnd;
    $sum += $v;
}

say $sum;

🦋 You can find the source code in the file sum-with-pull-one.raku.

Output

15

Comments

1. .iterator gives the pull-based view of the list, and each pull-one returns the next number.

2. The value is bound with :=, not assigned, so $v =:= IterationEnd can spot the end correctly — an assigned = would compare the container instead of the value. The loop adds 3, 7, and 5, then meets IterationEnd and stops, leaving 15.

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