Power set
editable example
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ghul
use IO.Std.write_line
use Collections.Iterable
use Collections.List
use Collections.LIST
use Ghul.Pipes
power_set[T](values: List[T]) -> LIST[LIST[T]] is
if values.count == 0 then
let empty: LIST[LIST[T]] = _()
empty.add(LIST[T]())
return empty
fi
let first = values[0]
let result: LIST[LIST[T]] = _()
for subset in power_set(values |> skip(1) |> collect()) do
let with_first: LIST[T] = _()
with_first.add(first)
with_first.add_range(subset)
result.add(subset)
result.add(with_first)
od
return result
si
braced[T](values: Iterable[T]) -> string => "{{{values |> join(", ")}}}"
show[T](sets: LIST[LIST[T]]) -> string =>
braced(sets |> map(subset => braced(subset)))
write_line(show(power_set(LIST[int]())))
write_line(show(power_set([1, 2, 3] |> collect())))
write_line(show(power_set(["a", "b"] |> collect())))