Idiom # 119: Deduplicate list

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Code

# preserving order x := for r list<string> := nil, if (s.has e) r else cons e, r s := psSet<string>, s.add e e in x else r.reverse # not preserving order x := for s := psSet<string>, s.add e e in x else s.asArray

Running Example

ex119 is # preserving order x := [ "b", "a", "b", "c" ] x := for r list<string> := nil, if (s.has e) r else cons e, r s := psSet<string>, s.add e e in x else r.reverse say x # not preserving order x := [ "b", "a", "b", "c" ] x := for s := psSet<string>, s.add e e in x else s.asArray say x