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From: Ben Bacarisse <ben.usenet@bsb.me.uk>
Newsgroups: comp.lang.javascript
Subject: Re: passing a set of numbers to a function
Date: Fri, 05 Feb 2016 14:34:49 +0000
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Scott Sauyet <scott.sauyet@gmail.com> writes:
<snip>
> I wasn't thinking about practical implementation at all.
<snip>
> But they're an interesting exercise regardless.

I think there are practical uses.  I've used this method on a web site
(hey, topical!) that had complex match expressions in a search function.
To implement something like ("a" | "b") & ~"c" you parse the expression
and build a matching functions as you go.  Given something like

  function any(x) { return set(s => s.includes(x)); }

the result of parsing ("a" | "b") & ~"c" is

  const r = (any("a").union(any("b")).intersection(any("c").complement()));

and you simply test r.contains("whatever") to do the match.

-- 
Ben.