Arc Forum | let [... _ ...] mean (fn _ (... _ ...))example usage: (reduce [- (/ _.1 (* 2

Arc Forum

1 point by rincewind 5888 days ago | link | parent

let [... _ ...] mean (fn _ (... _ ...))

example usage:

  (reduce [-  (/ _.1 (* 2 _.0))] mylist)

1 point by absz 5888 days ago | link

Unfortunately, this is then deoptimized for the most common one-argument case, where you have to write [... _.0 ...]. We could have [...] expand to (fn __ (let _ (car _) ...)), so that you would have

  (reduce [- (/ __.1 (* 2 __.0))] mylist)

but still have

  (map [+ _ (* _ _)] myotherlist)

. I still prefer the _1, _2, ... syntax, though---unsurprisingly, as I contributed that implementation (though not the idea) :)

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1 point by shader 5888 days ago | link

Actually, I do think the _1, _2 .. syntax makes the most sense, if you aren't wanting to name parameters. Though maybe (as was mentioned above) in some cases, the first three should be a b c, or x y z? I don't know how you would set that up to work well with what already exists though.

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