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app "higher-order"
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packages { pf: "https://github.com/roc-lang/basic-cli/releases/download/0.7.1/Icc3xJoIixF3hCcfXrDwLCu4wQHtNdPyoJkEbkgIElA.tar.br" }
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imports [pf.Stdout, pf.Task]
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provides [main] to pf
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main : Task.Task {} I32
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main =
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fn1 = bind Num.sub 3
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fn2 = bindL Num.sub 3
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fn3 = compose fn2 fn1
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results =
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[fn1 2, fn2 2, fn3 2]
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|> List.map Num.toStr
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|> List.mapWithIndex \e, idx -> "fn$(Num.toStr idx) -> $(e)"
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|> Str.joinWith "\n"
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Stdout.line "$(results)"
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bind : (a, b -> c), a -> (b -> c)
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bind = \fn, a ->
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\b -> fn a b
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bindL : (a, b -> c), b -> (a -> c)
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bindL = \fn, b ->
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\a -> fn a b
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compose : (a -> b), (b -> c) -> (a -> c)
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compose = \fn1, fn2 ->
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\a -> fn1 a |> fn2
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