How does Array.Extra.all short circuit?

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I think the accumulator soFar becomes False and then the expression soFar && isOkay element never evaluates the isOkay element bit sionce && short circuits. But it will still loop over the entire array, all the way to the end.

You could experiement by changing the all code to:

all : (element -> Bool) -> (Array element -> Bool)
all isOkay =
    Array.foldl
        (\element soFar -> isOkay element && soFar)
        True

Then running that through your Ellie.