28 lines
721 B
Standard ML
28 lines
721 B
Standard ML
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use "operators.sml";
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use "list.sml";
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fun first str = String.sub (str, 0)
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val only_capitals = filter (first >> Char.isUpper)
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val size = String.size
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fun choose f a b = if f a b then a else b
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fun biggest a b = size a > size b
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fun bigger_or_equal a b = size a >= size b
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val longest_string1 = foldl (choose biggest) ""
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val longest_string2 = foldl (choose bigger_or_equal) ""
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fun longest_string_helper f =
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let
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val longest_string3 = longest_string1
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val longest_string4 = longest_string2
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in
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if f (0, 0)
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then longest_string4
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else longest_string3
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end
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val longest_capitalized = only_capitals >> longest_string2
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val rev_string = String.explode >> List.rev >> String.implode
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