42 lines
1.1 KiB
Standard ML
42 lines
1.1 KiB
Standard ML
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(* TAKL -- The TAKeuchi function using lists as counters. *)
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fun list_n n =
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let fun loop (n, a) =
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if n = 0
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then a
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else loop (n-1, n::a)
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in loop (n, [])
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end
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val l18 = list_n 18
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val l12 = list_n 12
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val l6 = list_n 6
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(* Part of the fun of this benchmark is seeing how well the compiler
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can understand this ridiculous code, which dates back to the original
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Common Lisp. So it probably isn't a good idea to improve upon it. *)
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fun shorterp (x, y) =
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not (y = [])
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andalso (x = [] orelse shorterp (tl x, tl y))
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(* But SML/NJ runs this benchmark about 15 times as fast when the
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code above is rewritten as follows. So I did it. Pooh. *)
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fun shorterp (_, []) = false
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| shorterp ([], _) = true
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| shorterp (_::x, _::y) = shorterp (x, y)
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fun mas (x, y, z) =
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if not (shorterp (y, x))
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then z
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else mas (mas (tl x, y, z),
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mas (tl y, z, x),
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mas (tl z, x, y))
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fun takl_benchmark (n) =
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run_benchmark ("takl", n, fn () => mas (l18, l12, l6),
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fn (x) => length(x) = 7)
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fun main () = takl_benchmark (takl_iters)
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