Hardware Design: SIE

Hardware Design: SIE Git Source Tree

1	-- function closures are powerful
2
3	-- traditional fixed-point operator from functional programming
4	Y = function (g)
5	local a = function (f) return f(f) end
6	return a(function (f)
7	return g(function (x)
8	local c=f(f)
9	return c(x)
10	end)
11	end)
12	end
13
14
15	-- factorial without recursion
16	F = function (f)
17	return function (n)
18	if n == 0 then return 1
19	else return n*f(n-1) end
20	end
21	end
22
23	factorial = Y(F) -- factorial is the fixed point of F
24
25	-- now test it
26	function test(x)
27	io.write(x,"! = ",factorial(x),"\n")
28	end
29
30	for n=0,16 do
31	test(n)
32	end
33

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