How To Compute Fraction

Fract.lua

-- A function that return a fraction computed from a floating number.

function int(arg)
local e,d = math.modf(arg)
return e
end

function dec2fr(decimal,acc)
local acc = acc
if not acc then acc =  1E-4 end
local sign,z,predenum,sc,_,num,denum
	if (decimal<0) then sign = -1 else sign = 1 end
decimal=math.abs(decimal)
	if decimal == int(decimal)  then
	num = decimal*sign
	denum = 1
	end
	if decimal < 1E-19 then
	num = sign
	denum = 9999999999999999999;
	end
	if decimal > 1E+19 then
	num = 9999999999999999999*sign
	denum = 1
	end
z = decimal
predenum = 0
denum= 1
	repeat
	z = 1/(z-int(z))
	sc = denum
	denum = denum*int(z)+predenum
	predenum = sc
	num = int(decimal*denum)
	until (math.abs(decimal-(num/denum))<acc) or (z==int(z))
	num = sign*num
	return num,denum
end


print(dec2fr(math.pi,1E10))