RosettaCodeData/Task/First-class-functions/Lingo/first-class-functions-2.lingo

on square (x)
  return x*x
end

on asin (x)
  res = atan(sqrt(x*x/(1-x*x)))
  if x<0 then res = -res
  return res
end

on acos (x)
  return PI/2 - asin(x)
end