LÖVE

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function intersect(x1, y1, x2, y2, x3, y3, x4, y4)
    local x21, x43 = x2 - x1, x4 - x3
    local y21, y43 = y2 - y1, y4 - y3
    local d = x21 * y43 - y21 * x43
    if d == 0 then return false end
    local xy34 = x3 * y4 - y3 * x4
    local xy12 = x1 * y2 - y1 * x2
    local a = xy34 * x21 - xy12 * x43
    local b = xy34 * y21 - xy12 * y43
    return a / d, b / d
end

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function intersect(x1, y1, x2, y2, x3, y3, x4, y4)
  local dx1, dy1 = x2 - x1, y2 - y1
  local dx2, dy2 = x4 - x3, y4 - y3
  local dx3, dy3 = x1 - x3, y1 - y3
  local d = dx1*dy2 - dy1*dx2
  if d == 0 then
    return -- collinear
  end
  local t1 = (dx2*dy3 - dy2*dx3)/d
  local t2 = (dx1*dy3 - dy1*dx3)/d
  return x1 + t1*dx1, y1 + t1*dy1, t1, t2
end

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function intersectSegment(x1, y1, x2, y2, x3, y3, x4, y4)
  local dx1, dy1 = x2 - x1, y2 - y1
  local dx2, dy2 = x4 - x3, y4 - y3
  local dx3, dy3 = x1 - x3, y1 - y3
  local d = dx1*dy2 - dy1*dx2
  if d == 0 then
    return -- collinear
  end
  local t1 = (dx2*dy3 - dy2*dx3)/d
  if (t1 < 0) or (t1 > 1) then
    return -- non-intersecting segment 
  end
  local t2 = (dx1*dy3 - dy1*dx3)/d
  if (t2 < 0) or (t2 > 1) then
    return -- non-intersecting segment
  end
  return x1 + t1*dx1, y1 + t1*dy1, t1, t2
end

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local function new(c, ...)
    local inst, ctor = setmetatable({}, c), c.init
    if ctor then ctor(inst, ...) end
    return inst
end

local class = function (super)
    local class = setmetatable({ super = super }, { __index = super, __call = new })
    class.__index = class
    return class
end

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local myClass = class(mySuperClass)

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local instance = new(myClass, ...)

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local instance = myClass(...)

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function chance(p)
    return math.random() < p
end

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if chance(0.5) then
    print('heads')
else
    print('tails')
end

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-- lock global table

setmetatable(_G, {
    __index = function () error('referenced an undefined variable', 2) end,
    __newindex = function () error('new global variables disabled', 2) end
})

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function angularDistance(a, b)
    return math.abs(math.atan2(math.sin(a - b), math.cos(a - b)))
end

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function angleDifference(t1, t2)
   return (t1 - t2 + math.pi) % (math.pi * 2) - math.pi
end