Turtlescript Goto Command

h = vector.new(gps.locate(5)) or vector.new(0,0,0)
a = {...}
k=tonumber
d = vector.new(k(a[1]),k(a[2]),k(a[3]))

if a[4]=="r" then
    t = d
else
    t=d-h
end

m=math.abs
f=m(t.x)+m(t.y)+m(t.z)

b=turtle
e=b.forward
n=b.turnRight
o=b.turnLeft
p=b.dig
q=b.attack
r=b.up
s=b.down
u=b.detect

if b.getFuelLevel() < f then
  for i=1,16 do
      b.select(i)
      b.refuel()
  end
end

function w(l,h,d)
    for i=l,h do
        if u() then
            if not q() then
                p()
            end
        end
        d()
    end
end

function v()
    n()
    n()
end

if d.x>h.x then
    w(h.x,d.x,e)
else
    v()
    w(d.x,h.x,e)
    v()
end

if d.y>h.y then
    n()
    w(h.y,d.y,e)
    o()
else
    o()
    w(d.y,h.y,e)
    n()
end

if d.z>h.z then
    w(h.z,d.z,r)
else
    w(d.z,h.z,s)
end