###
 Returns the real part of complex z

  z    real(z)
  -    -------

  a + i b    a

  exp(i a)  cos(a)
###



Eval_real = ->
  push(cadr(p1))
  Eval()
  real()

real = ->
  save()
  rect()
  p1 = pop()
  push(p1)
  push(p1)
  conjugate()
  add()
  push_integer(2)
  divide()
  restore()