###
 Returns the coefficient of the imaginary part of complex z

  z    imag(z)
  -    -------

  a + i b    b

  exp(i a)  sin(a)
###

DEBUG_IMAG = false

Eval_imag = ->
  push(cadr(p1))
  Eval()
  imag()

imag = ->
  save()
  rect()
  p1 = pop()

  if DEBUG_IMAG then console.log "IMAGE of " + p1

  push(p1)
  push(p1)
  conjugate()
  if DEBUG_IMAG then console.log " image: conjugate result: " + stack[tos-1]

  subtract()
  push_integer(2)
  divide()
  if DEBUG_IMAG then console.log " image: 1st divide result: " + stack[tos-1]
  push(imaginaryunit)
  divide()
  if DEBUG_IMAG then console.log " image: 2nd divide result: " + stack[tos-1]
  restore()