Example

> if (1+2 <= 4)
  {
  a = 6
  else
  a = -6
  }
 a =
        6
> if (1+2 < 3)
  {
  a = 6
  else
  a = -6
  }
 a =
       -6
> if( class(a) == "num")
  {
  b = tan(a)
  c = 2+3-4
  else
  a = 0
  }
 b =
    0.291
 c =
        1
> if ( 0 )
  {
  b = " false "
  else if (c < (d = 2)) 
  {
  e = -d
  else
  e = d
  }}
 e =
       -2