So, I'm trying to work through some of the PASCAL90 source code for
tetrahedrons, and I started with the first one:

I'm assuming "R8" is a real 8-bit number, or something like that.

!! R8_SWAP swaps two R8's.
!
!  Licensing:
!
!    This code is distributed under the GNU LGPL license.
!
!  Modified:
!
!    22 December 2000
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input/output, real ( kind = 8 ) X, Y.  On output, the values of X and
!    Y have been interchanged.
!
  implicit none

  real ( kind = 8 ) x
  real ( kind = 8 ) y
  real ( kind = 8 ) z

  z = x
  x = y
  y = z

  return
end

Which in SDL translates (roughly) to:

#macro SwapXY (X, Y)
 // Input/output: X, Y
 // On output, the values of X and Y have been interchanged.
 #local Z = X; // Z is a placeholder variable
 #local X = Y;
 #local Y = Z;
#end

My question is, does a mechanism exist by which the true identities of the
variable names passed to the macro can be accessed?
Such that if I do:
#macro SwapXY (OneVariable, Another)

it will actually redefine THOSE variables?
(because until the macro is instantiated, X and Y are not yet defined (in the
macro microcosm) and are throw-away temporary variable names.  Using #declare
would only create new variables or redefine any existing global-level X and Y.)

I'm guessing not, and that I'd best do a tuple-style assignment and have the
macro "return" those two values on the last line...

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