Moonlight wrote: My question, how to extract the mirror operation value ??
You have SYMB_MIRRORED and SYMB_ROTANGLE.
If the rotation angle is 180° (and symb_mirrored is set of course) you can tell it was mirrored a long the x-axis. If no rotation angle is set the mirror axis was the y-axis.
But I don't think you can tell what the very last operation was, since there is no way to compare between states in GDL.