Boolean Commands with 3 or More Layers

You'll need to use a temporary layer, sorry. That's not too onerous though - you can use the temporary layer and keep deleting it as you go along.

Andrew.

Thanks for the quick reply.

Perhaps my procedure for creating the temporary layer is horrifically complicated?

Right now I am going into my tech file manager and creating a new layer and assigning it all the regular assortment of goodies.  Then referencing it in the code.

Is there a better way to do this?

Usually people just use one of the existing standard internal layers (e.g. y0, y1, y2 etc) to do this kind of thing. No need to invent yet another layer for your internal working, so that avoids you having to define anything new. Then you can easily write a function that extends the current functions to a variable number of arguments and breaks it down into steps which do:

listOfShapes=dbLayerAnd("y0" lay1Shapes lay2Shapes)
newListOfShapes=dbLayerAnd("y0" listOfShapes lay3Shapes)
foreach(shape listOfShapes dbDeleteObject(shape))
listOfShapes=newListOfShapes
newListOfShapes=dbLayerAnd("outLayer" listOfShapes lay4Shapes)
foreach(shape listOfShapes dbDeleteObject(shape))
newListOfShapes ; return value

And you could make that inner stuff a loop - so you could handle arbitrarily many layers.  Here's one I just threw together with very little thought:

 /* abLayerOps.il

Author     A.D.Beckett
Group      Custom IC (UK), Cadence Design Systems Ltd.
Language   SKILL
Date       Feb 27, 2012
Modified   
By         

abLayerOps('dbLayerAnd cvId "Metal4" m1Shapes m2Shapes)
abLayerOps('dbLayerAnd cvId "Metal4" m1Shapes m2Shapes m3Shapes)
abLayerOps('dbLayerAnd cvId "Metal4" m1Shapes m2Shapes m3Shapes m5Shapes)

***************************************************

*/

abLayerOps.tmpLayer="y0"
procedure(abLayerOps(layerFunc cvId outLayer @rest inShapeLists)
    let((outShapeList lastShapes toLayer)
    unless(cdr(inShapeLists)
        error("abLayerOps: requires at least two lists of shapes)")
    )
    lastShapes=car(inShapeLists)
    foreach(maplist remShapeList cdr(inShapeLists)
        toLayer=if(cdr(remShapeList) abLayerOps.tmpLayer outLayer)
        outShapeList=funcall(layerFunc cvId toLayer lastShapes car(remShapeList))
        unless(eq(lastShapes car(inShapeLists))
        foreach(shape lastShapes dbDeleteObject(shape))
        )
        lastShapes=outShapeList
    )
    lastShapes
    )
)

Regards,

Andrew.