The LayerIndex type is used to specify which conductor layer in the board stackup that a particular statement or property affects.


defstruct LayerIndex :

defn LayerIndex (index:Int, side:Side = Top) -> LayerIndex:

The LayerIndex type expects two arguments:

  1. index - If we consider the conductor layers in board stackup an zero-indexed array, the index is the offset into the array from either the Top or the Bottom.
  2. side - This parameter determines whether the index applies from the Top going down, or from the Bottom going up.

Symmetry of Top and Bottom Indices

The Bottom side indices can be considered a reverse indexing scheme.

Layer Indices

Notice that there is a way to index every layer in the stackup in either direction.

Shortcuts based on Side

In some applications of the LayerIndex type, you will often see the type LayerIndex|Side used. This means that the user can pass either a LayerIndex or a Side parameter in the form of Top or Bottom enumerated values.

These Side values are a shortcut for:

  1. Top => LayerIndex(0, Top)
  2. Bottom => LayerIndex(0, Bottom)


Currently the plus and minus operators are defined for the LayerIndex and Side types. This provides a short cut for indexing:

val inner-1 = Top + 1
println("Inner 1: %_" % [inner-1])

val inner-N-1 = Bottom - 1
println("Inner N-1: %_" % [inner-N-1])

val inner-skip = inner-1 + 2
println("Inner Skip: %_" % [inner-skip])

When run this will generate:

Inner 1: LayerIndex(1)
Inner N-1: LayerIndex(1, Bottom)
Inner Skip: LayerIndex(3)