Parameters

Cells become far more useful with parameters:

cell Pad {
    param {
        side size = 80um
    }
    layer metal {
        shape rect with side, side as body
        place body at self.origin
    }
}

Each parameter has a name, a type and usually a default value. The types are those of the values: integer, number, size, angle, string, bool, point, and lists such as [size]. A parameter without a default must be given every time the cell is placed.

Inside the cell a parameter is used by its name. When placing the cell, with sets parameters by name:

place Pad with side = 60um at (0, 0)

Each combination of parameter values becomes a cell of its own in the output. With all the default values it keeps the cell's name (Pad); other values give it a name with a hash (Pad$1f3a9c02).