Example of allowing free text entry of significant tokens in Interface Builder (for an @IBDesignable view) using a bitmask.

gistfile1.swift

    // Unfortunately, this has to be a string right now as IBInspectable enums are not supported at the moment.
    @IBInspectable var alignmentToParentName:String = "top right"
    {
        didSet
        {
            var name = (alignmentToParentName.lowercaseString as NSString)
            let top = 0b00, bottom = 0b10, right = 0b00, left = 0b01
            var bitmask = 0b0
            
            // The default, even if garbage is entered in Interface Builder, is top right.
            bitmask |= name.containsString("bottom") ? bottom : top
            bitmask |= name.containsString("left") ? left : right

            alignmentToParent = alignments[bitmask]
            
            println("Alignment to parent is \(alignmentNames[bitmask]).")
        }
    }
    
    enum Alignment { case topRight; case topLeft; case bottomRight; case bottomLeft; }
    let alignments = [Alignment.topRight, Alignment.topLeft, Alignment.bottomRight, Alignment.bottomLeft]
    let alignmentNames = ["top right", "top left", "bottom right", "bottom left"]

So, basically, this would work regardless of whether you entered bottomLeft, bottom left, bottom-left, etc. in Interface Builder’s Attribute Inspector.

(Note: this was the first iteration for a feature. This parameter is actually unnecessary as the placement of the item in design view — relative to parent — should automatically determine alignment.)

Note: updated so that the default values are zeros and non-default values are ones (as per https://twitter.com/Bob_at_BH/status/622380717784367105 by Bob Koon). Also altered the order so that they match the language order in which we talk about the problem domain — in this case, the alignment of an unread count badge to its parent view: top-right, top-left, bottom-right, bottom-left.