I don't necessarily agree that the "spirit of the law" is quite so nebulous. If a law is like a computer program, the "spirit of the law" is the program that you are trying to write, and the "letter of the law" is the program that you have written. If you've written a calculator and dividing 2 by 2 produces negative infinity, nobody will argue that this is a bug and not what the programmer intended.

The spirit of the law is the programmer's intention, the design document, the thing the customer wants you...to...build.....

Right, okay, I've changed my mind. That's nebulous.