Lesson goal: Converting units

Previous: Simulating digital circuits (3) | Home | Next: Reasoning about points and lines (1)

You likely know about units conversion, as in "convert 4 feet into centimeters." This is a lot like the routing lesson, only instead of going from city A to B, we want to get from unit A to unit B.

To begin, the "data" we'll need for this will be conversion facts, like the fact that there's 12 inches in 1 foot, or 100 centimeters in 1 meter. Our plan is to simply give these facts to Prolog, then be able to ask it something like convert(foot,centimeter). With this, it should show us how to convert for example 4 ft into cm.

After the facts, the core conversion clause is called convert(To,From,Steps), which will work to show us how to convert a quantity in units of To into a quantity of From, putting the textual steps into Steps.