This is a compressed idiomatic form, quite comprehensible even if not grammatical in construction - it is not a sentence, having no main verb. We look at this next. The amount payable on a purchase is the purchase-price plus the computed tax. This sequence is isolated, by being on the right-hand side of the assignment. Then to test whether a number is a whole number or not, we can ask whether it is equal to its floor.
L is given by the sum of L divided by the number of items in L .
An isolated sequence of three verbs is called a fork. For more about trains, see Chapter 09 . Let us now try a longer example which puts together several of the ideas we saw above. The idea is to define a verb to produce a simple display of a given list of numbers, showing for each number what it is as a percentage of the total. Let me begin by showing you a complete program for this example, so you can see clearly where we are going.