The Roots of Lisp

In “The Roots of Lisp” we see a very in depth and specific description of how the lisp language came to be, explaining how John McCarthy created a “list processing” language that used structures called lists for both the data and the code of a program. This way of processing data is not just something that stayed in the past but something that paves the way programming is going at the moment. With better and more powerful computers, we can see why this programming structure is becoming more common. The article continues giving us the seven primitive operators of Lisp.

The seven primitive operators are quote, atom, eq, car, cdr, cons, and cond, these form the base of Lisp. “quote” returning whatever arguments are given after it, “atom” returning “t” if the argument is an atom or an empty list and returning () otherwise; in Lisp the “t” represents truth and () represents false, “eq” returns “t” if the values of the arguments given are equal and () otherwise, “car” returns the first element of the given list where it is implied that the argument is a list, “cdr” returns the elements after the first in the given argument list. Cons returns a list with the first argument given followed by the elements of the second argument given which should be a list, and “cond” is evaluated where it is arguments are also evaluated until one of them returns “t” and returns the value after the correct argument.

As we can see, Lisp contains elements we are familiar with from other programing languages and that would be expected to have, yet the way these arguments are evaluated, gives Lisp a very different use as to what we are used to from other languages and provide us with a different way of processing data