A Lisp expression that you can evaluate is called a form. Evaluating a form always produces a result, which is a Lisp object. In the examples in this manual, this is indicated with ‘
(car '(1 2))
You can read this as “
(car '(1 2)) evaluates to 1".
When a form is a macro call, it expands into a new form for Lisp to evaluate. We show the result of the expansion with ‘
→’. We may or may not show the result of the evaluation of the expanded form.
(third '(a b c))
→ (car (cdr (cdr '(a b c))))
To help describe one form, we sometimes show another form that produces identical results. The exact equivalence of two forms is indicated with ‘
(make-sparse-keymap) ≡ (list 'keymap)