(lispref.info)Evaluation Notation

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Evaluation Notation

   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))
          => 1

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 actual result of the evaluation of the expanded form.

     (third '(a b c))
          ==> (car (cdr (cdr '(a b c))))
          => c

   Sometimes to help describe one form we show another form which
produces identical results.  The exact equivalence of two forms is
indicated with `=='.

     (make-sparse-keymap) == (list 'keymap)

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