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(emacs-lisp-intro.info)Sample let Expression

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Sample `let' Expression
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   The following expression creates and gives initial values to the two
variables `zebra' and `tiger'.  The body of the `let' expression is a
list which calls the `message' function.

     (let ((zebra 'stripes)
           (tiger 'fierce))
       (message "One kind of animal has %s and another is %s."
                zebra tiger))

   Here, the varlist is `((zebra 'stripes) (tiger 'fierce))'.

   The two variables are `zebra' and `tiger'.  Each variable is the
first element of a two-element list and each value is the second
element of its two-element list.  In the varlist, Emacs binds the
variable `zebra' to the value `stripes', and binds the variable `tiger'
to the value `fierce'.  In this example, both values are symbols
preceded by a quote.  The values could just as well have been another
list or a string.  The body of the `let' follows after the list holding
the variables.  In this example, the body is a list that uses the
`message' function to print a string in the echo area.

   You may evaluate the example in the usual fashion, by placing the
cursor after the last parenthesis and typing `C-x C-e'.  When you do
this, the following will appear in the echo area:

     "One kind of animal has stripes and another is fierce."

   As we have seen before, the `message' function prints its first
argument, except for `%s'.  In this example, the value of the variable
`zebra' is printed at the location of the first `%s' and the value of
the variable `tiger' is printed at the location of the second `%s'.