Re: Problem understanding set-register syntax

[Kevin Rodgers]

On 12/6/10 3:54 PM, Drew Adams wrote:
> Some symbols, such as t and nil (and all keywords, such as :foobar) are
> self-evaluating, meaning that they act just like variables whose values are the
> symbols themselves.  You do not need to quote self-evaluating symbols in an
> evaluation context.  Other symbols (e.g. i, foobar) you do need to quote, if you
> want not the value of the symbol (e.g. it might not have a value) but the symbol
> itself.
>
> But all characters are self-evaluating, so ?i evaluates to ?i.

And it might be worth mentioning that "self-evaluating form" is Lisp
terminology for "constant".  Other examples besides characters include:
strings; some symbols such as t, nil, and :keyword; and vectors.

--
Kevin Rodgers
Denver, Colorado, USA