CLtL error re function special form

[Guy Steele <gls@THINK-AQUINAS.ARPA>]

    Date: Thu, 26 Sep 85 08:01:25 edt
    From: Steven Haflich <smh@mit-ems.ARPA>

    Surely this must have been noticed before, but on page 87:

	    function fn				[Special Form]

	    The value of function is always the functional interpretation
	    of fn;  fn is interpreted as if it had appeared in the
	    functional-position of a function invocation.  In particular,
	    if fn is a symbol, the functional definition associated with
	    that symbol is returned;  see symbol-function.  If fn is a
	    lambda-expression ...

    Unlike the function special form, symbol-function does not see lexical
    function bindings.  The reference to symbol-function here was probably
    intended just to convey the distinction between a symbol's `functional'
    interpretation and it's `regular' i.e. symbol-value interpretation.
    But it's wrong, and potentially misleading.

    Fixing the text is awkward because lexical function binding special
    forms are not presented until p.113.  But CLtL is more of a reference
    than a teaching manual.  Perhaps the reference to symbol function
    should just be deleted.

You're right.  The text as it stands is misleading.  Thanks for catching it.

    A similar but less bothersome slip occurs on p.32 about functional data
    types:

	       A symbol may serve as a function;  an attempt to invoke a
	    symbol as a function causes the contents of the symbol's
	    function cell to be used.  See symbol-function and defun.

I don't regard this one as a slip.  In a case such as

	(cons a b)

the symbol CONS is not being invoked as a function; rather, it is evaluated
in a functional context to yield a function object, and it is that object
that is invoked.  In a situation such as

	(apply 'cons args)

then the symbol CONS is invoked as a function (APPLY actually sees the
symbol and must dereference it by fetching the function cell);  in the context

	(apply #'cons args)

it is not (APPLY never sees the symbol, only the function object).
Some examples of this may be needed.

--Guy