Re: About `defun' in elisp manual

[Pascal J. Bourguignon]

Xue Fuqiao <xfq.free@gmail.com> writes:

> The GNU Emacs Lisp Reference 
> Manual(http://www.gnu.org/software/emacs/manual/html_node/elisp/Defining-Functions.html#Defining-Functions)
>  says:
>      `defun' is the usual way to define new Lisp functions.  It defines the 
> symbol NAME as a function that looks like this:
>           (lambda ARGUMENT-LIST . BODY-FORMS)
>
> Why is the lambda expression a dotted list?  As far as I'm concerned, a 
> normal list is enough.

It is not.


All lists are made of conses, and conses are written (a . d)

A proper list is nil or a cons cell where d is a proper list.

A dotted list is a non-nil atom or a cons cell where d is a dotted list.

A circular list is a circular list or a cons cell where d is a circular
list.   Oops, that definition is circular.  A circular list is a list
where one of the cdr of the cons cells is one of the previous cons
cells.  (But not necessarily the first).



Above, BODY-FORM must be a proper list therefore the lambda expression
is a proper list.



-- 
__Pascal Bourguignon__                     http://www.informatimago.com/
A bad day in () is better than a good day in {}.