Commit 09094f28 authored by Chong Yidong's avatar Chong Yidong
Browse files

* cl.texi (Argument Lists): Clarify explicit keyword arguments.

parent 5c4634c1
2009-10-07 Chong Yidong <cyd@stupidchicken.com>
* cl.texi (Argument Lists): Clarify explicit keyword arguments.
2009-10-07 Juanma Barranquero <lekktu@gmail.com>
* makefile.w32-in (INFO_TARGETS, DVI_TARGETS, clean): Add eieio, ede.
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......@@ -457,15 +457,26 @@ argument @code{b} as well, since @code{(foo 1 :c 2)} would bind
@code{b} to the keyword @code{:c}, then signal an error because
@code{2} is not a valid keyword.
If a @var{keyword} symbol is explicitly specified in the argument
list as shown in the above diagram, then that keyword will be
used instead of just the variable name prefixed with a colon.
You can specify a @var{keyword} symbol which does not begin with
a colon at all, but such symbols will not be self-quoting; you
will have to quote them explicitly with an apostrophe in the
function call.
You can also explicitly specify the keyword argument; it need not be
simply the variable name prefixed with a colon. For example,
@example
(defun* bar (&key (a 1) ((baz b) 4)))
@end example
@noindent
specifies a keyword @code{:a} that sets the variable @code{a} with
default value 1, as well as a keyword @code{baz} that sets the
variable @code{b} with default value 4. In this case, because
@code{baz} is not self-quoting, you must quote it explicitly in the
function call, like this:
@example
(bar :a 10 'baz 42)
@end example
Ordinarily it is an error to pass an unrecognized keyword to
Ordinarily, it is an error to pass an unrecognized keyword to
a function, e.g., @code{(foo 1 2 :c 3 :goober 4)}. You can ask
Lisp to ignore unrecognized keywords, either by adding the
marker @code{&allow-other-keys} after the keyword section
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