@c -*-texinfo-*-
@c This is part of the GNU Emacs Lisp Reference Manual.
-@c Copyright (C) 1990-1995, 1998-1999, 2001-2013 Free Software
+@c Copyright (C) 1990-1995, 1998-1999, 2001-2014 Free Software
@c Foundation, Inc.
@c See the file elisp.texi for copying conditions.
@node Control Structures
was returned by @code{(get-return-code x)}.
To give a more complex example, a simple interpreter for a little
-expression language could look like:
+expression language could look like (note that this example requires
+lexical binding):
@example
(defun evaluate (exp env)
@code{(pred numberp)} is a pattern that simply checks that @code{exp}
is a number, and @code{_} is the catch-all pattern that matches anything.
-Note that the the lambda being the result of the @code{fn} clause is a
-closure (@pxref{Closures}), so the file defining @code{evaluate} must
-have lexical binding enabled (@pxref{Using Lexical Binding}, for how
-to enable it).
-
Here are some sample programs including their evaluation results:
@example
@end example
@end defmac
-@defmac with-demoted-errors body@dots{}
+@defmac with-demoted-errors format body@dots{}
This macro is like a milder version of @code{ignore-errors}. Rather
than suppressing errors altogether, it converts them into messages.
-Use this form around code that is not expected to signal errors, but
+It uses the string @var{format} to format the message.
+@var{format} should contain a single @samp{%}-sequence; e.g.,
+@code{"Error: %S"}. Use @code{with-demoted-errors} around code
+that is not expected to signal errors, but
should be robust if one does occur. Note that this macro uses
@code{condition-case-unless-debug} rather than @code{condition-case}.
@end defmac