@c -*-texinfo-*-
@c This is part of the GNU Emacs Lisp Reference Manual.
-@c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1998 Free Software Foundation, Inc.
+@c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1998, 2003, 2004 Free Software Foundation, Inc.
@c See the file elisp.texi for copying conditions.
@setfilename ../info/eval
@node Evaluation, Control Structures, Symbols, Top
@c Emacs 19 feature
@defun indirect-function function
+@anchor{Definition of indirect-function}
This function returns the meaning of @var{function} as a function. If
@var{function} is a symbol, then it finds @var{function}'s function
definition and starts over with that value. If @var{function} is not a
symbol, then it returns @var{function} itself.
+This function signals a @code{void-function} error if the final
+symbol is unbound and a @code{cyclic-function-indirection} error if
+there is a loop in the chain of symbols.
+
Here is how you could define @code{indirect-function} in Lisp:
@smallexample
specify limits to the evaluation process, or record recently returned
values. Loading a file also does evaluation (@pxref{Loading}).
- @strong{Note:} it is generally cleaner and more flexible to store a
-function in a data structure, and call it with @code{funcall} or
-@code{apply}, than to store an expression in the data structure and
-evaluate it. Using functions provides the ability to pass information
-to them as arguments.
+ It is generally cleaner and more flexible to store a function in a
+data structure, and call it with @code{funcall} or @code{apply}, than
+to store an expression in the data structure and evaluate it. Using
+functions provides the ability to pass information to them as
+arguments.
@defun eval form
This is the basic function evaluating an expression. It evaluates
@end defun
@deffn Command eval-region start end &optional stream read-function
+@anchor{Definition of eval-region}
This function evaluates the forms in the current buffer in the region
defined by the positions @var{start} and @var{end}. It reads forms from
the region and calls @code{eval} on them until the end of the region is
reached, or until an error is signaled and not handled.
-If @var{stream} is non-@code{nil}, the values that result from
-evaluating the expressions in the region are printed using @var{stream}.
-@xref{Output Streams}.
-
-If @var{read-function} is non-@code{nil}, it should be a function, which
-is used instead of @code{read} to read expressions one by one. This
-function is called with one argument, the stream for reading input. You
-can also use the variable @code{load-read-function} (@pxref{How Programs
-Do Loading}) to specify this function, but it is more robust to use the
+By default, @code{eval-region} does not produce any output. However,
+if @var{stream} is non-@code{nil}, any output produced by output
+functions (@pxref{Output Functions}), as well as the values that
+result from evaluating the expressions in the region are printed using
+@var{stream}. @xref{Output Streams}.
+
+If @var{read-function} is non-@code{nil}, it should be a function,
+which is used instead of @code{read} to read expressions one by one.
+This function is called with one argument, the stream for reading
+input. You can also use the variable @code{load-read-function}
+(@pxref{Definition of load-read-function,, How Programs Do Loading})
+to specify this function, but it is more robust to use the
@var{read-function} argument.
-@code{eval-region} always returns @code{nil}.
+@code{eval-region} does not move point. It always returns @code{nil}.
@end deffn
@cindex evaluation of buffer contents
-@deffn Command eval-current-buffer &optional stream
-This is like @code{eval-region} except that it operates on the whole
-buffer.
+@deffn Command eval-buffer &optional buffer-or-name stream filename unibyte print
+This is similar to @code{eval-region}, but the arguments provide
+different optional features. @code{eval-buffer} operates on the
+entire accessible portion of buffer @var{buffer-or-name}.
+@var{buffer-or-name} can be a buffer, a buffer name (a string), or
+@code{nil} (or omitted), which means to use the current buffer.
+@var{stream} is used as in @code{eval-region}, unless @var{stream} is
+@code{nil} and @var{print} non-@code{nil}. In that case, values that
+result from evaluating the expressions are still discarded, but the
+output of the output functions is printed in the echo area.
+@var{filename} is the file name to use for @code{load-history}
+(@pxref{Unloading}), and defaults to @code{buffer-file-name}
+(@pxref{Buffer File Name}). If @var{unibyte} is non-@code{nil},
+@code{read} converts strings to unibyte whenever possible.
+
+@findex eval-current-buffer
+@code{eval-current-buffer} is an alias for this command.
@end deffn
@defvar max-lisp-eval-depth
+@anchor{Definition of max-lisp-eval-depth}
This variable defines the maximum depth allowed in calls to @code{eval},
@code{apply}, and @code{funcall} before an error is signaled (with error
-message @code{"Lisp nesting exceeds max-lisp-eval-depth"}). This limit,
-with the associated error when it is exceeded, is one way that Lisp
-avoids infinite recursion on an ill-defined function.
+message @code{"Lisp nesting exceeds max-lisp-eval-depth"}).
+
+This limit, with the associated error when it is exceeded, is one way
+Emacs Lisp avoids infinite recursion on an ill-defined function. If
+you increase the value of @code{max-lisp-eval-depth} too much, such
+code can cause stack overflow instead.
@cindex Lisp nesting error
The depth limit counts internal uses of @code{eval}, @code{apply}, and
left, to make sure the debugger itself has room to execute.
@code{max-specpdl-size} provides another limit on nesting.
-@xref{Local Variables}.
+@xref{Definition of max-specpdl-size,, Local Variables}.
@end defvar
@defvar values
The value of this variable is a list of the values returned by all the
expressions that were read, evaluated, and printed from buffers
-(including the minibuffer) by the standard Emacs commands which do this.
-The elements are ordered most recent first.
+(including the minibuffer) by the standard Emacs commands which do
+this. (Note that this does @emph{not} include evaluation in
+@samp{*ielm*} buffers, nor evaluation using @kbd{C-j} in
+@code{lisp-interaction-mode}.) The elements are ordered most recent
+first.
@example
@group
@end group
@end example
@end defvar
+
+@ignore
+ arch-tag: f723a4e0-31b3-453f-8afc-0bf8fd276d57
+@end ignore
HCoop / bpt / emacs.git / blobdiff