GNU Info

(emacs)Lisp Libraries

---

Next: Lisp Interaction Prev: Executing Lisp Up: Building

---

Enter node , (file) or (file)node

Libraries of Lisp Code for Emacs
================================

   Lisp code for Emacs editing commands is stored in files whose names
conventionally end in `.el'.  This ending tells Emacs to edit them in
Emacs-Lisp mode (Note: Executing Lisp).

   To execute a file of Emacs Lisp code, use `M-x load-file'.  This
command reads a file name using the minibuffer and then executes the
contents of that file as Lisp code.  It is not necessary to visit the
file first; in any case, this command reads the file as found on disk,
not text in an Emacs buffer.

   Once a file of Lisp code is installed in the Emacs Lisp library
directories, users can load it using `M-x load-library'.  Programs can
load it by calling `load-library', or with `load', a more primitive
function that is similar but accepts some additional arguments.

   `M-x load-library' differs from `M-x load-file' in that it searches
a sequence of directories and tries three file names in each directory.
Suppose your argument is LIB; the three names are `LIB.elc', `LIB.el',
and lastly just `LIB'.  If `LIB.elc' exists, it is by convention the
result of compiling `LIB.el'; it is better to load the compiled file,
since it will load and run faster.

   If `load-library' finds that `LIB.el' is newer than `LIB.elc' file,
it issues a warning, because it's likely that somebody made changes to
the `.el' file and forgot to recompile it.

   Because the argument to `load-library' is usually not in itself a
valid file name, file name completion is not available.  Indeed, when
using this command, you usually do not know exactly what file name will
be used.

   The sequence of directories searched by `M-x load-library' is
specified by the variable `load-path', a list of strings that are
directory names.  The default value of the list contains the directory
where the Lisp code for Emacs itself is stored.  If you have libraries
of your own, put them in a single directory and add that directory to
`load-path'.  `nil' in this list stands for the current default
directory, but it is probably not a good idea to put `nil' in the list.
If you find yourself wishing that `nil' were in the list, most likely
what you really want to do is use `M-x load-file' this once.

   Often you do not have to give any command to load a library, because
the commands defined in the library are set up to "autoload" that
library.  Trying to run any of those commands calls `load' to load the
library; this replaces the autoload definitions with the real ones from
the library.

   Emacs Lisp code can be compiled into byte-code which loads faster,
takes up less space when loaded, and executes faster.  Note: Byte
Compilation.  By convention, the compiled code
for a library goes in a separate file whose name consists of the
library source file with `c' appended.  Thus, the compiled code for
`foo.el' goes in `foo.elc'.  That's why `load-library' searches for
`.elc' files first.

   By default, Emacs refuses to load compiled Lisp files which were
compiled with XEmacs, a modified versions of Emacs--they can cause
Emacs to crash.  Set the variable `load-dangerous-libraries' to `t' if
you want to try loading them.


automatically generated by info2www version 1.2.2.9