From e1e8d2e229f48b3cee765f7cf27ae04ee4401d85 Mon Sep 17 00:00:00 2001 From: Glenn Morris Date: Wed, 26 Jul 2017 12:40:13 -0400 Subject: [PATCH] * doc/lispref/loading.texi (When to Autoload): New section. --- doc/lispref/loading.texi | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) diff --git a/doc/lispref/loading.texi b/doc/lispref/loading.texi index d925c8c8f65..80dcb488983 100644 --- a/doc/lispref/loading.texi +++ b/doc/lispref/loading.texi @@ -468,6 +468,10 @@ runs the real definition as if it had been loaded all along. Autoloading can also be triggered by looking up the documentation of the function or macro (@pxref{Documentation Basics}). +@menu +* When to Autoload:: When to Use Autoload. +@end menu + There are two ways to set up an autoloaded function: by calling @code{autoload}, and by writing a ``magic'' comment in the source before the real definition. @code{autoload} is the low-level @@ -699,6 +703,42 @@ symbol's new function value. If the value of the optional argument function, only a macro. @end defun +@node When to Autoload +@subsection When to Use Autoload +@cindex autoload, when to use + +Do not add an autoload comment unless it is really necessary. +Autoloading code means it is always globally visible. Once an item is +autoloaded, there is no compatible way to transition back to it not +being autoloaded (after people become accustomed to being able to use it +without an explicit load). + +@itemize +@item +The most common items to autoload are the interactive entry points to a +library. For example, if @file{python.el} is a library defining a +major-mode for editing Python code, autoload the definition of the +@code{python-mode} function, so that people can simply use @kbd{M-x +python-mode} to load the library. + +@item +Variables usually don't need to be autoloaded. An exception is if the +variable on its own is generally useful without the whole defining +library being loaded. (An example of this might be something like +@code{find-exec-terminator}.) + +@item +Don't autoload a user option just so that a user can set it. + +@item +Never add an autoload @emph{comment} to silence a compiler warning in +another file. In the file that produces the warning, use +@code{(defvar foo)} to silence an undefined variable warning, and +@code{declare-function} (@pxref{Declaring Functions}) to silence an +undefined function warning; or require the relevant library; or use an +explicit autoload @emph{statement}. +@end itemize + @node Repeated Loading @section Repeated Loading @cindex repeated loading -- 2.39.5