Debra Cameron - Learning GNU Emacs, 3rd Edition

Table A-7. Completion ( Chapter 14 Chapter 14. The Help System Emacs has the most comprehensive help facility of any text editor—and one of the best such facilities of any program at all. In fact, the Emacs help facilities probably cut down the time it took for us to write this book by an order of magnitude, and they can help you immeasurably in your ongoing quest to learn more about Emacs. In this chapter, we describe Emacs help in the following areas: • The tutorial. • The help key ( C-h ) and Help menu, which allow you to get help on a wide variety of topics. • The help facilities of complex commands like query-replace and dired . • Navigating Emacs manuals and using the info documentation reader. • Completion , in which Emacs helps you finish typing names of functions, variables, filenames, and more. Completion not only saves you time and helps you complete names of functions you know about but can help you discover new commands and variables. )

Table A-8. Miscellaneous

The tables in this appendix list the most useful Lisp packages that come with Emacs. All Lisp packages are typically located in the directory emacs-source/lisp, where emacs-source is the directory in which you placed the Emacs source distribution. We have omitted all of the packages that provide "basic" Emacs support; likewise, we have omitted many packages whose functionality is obsolete or unspeakably obscure.

While some of these packages are described in some detail in this book, most aren't; you will have to rely on GNU Emacs' help for precise descriptions of what the package does. See Chapter 14 Chapter 14. The Help System Emacs has the most comprehensive help facility of any text editor—and one of the best such facilities of any program at all. In fact, the Emacs help facilities probably cut down the time it took for us to write this book by an order of magnitude, and they can help you immeasurably in your ongoing quest to learn more about Emacs. In this chapter, we describe Emacs help in the following areas: • The tutorial. • The help key ( C-h ) and Help menu, which allow you to get help on a wide variety of topics. • The help facilities of complex commands like query-replace and dired . • Navigating Emacs manuals and using the info documentation reader. • Completion , in which Emacs helps you finish typing names of functions, variables, filenames, and more. Completion not only saves you time and helps you complete names of functions you know about but can help you discover new commands and variables. for details about help; the most important help commands you will need for finding out about the functionality of Lisp packages are C-h p(for finder-by-keyword), C-h f(for describe-function), and C-h m(for describe-mode).

C-h pis especially helpful. It lets you navigate through a hierarchy of information about all packages available on your system, from general areas of functionality, like those in the tables in this appendix, to the C-h minformation about each individual mode. Unfortunately, the detailed information is sometimes incomplete and also lists many packages that could not possibly be interesting to anyone other than hard-core Emacs customizers.

Wherever it is reasonable, the tables in this appendix give commands that "start" the package. This startup information has the following meanings:

• If the package implements a major mode, the startup command is the function that puts Emacs into this major mode.

• If the package implements a major mode that is automatically loaded when you visit a file with a certain suffix, we list "suffix suffixname " in addition to the startup command.

• If the package implements a minor mode, the startup command is the function that puts Emacs into this minor mode.

• If the package implements a set of general-purpose functions, we've tried to pick the most "typical" of these functions. For example, the studlypackage implements three commands. We arbitrarily picked studlify-regionas one way to invoke this package. If there isn't any reasonable choice, we list "many."

Finally, a word on using the packages. Some packages are automatically loaded when Emacs starts; some are loaded when you visit a file with the appropriate suffix (such as many of the modes for programming languages); some are automatically loaded whenever you give the appropriate command (for example, M-x shell Enterloads the package shell.el for shell-mode); and some are never automatically loaded. So how do you know which is which?