Here are some examples of doing certain commonly desired things with
Lisp expressions:
-
Make TAB in C mode just insert a tab if point is in the middle of a
line.
| | (setq c-tab-always-indent nil)
|
Here we have a variable whose value is normally t for `true'
and the alternative is nil for `false'.
-
Make searches case sensitive by default (in all buffers that do not
override this).
| | (setq-default case-fold-search nil)
|
This sets the default value, which is effective in all buffers that do
not have local values for the variable. Setting case-fold-search
with setq affects only the current buffer's local value, which
is not what you probably want to do in an init file.
-
Specify your own email address, if Emacs can't figure it out correctly.
| | (setq user-mail-address "coon@yoyodyne.com")
|
Various Emacs packages that need your own email address use the value of
user-mail-address.
-
Make Text mode the default mode for new buffers.
| | (setq default-major-mode 'text-mode)
|
Note that text-mode is used because it is the command for
entering Text mode. The single-quote before it makes the symbol a
constant; otherwise, text-mode would be treated as a variable
name.
-
Set up defaults for the Latin-1 character set
which supports most of the languages of Western Europe.
| | (set-language-environment "Latin-1")
|
-
Turn on Auto Fill mode automatically in Text mode and related modes.
| | (add-hook 'text-mode-hook
'(lambda () (auto-fill-mode 1)))
|
This shows how to add a hook function to a normal hook variable
(@pxref{Hooks}). The function we supply is a list starting with
lambda, with a single-quote in front of it to make it a list
constant rather than an expression.
It's beyond the scope of this manual to explain Lisp functions, but for
this example it is enough to know that the effect is to execute
(auto-fill-mode 1) when Text mode is entered. You can replace
that with any other expression that you like, or with several
expressions in a row.
Emacs comes with a function named turn-on-auto-fill whose
definition is (lambda () (auto-fill-mode 1)). Thus, a simpler
way to write the above example is as follows:
| | (add-hook 'text-mode-hook 'turn-on-auto-fill)
|
-
Load the installed Lisp library named `foo' (actually a file
`foo.elc' or `foo.el' in a standard Emacs directory).
When the argument to load is a relative file name, not starting
with `/' or `~', load searches the directories in
load-path (@pxref{Lisp Libraries}).
-
Load the compiled Lisp file `foo.elc' from your home directory.
Here an absolute file name is used, so no searching is done.
-
Tell Emacs to find the definition for the function
myfunction
by loading a Lisp library named `mypackage' (i.e. a file
`mypackage.elc' or `mypackage.el'):
| | (autoload 'myfunction "mypackage" "Do what I say." t)
|
Here the string "Do what I say." is the function's
documentation string. You specify it in the autoload
definition so it will be available for help commands even when the
package is not loaded. The last argument, t, indicates that
this function is interactive; that is, it can be invoked interactively
by typing M-x myfunction RET or by binding it to a key.
If the function is not interactive, omit the t or use
nil.
-
Rebind the key C-x l to run the function
make-symbolic-link.
| | (global-set-key "\C-xl" 'make-symbolic-link)
|
or
| | (define-key global-map "\C-xl" 'make-symbolic-link)
|
Note once again the single-quote used to refer to the symbol
make-symbolic-link instead of its value as a variable.
-
Do the same thing for Lisp mode only.
| | (define-key lisp-mode-map "\C-xl" 'make-symbolic-link)
|
-
Redefine all keys which now run
next-line in Fundamental mode
so that they run forward-line instead.
| | (substitute-key-definition 'next-line 'forward-line
global-map)
|
-
Make C-x C-v undefined.
| | (global-unset-key "\C-x\C-v")
|
One reason to undefine a key is so that you can make it a prefix.
Simply defining C-x C-v anything will make C-x C-v a
prefix, but C-x C-v must first be freed of its usual non-prefix
definition.
-
Make `$' have the syntax of punctuation in Text mode.
Note the use of a character constant for `$'.
| | (modify-syntax-entry ?\$ "." text-mode-syntax-table)
|
-
Enable the use of the command
narrow-to-region without confirmation.
| | (put 'narrow-to-region 'disabled nil)
|