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Based on information in the file name or in the file itself, Emacs automatically selects a major mode for the new buffer when a file is visited. It also processes local variables specified in the file text.
Fundamental mode is a major mode that is not specialized for anything in particular. Other major modes are defined in effect by comparison with this one—their definitions say what to change, starting from Fundamental mode. The
fundamental-mode
function does not run any hooks; you're not supposed to customize it. (If you want Emacs to behave differently in Fundamental mode, change the global state of Emacs.)
This function establishes the proper major mode and buffer-local variable bindings for the current buffer. First it calls
set-auto-mode
, then it runshack-local-variables
to parse, and bind or evaluate as appropriate, the file's local variables.If the find-file argument to
normal-mode
is non-nil
,normal-mode
assumes that thefind-file
function is calling it. In this case, it may process a local variables list at the end of the file and in the ‘-*-’ line. The variableenable-local-variables
controls whether to do so. See Local Variables in Files, for the syntax of the local variables section of a file.If you run
normal-mode
interactively, the argument find-file is normallynil
. In this case,normal-mode
unconditionally processes any local variables list.
normal-mode
usescondition-case
around the call to the major mode function, so errors are caught and reported as a ‘File mode specification error’, followed by the original error message.
This function selects the major mode that is appropriate for the current buffer. It may base its decision on the value of the ‘-*-’ line, on the visited file name (using
auto-mode-alist
), on the ‘#!’ line (usinginterpreter-mode-alist
), or on the file's local variables list. However, this function does not look for the ‘mode:’ local variable near the end of a file; thehack-local-variables
function does that. See How Major Modes are Chosen.
This variable holds the default major mode for new buffers. The standard value is
fundamental-mode
.If the value of
default-major-mode
isnil
, Emacs uses the (previously) current buffer's major mode for the major mode of a new buffer. However, if that major mode symbol has amode-class
property with valuespecial
, then it is not used for new buffers; Fundamental mode is used instead. The modes that have this property are those such as Dired and Rmail that are useful only with text that has been specially prepared.
This function sets the major mode of buffer to the value of
default-major-mode
. If that variable isnil
, it uses the current buffer's major mode (if that is suitable).The low-level primitives for creating buffers do not use this function, but medium-level commands such as
switch-to-buffer
andfind-file-noselect
use it whenever they create buffers.
The value of this variable determines the major mode of the initial ‘*scratch*’ buffer. The value should be a symbol that is a major mode command. The default value is
lisp-interaction-mode
.
This variable contains an association list of file name patterns (regular expressions; see Regular Expressions) and corresponding major mode commands. Usually, the file name patterns test for suffixes, such as ‘.el’ and ‘.c’, but this need not be the case. An ordinary element of the alist looks like
(
regexp.
mode-function)
.For example,
(("\\`/tmp/fol/" . text-mode) ("\\.texinfo\\'" . texinfo-mode) ("\\.texi\\'" . texinfo-mode) ("\\.el\\'" . emacs-lisp-mode) ("\\.c\\'" . c-mode) ("\\.h\\'" . c-mode) ...)When you visit a file whose expanded file name (see File Name Expansion) matches a regexp,
set-auto-mode
calls the corresponding mode-function. This feature enables Emacs to select the proper major mode for most files.If an element of
auto-mode-alist
has the form(
regexp functiont)
, then after calling function, Emacs searchesauto-mode-alist
again for a match against the portion of the file name that did not match before. This feature is useful for uncompression packages: an entry of the form("\\.gz\\'"
functiont)
can uncompress the file and then put the uncompressed file in the proper mode according to the name sans ‘.gz’.Here is an example of how to prepend several pattern pairs to
auto-mode-alist
. (You might use this sort of expression in your init file.)(setq auto-mode-alist (append ;; File name (within directory) starts with a dot. '(("/\\.[^/]*\\'" . fundamental-mode) ;; File name has no dot. ("[^\\./]*\\'" . fundamental-mode) ;; File name ends in ‘.C’. ("\\.C\\'" . c++-mode)) auto-mode-alist))
This variable specifies major modes to use for scripts that specify a command interpreter in a ‘#!’ line. Its value is a list of elements of the form
(
interpreter.
mode)
; for example,("perl" . perl-mode)
is one element present by default. The element says to use mode mode if the file specifies an interpreter which matches interpreter. The value of interpreter is actually a regular expression.This variable is applicable only when the
auto-mode-alist
does not indicate which major mode to use.