3.24.4 Defining modes

New modes can be defined using the defmode function.

editor:defmode

Function

Defines a new editor mode called name .

name is a string containing the name of the mode being defined. setup-function is a function which sets up a buffer in this mode. key-bindings is a quoted list of key-binding directions. no-redefine is a boolean: if true, the mode cannot be re-defined. The default value of no-redefine is nil . vars is a quoted list of editor variables and values. aliases is a quoted list of synonyms for name. cleanup-function is a function which is called upon exit from a buffer in this mode. major-p is a boolean: if true, the mode is defined as major, otherwise minor. The default value of major-p is nil .

By default, any mode defined is a minor one--specification of major-mode status is made by supplying a true value for major-p .

defmode is essentially for the purposes of mode specification--not all of the essential definitions required to establish a new Editor mode are made in a defmode call. In the example, below, other required calls are shown.

key-bindings can be defined by supplying a quoted list of bindings, where a binding is a list containing as a first element the (string) name of the Editor command being bound, and as the second, the key binding description (see Advanced Features, for example key-bindings).

The state of Editor variables can be changed in the definition of a mode. These are supplied as a quoted list vars of dotted pairs, where the first element of the pair is the (symbol) name of the editor variable to be changed, and the second is the new value.

Both setup-function and cleanup-function are called with the mode and the buffer locked. They can modify the buffer itself, but they must not wait for anything that happens on another process, and they must not modify the mode (for example by setting a variable in the mode), and must not try to update the display.

As an example tet us define a minor mode, Foo . Foo has a set-up function, called setup-foo-mode . All files with suffix .foo invoke Foo -mode.

Here is the defmode form:

The next piece of code makes .foo files invoke Foo -mode:

(editor:define-file-type-hook ("foo") (buffer type)

   (declare (ignore type))

   (setf (editor:buffer-minor-mode buffer "Foo") t))

The next form defines the set-up function:

(defun setup-foo-mode (buffer)

  (setf (editor:buffer-major-mode buffer) "Lisp")

  (let ((pathname (editor:buffer-pathname buffer)))

    (unless (and pathname

                 (probe-file pathname))

      (editor:insert-string

       (editor:buffer-point buffer)

       #.(format nil ";;; -*- mode :foo -*-~2%(in-package \"CL-USER\")~2%")))))

Now, any files with the suffix .foo invoke the Foo minor mode when loaded into the Editor.