Modes are used to tailor the editor to the type of the file being edited in a buffer. They are normally a file of Lisp which installs the buffer-local key bindings and variables which are needed for that type of file.
For example, C-mode is a mode used to edit C source code, its main function is to try to indent each line to its correct position automatically.
The name of the mode active in the current buffer is displayed in the status line, inside the square brackets.
At present there are only a small number of modes available. It is fairly straightforward to write a mode for other classes of file though. See section Writing Modes.
Most of the modes for editing programming languages use the command Meta-; to insert a comment place-holder, the cursor is moved to where you should type the body of the comment.
Go to the first, previous, next, last section, table of contents.