19.4.1 Simple Types

This section describes all the simple customization types.

sexp

The value may be any Lisp object that can be printed and read back. You can use sexp as a fall-back for any option, if you don’t want to take the time to work out a more specific type to use.

integer

The value must be an integer, and is represented textually in the customization buffer.

number

The value must be a number, and is represented textually in the customization buffer.

string

The value must be a string, and the customization buffer shows just the contents, with no delimiting ‘"’ characters and no quoting with ‘\’.

regexp

Like string except that the string must be a valid regular expression.

character

The value must be a character code. A character code is actually an integer, but this type shows the value by inserting the character in the buffer, rather than by showing the number.

file

The value must be a file name, and you can do completion with M-TAB.

(file :must-match t)

The value must be a file name for an existing file, and you can do completion with M-TAB.

directory

The value must be a directory name, and you can do completion with M-TAB.

symbol

The value must be a symbol. It appears in the customization buffer as the name of the symbol.

function

The value must be either a lambda expression or a function name. When it is a function name, you can do completion with M-TAB.

variable

The value must be a variable name, and you can do completion with M-TAB.

face

The value must be a symbol which is a face name.

boolean

The value is boolean—either nil or t. Note that by using choice and const together (see the next section), you can specify that the value must be nil or t, but also specify the text to describe each value in a way that fits the specific meaning of the alternative.