6.3 Atomic Sexp Widgets.

The atoms are s-expressions that does not consist of other s-expressions. A string is an atom, while a list is a composite type. You can edit the value of an atom with the following widgets.

The syntax for all the atoms are

TYPE ::= (NAME [KEYWORD ARGUMENT]...  [ VALUE ])

The value, if present, is used to initialize the :value property and must be an expression of the same type as the widget. I.e. the string widget can only be initialized with a string.

All the atom widgets take the same keyword arguments as the editable-field widget.

Widget: string

Allows you to edit a string in an editable field.

Widget: regexp

Allows you to edit a regular expression in an editable field.

Widget: character

Allows you to enter a character in an editable field.

Widget: file

Allows you to edit a file name in an editable field. If you invoke the tag button, you can edit the file name in the mini-buffer with completion.

Keywords:

:must-match

If this is set to non-nil, only existing file names will be allowed in the minibuffer.

Widget: directory

Allows you to edit a directory name in an editable field. Similar to the file widget.

Widget: symbol

Allows you to edit a lisp symbol in an editable field.

Widget: function

Allows you to edit a lambda expression, or a function name with completion.

Widget: variable

Allows you to edit a variable name, with completion.

Widget: integer

Allows you to edit an integer in an editable field.

Widget: number

Allows you to edit a number in an editable field.

Widget: boolean

Allows you to edit a boolean. In lisp this means a variable which is either nil meaning false, or non-nil meaning true.