const widget can contain any Lisp expression, but the user is
prohibited from editing it, which is mainly useful as a component of one
of the composite widgets.
The syntax for the
const widget is:
type ::= (const [keyword argument]... [ value ])
The value, if present, is used to initialize the
property and can be any s-expression.
This will display any valid s-expression in an immutable part of the buffer.
There are two variations of the
const widget, namely
function-item. These should contain a
symbol with a variable or function binding. The major difference from
const widget is that they will allow the user to see the
variable or function documentation for the symbol.
An immutable symbol that is bound as a variable.
An immutable symbol that is bound as a function.