The value of the set special form is undefined, and it is an error to use a set form in a value requiring position. For example,
formula vobeyspaces : |
is conceptually equivalent
formula vobeyspaces : |
where (return) invokes the calling continuation with no arguments. For more information on return see section . In version 3.0 set will continue to return the value being assigned to the location, but an error will be signalled in the future.