find-restart (original) (raw)

ANSI Common Lisp 9 Conditions 9.2 Dictionary of Conditions

Syntax:

find-restart identifier &optional condition

restart

Arguments and Values:

identifier - a non-nil symbol, or a restart.

condition - a condition object, or nil.

restart - a restart or nil.

Description:

find-restart searches for a particular restart in the current dynamic environment.

When condition is non-nil, only those _restarts_are considered that are either explicitly associated with that condition, or not associated with any condition; that is, the excluded _restarts_are those that are associated with a non-empty set of conditions of which the given condition is not an element. If condition is nil, all restarts are considered.

If identifier is a symbol, then the innermost (most recently established) applicable restart with that name is returned.nil is returned if no such restart is found.

If identifier is a currently active restart, then it is returned. Otherwise, nil is returned.

Examples:

(restart-case (let ((r (find-restart 'my-restart))) (format t "~S is named ~S" r (restart-name r))) (my-restart () nil)) #<RESTART 32307325> is named MY-RESTART NIL (find-restart 'my-restart) NIL

Affected By:

Existing restarts.

restart-case, restart-bind, with-condition-restarts.

See Also:

compute-restarts

Notes:

(find-restart identifier) ==(find identifier (compute-restarts) :key :restart-name)

Although anonymous restarts have a name of nil, the consequences are unspecified if nil is given as an identifier. Occasionally, programmers lament that nil is not permissible as an_identifier_ argument. In most such cases, compute-restartscan probably be used to simulate the desired effect.

Allegro CL Implementation Details:

None.