ToC DocOverview CGDoc RelNotes Index PermutedIndex
Allegro CL
Home Previous Up Next Table of Contents Index
  ANSI Common Lisp   9 Conditions   9.2 Dictionary of Conditions

9.2.43 muffle-warning Restart

Data Arguments Required:
None.

Description:
This restart is established by warn so that handlers of warning conditions have a way to tell warn that a warning has already been dealt with and that no further action is warranted.

Examples:
 (defvar *all-quiet* nil)  *ALL-QUIET*
 (defvar *saved-warnings* '())  *SAVED-WARNINGS*
 (defun quiet-warning-handler (c)
   (when *all-quiet*
     (let ((r (find-restart 'muffle-warning c)))
       (when r 
         (push c *saved-warnings*)
         (invoke-restart r)))))
  CUSTOM-WARNING-HANDLER
 (defmacro with-quiet-warnings (&body forms)
   `(let ((*all-quiet* t)
          (*saved-warnings* '()))
      (handler-bind ((warning #'quiet-warning-handler))
        ,@forms
        *saved-warnings*)))
  WITH-QUIET-WARNINGS
 (setq saved
   (with-quiet-warnings
     (warn "Situation #1.")
     (let ((*all-quiet* nil))
       (warn "Situation #2."))
     (warn "Situation #3.")))
 Warning: Situation #2.
 (#<SIMPLE-WARNING 42744421> #<SIMPLE-WARNING 42744365>)
 (dolist (s saved) (format t "~&~A~%" s))
 Situation #3.
 Situation #1.
  NIL

See Also:
Section 9.1.4.2 Restarts, Section 9.1.4.2.2 Interfaces to Restarts, invoke-restart, muffle-warning (function), warn

Allegro CL Implementation Details:
None.

Home Previous Up Next Table of Contents Index
© Franz Inc. 1998-2017 - File last updated 01-11-2017