RE: [External] : Exiting from mapc

[Drew Adams <drew.adams@oracle.com>]

> > > How can I exit when encountering 'safg or 'nogo
> >
> > As usual, wrap with a `catch', and` throw' to it whenever you like.
> 
> Does the catch statement belong before mapc?

Yes - "wrap".


(defun amazones-falkotr-kntlr (actm-seqr)
  (catch 'RTFM
    (mapc (lambda (...)
            <Do whatever, and `throw' any value,
             from anywhere here, to 'RTFM>)
          actm-seqr))))

1. `C-h f catch'

2. https://www.gnu.org/software/emacs/manual/html_node/elisp/Catch-and-Throw.html

Learning to use `catch' and `throw' with code
such as iteration is basic.  And catch/throw is
a building block for implementing other iteration
etc. constructs.

The Elisp code that Emacs provides so freely to
you is a great place to learn about Elisp.  Grep
for `catch' there...

Here's a simple example:

(defmacro while-no-input (&rest body)
  "..."
  (declare (debug t) (indent 0))
  (let ((catch-sym (make-symbol "input")))
    `(with-local-quit
       (catch ',catch-sym
	 (let ((throw-on-input ',catch-sym))
	   (or (input-pending-p)
	       (progn ,@body)))))))

Here's another:

(defun get-window-with-predicate (predicate &optional minibuf all-frames default)
  "..."
  (catch 'found
    (dolist (window (window-list-1
		     (next-window nil minibuf all-frames)
		     minibuf all-frames))
      (when (funcall predicate window)
	(throw 'found window)))
    default))

The Elisp manual makes great bedtime reading.
Time better spent than asking help-gnu-emacs,
perhaps.