conditions.lisp

(in-package #:serapeum)

(defmacro ignoring (type &body body)
  "An improved version of `ignore-errors`.

The behavior is the same: if an error occurs in the body, the form
returns two values, `nil` and the condition itself.

`ignoring` forces you to specify the kind of error you want to ignore:

    (ignoring parse-error
      ...)

I call it an improvement because I think `ignore-errors` is too broad:
by hiding all errors it becomes itself a source of bugs.

Of course you can still ignore all errors, at the cost of one extra
character:

    (ignoring error
      ...)

NB `(ignoring t)` is a bad idea."
  `(handler-case
       (progn ,@body)
     (,type (c)
       (values nil c))))

(defun maybe-invoke-restart (restart &rest values)
  "When RESTART is active, invoke it with VALUES."
  (when (find-restart restart)
    (apply #'invoke-restart restart values)))