[elpa] externals/compat 8ea6272 86/99: Add define-error compatibility function

[ELPA Syncer]

branch: externals/compat
commit 8ea6272c3b09be5a3e0f860e7026bfe6c312e5ff
Author: Philip Kaludercic <philipk@posteo.net>
Commit: Philip Kaludercic <philipk@posteo.net>

    Add define-error compatibility function
---
 compat-24.4.el  | 20 ++++++++++++++++++++
 compat-tests.el |  1 +
 2 files changed, 21 insertions(+)

diff --git a/compat-24.4.el b/compat-24.4.el
index dcc61d2..9ee75d8 100644
--- a/compat-24.4.el
+++ b/compat-24.4.el
@@ -149,5 +149,25 @@ non-nil."
         (setcdr last nil)))
   list)
 
+(compat-defun define-error (name message &optional parent)
+  "Define NAME as a new error signal.
+MESSAGE is a string that will be output to the echo area if such an error
+is signaled without being caught by a `condition-case'.
+PARENT is either a signal or a list of signals from which it inherits.
+Defaults to `error'."
+  (unless parent (setq parent 'error))
+  (let ((conditions
+         (if (consp parent)
+             (apply #'append
+                    (mapcar (lambda (parent)
+                              (cons parent
+                                    (or (get parent 'error-conditions)
+                                        (error "Unknown signal `%s'" parent))))
+                            parent))
+           (cons parent (get parent 'error-conditions)))))
+    (put name 'error-conditions
+         (delete-dups (copy-sequence (cons name conditions))))
+    (when message (put name 'error-message message))))
+
 (provide 'compat-24.4)
 ;;; compat-24.4.el ends here
diff --git a/compat-tests.el b/compat-tests.el
index 6adeac6..bfa8005 100644
--- a/compat-tests.el
+++ b/compat-tests.el
@@ -29,6 +29,7 @@
 ;;
 ;; - buffer-local-boundp (`buffer-local-boundp')
 ;; - count-windows (`compat--count-windows')
+;; - define-error (`compat--define-error')
 ;; - directory-empty-p (`compat--directory-empty-p')
 ;; - directory-files (`compat--directory-files')
 ;; - dlet (`compat--dlet')