Add new function mailcap-mime-type-to-extension

* lisp/net/mailcap.el (mailcap-mime-type-to-extension): Add a new
helper function to do the reverse of `mailcap-file-name-to-mime-type'.

1 files changed, 8 insertions, 0 deletions

diff --git a/lisp/net/mailcap.el b/lisp/net/mailcap.el
index df6bdd1aba5..0ad1a53e846 100644
--- a/lisp/net/mailcap.el
+++ b/lisp/net/mailcap.el
@@ -1068,6 +1068,14 @@ For instance, \"foo.png\" will result in \"image/png\"."
        (match-string 1 file-name)
      "")))
 
+(defun mailcap-mime-type-to-extension (mime-type)
+  "Return a file name extension based on a mime type.
+For instance, `image/png' will result in `png'."
+  (intern (cadr (split-string (if (symbolp mime-type)
+                                  (symbol-name mime-type)
+                                mime-type)
+                              "/"))))
+
 (defun mailcap-mime-types ()
   "Return a list of MIME media types."
   (mailcap-parse-mimetypes)