Variable: mail-citation-prefix-regexp
mail-citation-prefix-regexp is a customizable variable defined in
sendmail.el.gz.
Value
"\\([ ]*\\(\\w\\|[_.]\\)+>+\\|[ ]*[>|]\\)+"
Documentation
Regular expression to match a citation prefix plus whitespace.
It should match whatever sort of citation prefixes you want to handle,
with whitespace before and after; it should also match just whitespace.
The default value matches citations like foo-bar> plus whitespace.
This variable was added, or its default value changed, in Emacs 24.1.
Source Code
;; Defined in /usr/src/emacs/lisp/mail/sendmail.el.gz
;;;###autoload
(defcustom mail-citation-prefix-regexp
(purecopy "\\([ \t]*\\(\\w\\|[_.]\\)+>+\\|[ \t]*[>|]\\)+")
"Regular expression to match a citation prefix plus whitespace.
It should match whatever sort of citation prefixes you want to handle,
with whitespace before and after; it should also match just whitespace.
The default value matches citations like `foo-bar>' plus whitespace."
:type 'regexp
:version "24.1")