Allow various Gnus and Message address variables to be functions

* doc/misc/gnus.texi (To From Newsgroups):
gnus-ignored-from-addresses can be a function.

* doc/misc/message.texi (Wide Reply):
message-dont-reply-to-names can be a function.

* lisp/gnus/gnus-icalendar.el (gnus-icalendar-identities):
message-alternative-emails can be a function.

* lisp/gnus/gnus-notifications.el (gnus-notifications):
message-alternative-emails can be a function (bug#22315).

* lisp/gnus/gnus-sum.el
(gnus-summary-from-or-to-or-newsgroups):
gnus-ignored-from-addresses can be a function (bug#22315).

2 files changed, 13 insertions, 11 deletions

diff --git a/doc/misc/gnus.texi b/doc/misc/gnus.texi
index 8dd0c1ba9d5..e6e3e7617ee 100644
--- a/doc/misc/gnus.texi
+++ b/doc/misc/gnus.texi
@@ -5042,11 +5042,12 @@ access the @code{X-Newsreader} header:
 
 @item
 @vindex gnus-ignored-from-addresses
-The @code{gnus-ignored-from-addresses} variable says when the @samp{%f}
-summary line spec returns the @code{To}, @code{Newsreader} or
-@code{From} header.  If this regexp matches the contents of the
-@code{From} header, the value of the @code{To} or @code{Newsreader}
-headers are used instead.
+The @code{gnus-ignored-from-addresses} variable says when the
+@samp{%f} summary line spec returns the @code{To}, @code{Newsreader}
+or @code{From} header.  The variable may be a regexp or a predicate
+function.  If this matches the contents of the @code{From}
+header, the value of the @code{To} or @code{Newsreader} headers are
+used instead.
 
 To distinguish regular articles from those where the @code{From} field
 has been swapped, a string is prefixed to the @code{To} or
diff --git a/doc/misc/message.texi b/doc/misc/message.texi
index 761fb772f46..fa4fa4398b4 100644
--- a/doc/misc/message.texi
+++ b/doc/misc/message.texi
@@ -185,8 +185,9 @@ but you can change the behavior to suit your needs by fiddling with the
 
 @vindex message-dont-reply-to-names
 Addresses that match the @code{message-dont-reply-to-names} regular
-expression (or list of regular expressions) will be removed from the
-@code{Cc} header. A value of @code{nil} means exclude your name only.
+expression (or list of regular expressions or a predicate function)
+will be removed from the @code{Cc} header. A value of @code{nil} means
+exclude your name only.
 
 @vindex message-prune-recipient-rules
 @code{message-prune-recipient-rules} is used to prune the addresses
@@ -1672,10 +1673,10 @@ trailing old subject.  In this case,
 
 @item message-alternative-emails
 @vindex message-alternative-emails
-Regexp matching alternative email addresses.  The first address in the
-To, Cc or From headers of the original article matching this variable is
-used as the From field of outgoing messages, replacing the default From
-value.
+Regexp or predicate function matching alternative email addresses.
+The first address in the To, Cc or From headers of the original
+article matching this variable is used as the From field of outgoing
+messages, replacing the default From value.
 
 For example, if you have two secondary email addresses john@@home.net
 and john.doe@@work.com and want to use them in the From field when