Add example on how to add a feed-based filter

README.org

@@ -86,6 +86,8 @@ Likewise, if you use [[https://github.com/rnadler/elfeed-curate][elfeed-curate]]
 
 The variable ~elfeed-export-predicates~ is a list of predicates applied to each entry. An entry that matches all predicates makes it into the export. Each predicate takes one argument: the entry object.
 
+*** By tag
+
 By default, there is a tag-based predicate, which is configured by the variables ~elfeed-export-include-tags~ and ~elfeed-export-exclude-tags~. They're a list of symbols that represent a tag. E.g., to export unread items only, use:
 
 #+begin_src elisp
@@ -94,6 +96,19 @@ By default, there is a tag-based predicate, which is configured by the variables
 
 By default, items tagged as =noexport= are omitted.
 
+*** By feed
+
+To export entries for a certain RSS feed only, use the following configuration snippet:
+
+#+begin_src elisp
+  (add-to-list 'elfeed-export-predicates
+               (lambda (entry)
+                 (let* ((feed (elfeed-entry-feed entry))
+                        (title (elfeed-feed-title feed))
+                        (_url (elfeed-feed-url feed)))
+                   (string-match-p (rx "LWN.net") title))))
+#+end_src
+
 ** COMMENT Attribution :noexport:
 
 The code to generate the table of configuration items was inspired by an idea of [[https://xenodium.com/generating-elisp-org-docs/][Álvaro Ramírez]] (a.k.a. xenodium).

elfeed-export.info

@@ -20,6 +20,11 @@ Configuration
 * Customize export fields::
 * Customize entry filters::
 
+Customize entry filters
+
+* By tag::
+* By feed::
+
 
 
 File: elfeed-export.info,  Node: Introduction,  Next: Installation,  Prev: Top,  Up: Top
@@ -116,24 +121,53 @@ The variable ‘elfeed-export-predicates’ is a list of predicates applied
 to each entry.  An entry that matches all predicates makes it into the
 export.  Each predicate takes one argument: the entry object.
 
-   By default, there is a tag-based predicate, which is configured by
+* Menu:
-the variables ‘elfeed-export-include-tags’ and
+
-‘elfeed-export-exclude-tags’.  They're a list of symbols that represent
+* By tag::
-a tag.  E.g., to export unread items only, use:
+* By feed::
+
+
+File: elfeed-export.info,  Node: By tag,  Next: By feed,  Up: Customize entry filters
+
+3.2.1 By tag
+------------
+
+By default, there is a tag-based predicate, which is configured by the
+variables ‘elfeed-export-include-tags’ and ‘elfeed-export-exclude-tags’.
+They're a list of symbols that represent a tag.  E.g., to export unread
+items only, use:
 
      (add-to-list 'elfeed-export-include-tags 'unread)
 
    By default, items tagged as ‘noexport’ are omitted.
 
+
+File: elfeed-export.info,  Node: By feed,  Prev: By tag,  Up: Customize entry filters
+
+3.2.2 By feed
+-------------
+
+To export entries for a certain RSS feed only, use the following
+configuration snippet:
+
+     (add-to-list 'elfeed-export-predicates
+                  (lambda (entry)
+                    (let* ((feed (elfeed-entry-feed entry))
+                           (title (elfeed-feed-title feed))
+                           (_url (elfeed-feed-url feed)))
+                      (string-match-p (rx "LWN.net") title))))
+
 
 
 Tag Table:
 Node: Top87
-Node: Introduction357
+Node: Introduction406
-Node: Installation1043
+Node: Installation1092
-Node: Configuration1448
+Node: Configuration1497
-Node: Customize export fields2182
+Node: Customize export fields2231
-Node: Customize entry filters3279
+Node: Customize entry filters3328
+Node: By tag3740
+Node: By feed4214
 
 End Tag Table