Update README and example regexp.conf for conditional regular expressions.

2 files changed, 12 insertions, 2 deletions

diff --git a/README b/README
index 7bc80da..8d83db8 100644
--- a/README
+++ b/README
@@ -60,9 +60,15 @@ General syntax of configuration files:
   numbers but not both.
 - Channel intervals (e.g. 1-10) can be used for channel numbers.
 
-Syntax of regexp.conf line is "Channel_list:Parsed_epg_field=Regexp" with:
-- Parsed_epg_field is the EPG field for which the regular expression is applied
+Syntax of regexp.conf line is 
+"Channel_list:Parsed_field?Conditional_field~Conditional_Regexp=Regexp" with:
+- Parsed_field is the EPG field for which the regular expression is applied
   with available field names title, shorttext and description.
+- Conditional_field and Conditional_Regexp are optional parameters to control 
+  when Regexp is applied.
+- Conditional_field is identical to Parsed_field.
+- Conditional_Regexp has to be a Perl-style 'm/PATTERN/' as described below
+  except it is only used for matching (i.e. backreferences are ignored).
 - Regular expressions can be used in different ways: Perl-style 
   's/PATTERN/REPLACEMENT/' and 'm/PATTERN/' operators or simply using 'PATTERN'
   of which the latter two use named backreferences.
diff --git a/epgfixer/regexp.conf b/epgfixer/regexp.conf
index a7ef68c..5886428 100644
--- a/epgfixer/regexp.conf
+++ b/epgfixer/regexp.conf
@@ -19,5 +19,9 @@
 # Matches 'foo' case-insensitively
 #description=m/foo/i
 
+# Example of a conditional regexp
+# regexp "s/foo/bar/" is applied to description only if title matches "foo"
+#description?title~m/foo/=s/foo/bar/
+
 # Example of disabled regexp:
 #!title=m/^(?:Movie: |Document: )(?<title>.*)$/