Extend the comment

diff --git a/parser/grammar b/parser/grammar
index 0017a96479b35acc8e1b1962e63f8844850668a2..5a0c3d53a1a9c8d5f5d270804ed7f3150e0637bc 100644 (file)
--- a/parser/grammar
+++ b/parser/grammar
@@ -3,12 +3,15 @@
 # The grammar defines expressions in the following forms:
 #  TAG - search blog posts that contain the tag;
 #  !TAG - search blog posts that don't contain the tag;
-#  TAG && TAG, TAG & TAG - search blog posts that contain both tags;
-#  TAG || TAG, TAG | TAG - search blog posts that contain any of the tags;
-# Parentheses are allowed to group expressions:
+#  TAG & TAG - search blog posts that contain both tags;
+#  TAG | TAG - search blog posts that contain any of the tags;
+# Parentheses are allowed to group expressions; for example:
 #  TAG & (TAG | TAG)
 #  !(TAG | TAG)
-# and so on. This  is a simple version of the grammar and it allows
+# Allowed operators: conjunction - & &&
+#                    disjunction - | ||
+#                    negation    - !
+# This  is a simple version of the grammar and it allows
 # rather stupid expressions, like !!TAG or ((TAG)); in the future
 # it will be fixed by making the grammar more complex and stricter.