lib/html2rss/attribute_post_processors/substring.rb in html2rss-0.7.0 vs lib/html2rss/attribute_post_processors/substring.rb in html2rss-0.8.0

@@ -1,22 +1,28 @@
 module Html2rss
   module AttributePostProcessors
     ## Returns a defined part of a String.
     #
+    # Both parameters must be an Integer and they can be negative.
     # The +end+ parameter can be omitted, in that case it will not cut the
     # String at the end.
     #
+    # A Regexp or a MatchString is not supported.
+    #
+    # See the [`String#[]`](https://ruby-doc.org/core/String.html#method-i-5B-5D)
+    # documentation for more information.
+    #
     # Imagine this HTML:
     #    <h1>Foo bar and baz<h1>
     #
     # YAML usage example:
     #    selectors:
     #      title:
     #        selector: h1
     #        post_process:
-    #         name: substring
-    #         start: 4
-    #         end: 6
+    #          name: substring
+    #          start: 4
+    #          end: 6
     #
     # Would return:
     #    'bar'
     class Substring
       def initialize(value, env)