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+The Porter 2 stemmer
+====================
+This is the Porter 2 stemming algorithm, as described at 
+http://snowball.tartarus.org/algorithms/english/stemmer.html
+The original paper is:
+
+Porter, 1980, "An algorithm for suffix stripping", _Program_, Vol. 14,
+no. 3, pp 130-137
+
+Features of this implementation
+===============================
+This stemmer is written in pure Ruby, making it easy to modify for language variants. 
+For instance, the original Porter stemmer only works for American English and does
+not recognise British English's '-ise' as an alternate spelling of '-ize'. This 
+implementation has been extended to handle correctly British English.
+
+This stemmer also features a comprehensive test set of over 29,000 words, taken from the 
+{Porter 2 stemmer website}[http://snowball.tartarus.org/algorithms/english/stemmer.html].
+
+Files
+=====
+Constants for the stemmer are in the Porter2 module.
+
+Procedures that implement the stemmer are added to the String class.
+
+The stemmer algorithm is implemented in the String#porter2_stem procedure.
+
+Internationalisation
+====================
+There isn't much, as this is a stemmer that only works for English.
+
+The `gb_english` flag to the various procedures allows the stemmer to treat the British 
+English '-ise' the same as the American English '-ize'.
+
+Longest suffixes
+================
+Several places in the algorithm require matching the longest suffix of a word. The 
+regexp engine in Ruby 1.9 seems to handle alterntives in regexps by finding the 
+alternative that matches at the first position in the string. As we're only talking 
+about suffixes, that first match is also the longest suffix. If the regexp engine changes,
+this behaviour may change and break the stemmer.
+
+Usage
+=====
+Call the String#porter2_stem or String#stem methods on a string to return its stem
+    "consistency".stem       # => "consist"
+    "knitting".stem          # => "knit"
+    "articulated".stem       # => "articul"
+    "nationalize".stem       # => "nation"
+    "nationalise".stem       # => "nationalis"
+    "nationalise".stem(true) # => "nation"
+
+Author
+======
+The Porter 2 stemming algorithm was developed by 
+[Martin Porter](http://snowball.tartarus.org/algorithms/english/stemmer.html). 
+This implementation is by [Neil Smith](http://www.njae.me.uk).
+