lib/spandx/content.rb in spandx-0.1.7 vs lib/spandx/content.rb in spandx-0.2.0

@@ -1,27 +1,38 @@
 # frozen_string_literal: true
 
 module Spandx
   class Content
-    attr_reader :tokens, :threshold
+    attr_reader :raw, :threshold
 
-    def initialize(content, threshold: 89.0)
+    def initialize(raw, threshold: 89.0)
       @threshold = threshold
-      @tokens = tokenize(canonicalize(content)).to_set
+      @raw = raw
     end
 
-    def similar?(other)
-      similarity_score(other) > threshold
+    def tokens
+      @tokens ||= tokenize(canonicalize(raw)).to_set
     end
 
-    # https://en.wikibooks.org/wiki/Algorithm_Implementation/Strings/Dice%27s_coefficient#Ruby
-    def similarity_score(other)
-      overlap = (tokens & other.tokens).size
-      total = tokens.size + other.tokens.size
-      100.0 * (overlap * 2.0 / total)
+    def similar?(other, algorithm: :dice_coefficient)
+      case algorithm
+      when :dice_coefficient
+        similarity_score(other) > threshold
+      when :levenshtein
+        similarity_score(other) < threshold
+      end
     end
 
+    def similarity_score(other, algorithm: :dice_coefficient)
+      case algorithm
+      when :dice_coefficient
+        dice_coefficient(other)
+      when :levenshtein
+        Text::Levenshtein.distance(raw, other.raw, 100)
+      end
+    end
+
     private
 
     def canonicalize(content)
       content&.downcase
     end
@@ -30,8 +41,15 @@
       content.to_s.scan(/[a-zA-Z]+/)
     end
 
     def blank?(content)
       content.nil? || content.chomp.strip.empty?
+    end
+
+    # https://en.wikibooks.org/wiki/Algorithm_Implementation/Strings/Dice%27s_coefficient#Ruby
+    def dice_coefficient(other)
+      overlap = (tokens & other.tokens).size
+      total = tokens.size + other.tokens.size
+      100.0 * (overlap * 2.0 / total)
     end
   end
 end