added alias and implication importer

app/logical/alias_and_implication_importer.rb

@@ -0,0 +1,65 @@
+class AliasAndImplicationImporter
+  attr_accessor :text, :commands, :forum_id
+  
+  def initialize(text, forum_id)
+    @forum_id = forum_id
+    @text = text
+  end
+  
+  def process!
+    tokens = tokenize(text)
+    parse(tokens)
+  end
+  
+private
+  
+  def tokenize(text)
+    text.gsub!(/^\s+/, "")
+    text.gsub!(/\s+$/, "")
+    text.gsub!(/ {2,}/, " ")
+    text.split(/\r\n|\r|\n/).map do |line|
+      if line =~ /create alias (\S+) -> (\S+)/i
+        [:create_alias, $1, $2]
+      elsif line =~ /create implication (\S+) -> (\S+)/i
+        [:create_implication, $1, $2]
+      elsif line =~ /remove alias (\S+) -> (\S+)/i
+        [:remove_alias, $1, $2]
+      elsif line =~ /remove implication (\S+) -> (\S+)/i
+        [:remove_implication, $1, $2]
+      elsif line.empty?
+        # do nothing
+      else
+        raise "Unparseable line: #{line}"
+      end
+    end
+  end
+  
+  def parse(tokens)
+    ActiveRecord::Base.transaction do
+      tokens.map do |token|
+        case token[0]
+        when :create_alias
+          tag_alias = TagAlias.create(:forum_topic_id => forum_id, :status => "pending", :antecedent_name => token[1], :consequent_name => token[2])
+          tag_alias.delay.process!
+      
+        when :create_implication
+          tag_implication = TagImplication.create(:forum_topic_id => forum_id, :status => "pending", :antecedent_name => token[1], :consequent_name => token[2])
+          tag_implication.delay.process!
+      
+        when :remove_alias
+          tag_alias = TagAlias.where("antecedent_name = ?", token[1]).first
+          raise "Alias for #{token[1]} not found" if tag_alias.nil?
+          tag_alias.destroy
+      
+        when :remove_implication
+          tag_implication = TagImplication.where("antecedent_name = ? and consequent_name = ?", token[1], token[2]).first
+          raise "Implication for #{token[1]} not found" if tag_implication.nil?
+          tag_implication.destroy
+      
+        else
+          raise "Unknown token: #{token[0]}"
+        end
+      end
+    end
+  end
+end