Support for generating "else" statements

lib/oga/ruby/generator.rb

@@ -93,17 +93,29 @@ module Oga
       # @return [String]
       #
       def on_if(ast)
-        cond, body = *ast
+        cond, body, else_body = *ast
 
         cond_str = process(cond)
         body_str = process(body)
 
+        if else_body
+          else_str = process(else_body)
+
+          <<-EOF
+if #{cond_str}
+  #{body_str}
+else
+  #{else_str}
+end
+          EOF
+        else
           <<-EOF
 if #{cond_str}
   #{body_str}
 end
           EOF
         end
+      end
 
       ##
       # Processes a method call node.

lib/oga/ruby/node.rb

@@ -114,6 +114,17 @@ module Oga
         Node.new(:if, [self, yield])
       end
 
+      ##
+      # Adds an "else" statement to the current node.
+      #
+      # This method assumes it's being called only on "if" nodes.
+      #
+      # @return [Oga::Ruby::Node]
+      #
+      def else
+        Node.new(:if, @children + [yield])
+      end
+
       ##
       # Chains two nodes together.
       #

spec/oga/ruby/generator_spec.rb

@@ -67,6 +67,24 @@ if foo
 end
       EOF
     end
+
+    describe 'when using an else clause' do
+      it 'returns a String' do
+        foo = Oga::Ruby::Node.new(:lit, %w{foo})
+        bar = Oga::Ruby::Node.new(:lit, %w{bar})
+        baz = Oga::Ruby::Node.new(:lit, %w{baz})
+
+        statement = foo.if_true { bar }.else { baz }
+
+        @generator.on_if(statement).should == <<-EOF
+if foo
+  bar
+else
+  baz
+end
+        EOF
+      end
+    end
   end
 
   describe '#on_send' do

spec/oga/ruby/node_spec.rb

@@ -99,6 +99,18 @@ describe Oga::Ruby::Node do
     end
   end
 
+  describe '#else' do
+    it 'returns an if-statement with an else clause' do
+      condition = described_class.new(:lit, %w{number})
+      body      = described_class.new(:lit, %w{10})
+      or_else   = described_class.new(:lit, %w{20})
+      statement = condition.if_true { body }.else { or_else }
+
+      statement.type.should == :if
+      statement.to_a.should == [condition, body, or_else]
+    end
+  end
+
   describe '#followed_by' do
     it 'returns a Node chaining two nodes together' do
       node1  = described_class.new(:lit, %w{A})