Merge branch 'fix_issue_33' of https://github.com/hderms/builder into…

… nil

* 'fix_issue_33' of https://github.com/hderms/builder:
  Update lib/builder/xmlbase.rb
  Squashed commit of the following:

lib/builder/xmlbase.rb

@@ -30,6 +30,13 @@ def initialize(indent=0, initial=0, encoding='utf-8')
       @level  = initial
       @encoding = encoding.downcase
     end
+    def explicit_nil_handling?
+       if  @explicit_nil_handling == true
+         true
+       else
+         false
+       end
+    end
 
     # Create a tag named +sym+.  Other than the first argument which
     # is the tag name, the arguments are the same as the tags
@@ -45,7 +52,8 @@ def tag!(sym, *args, &block)
           attrs ||= {}
           attrs.merge!(arg)
         when nil
-          # do nothing
+          attrs ||= {}
+          attrs.merge!({nil: true}) if explicit_nil_handling?
         else
           text ||= ''
           text << arg.to_s

lib/builder/xmlmarkup.rb

@@ -186,6 +186,7 @@ class XmlMarkup < XmlBase
     def initialize(options={})
       indent = options[:indent] || 0
       margin = options[:margin] || 0
+      @explicit_nil_handling = options[:explicit_nil_handling] || false
       super(indent, margin)
       @target = options[:target] || ""
     end

test/test_markupbuilder.rb

@@ -155,6 +155,22 @@ def test_escaping
     @xml.div { |x| x.text! "<hi>"; x.em("H&R Block") }
     assert_equal %{<div>&lt;hi&gt;<em>H&amp;R Block</em></div>}, @xml.target!
   end
+  def test_explicit_nil_handling
+    b = Builder::XmlMarkup.new explicit_nil_handling: true
+    b.tag! "foo", nil
+    assert_equal %{<foo nil="true"/>}, b.target!
+
+    b = Builder::XmlMarkup.new explicit_nil_handling: true
+    b.div("ns:xml"=>:"&xml;") { |x| x << "<h&i>"; x.em("H&R Block") }
+    assert_equal %{<div ns:xml="&xml;"><h&i><em>H&amp;R Block</em></div>}, b.target!
+
+    b = Builder::XmlMarkup.new explicit_nil_handling: true
+    n = 3
+    b.ol { |x| n.times { x.li(n) } }
+    assert_equal "<ol><li>3</li><li>3</li><li>3</li></ol>", b.target!
+
+
+  end
 
   def test_non_escaping
     @xml.div("ns:xml"=>:"&xml;") { |x| x << "<h&i>"; x.em("H&R Block") }