[Haml] Add the ability to use CSS class/id shorthand with haml_tag.

doc-src/HAML_CHANGELOG.md

@@ -5,6 +5,22 @@
 
 ## 2.4.0 (Unreleased)
 
+### haml_tag improvement
+
+The {Haml::Helpers#haml_tag haml\_tag} helper can now take a string
+using the same class/id shorthand as in standard Haml code.
+Manually-specified class and id attributes are merged,
+again as in standard Haml code.
+For example:
+
+    haml_tag('#foo') #=> <div id='foo' />
+    haml_tag('.bar) #=> <div class='bar' />
+    haml_tag('span#foo.bar') #=> <span class='bar' id='foo' />
+    haml_tag('span#foo.bar', :class => 'abc') #=> <span class='abc bar' id='foo' />
+    haml_tag('span#foo.bar', :id => 'abc') #=> <span class='bar' id='abc_foo' />
+
+Cheers, [S. Burkhard](http://github.com/hasclass/).
+
 ### Object Reference Customization
 
 It's now possible to customize the name used for {file:HAML_REFERENCE.md#object_reference_ object reference}

lib/haml/helpers.rb

@@ -367,6 +367,11 @@ END
     # If the block is a Haml block or outputs text using \{#haml\_concat},
     # the text will be properly indented.
     #
+    # `name` can be a string using the standard Haml class/id shorthand
+    # (e.g. "span#foo.bar", "#foo").
+    # Just like standard Haml tags, these class and id values
+    # will be merged with manually-specified attributes.
+    #
     # `flags` is a list of symbol flags
     # like those that can be put at the end of a Haml tag
     # (`:/`, `:<`, and `:>`).
@@ -381,7 +386,7 @@ END
     #
     #     haml_tag :table do
     #       haml_tag :tr do
-    #         haml_tag :td, {:class => 'cell'} do
+    #         haml_tag 'td.cell' do
     #           haml_tag :strong, "strong!"
     #           haml_concat "data"
     #         end
@@ -417,13 +422,14 @@ END
     def haml_tag(name, *rest, &block)
       ret = ErrorReturn.new("haml_tag")
 
-      name = name.to_s
       text = rest.shift.to_s unless [Symbol, Hash, NilClass].any? {|t| rest.first.is_a? t}
       flags = []
       flags << rest.shift while rest.first.is_a? Symbol
+      name, attrs = merge_name_and_attributes(name.to_s, rest.shift || {})
+
       attributes = Haml::Precompiler.build_attributes(haml_buffer.html?,
                                                       haml_buffer.options[:attr_wrapper],
-                                                      rest.shift || {})
+                                                      attrs)
 
       if text.nil? && block.nil? && (haml_buffer.options[:autoclose].include?(name) || flags.include?(:/))
         haml_concat "<#{name}#{attributes} />"
@@ -512,6 +518,17 @@ END
 
     private
 
+    # Parses the tag name used for \{#haml\_tag}
+    # and merges it with the Ruby attributes hash.
+    def merge_name_and_attributes(name, attributes_hash = {})
+      # skip merging if no ids or classes found in name
+      return name, attributes_hash unless name =~ /^(.+?)?([\.#].*)$/
+
+      return $1 || "div", Buffer.merge_attrs(
+        Precompiler.parse_class_and_id($2),
+        Haml::Util.map_keys(attributes_hash) {|key| key.to_s})
+    end
+
     # Runs a block of code with the given buffer as the currently active buffer.
     #
     # @param buffer [Haml::Buffer] The Haml buffer to use temporarily

lib/haml/precompiler.rb

@@ -480,10 +480,12 @@ END
       @template_tabs -= 1
     end
 
+    # This is a class method so it can be accessed from {Haml::Helpers}.
+    #
     # Iterates through the classes and ids supplied through `.`
     # and `#` syntax, and returns a hash with them as attributes,
     # that can then be merged with another attributes hash.
-    def parse_class_and_id(list)
+    def self.parse_class_and_id(list)
       attributes = {}
       list.scan(/([#.])([-_a-zA-Z0-9]+)/) do |type, property|
         case type
@@ -733,7 +735,7 @@ END
 
       object_ref = "nil" if object_ref.nil? || @options[:suppress_eval]
 
-      attributes = parse_class_and_id(attributes)
+      attributes = Precompiler.parse_class_and_id(attributes)
       attributes_hashes.map! do |syntax, attributes_hash|
         if syntax == :old
           static_attributes = parse_static_hash(attributes_hash)

test/haml/helper_test.rb

@@ -125,6 +125,50 @@ HTML
 HAML
   end
 
+  def test_haml_tag_name_attribute_with_id
+    assert_equal("<p id='some_id'></p>\n", render("- haml_tag 'p#some_id'"))
+  end
+
+  def test_haml_tag_without_name_but_with_id
+    assert_equal("<div id='some_id'></div>\n", render("- haml_tag '#some_id'"))
+  end
+
+  def test_haml_tag_without_name_but_with_class
+    assert_equal("<div class='foo'></div>\n", render("- haml_tag '.foo'"))
+  end
+
+  def test_haml_tag_name_with_id_and_class
+    assert_equal("<p class='foo' id='some_id'></p>\n", render("- haml_tag 'p#some_id.foo'"))
+  end
+
+  def test_haml_tag_name_with_class
+    assert_equal("<p class='foo'></p>\n", render("- haml_tag 'p.foo'"))
+  end
+
+  def test_haml_tag_name_with_class_and_id
+    assert_equal("<p class='foo' id='some_id'></p>\n", render("- haml_tag 'p.foo#some_id'"))
+  end
+
+  def test_haml_tag_name_with_id_and_multiple_classes
+    assert_equal("<p class='foo bar' id='some_id'></p>\n", render("- haml_tag 'p#some_id.foo.bar'"))
+  end
+
+  def test_haml_tag_name_with_multiple_classes_and_id
+    assert_equal("<p class='foo bar' id='some_id'></p>\n", render("- haml_tag 'p.foo.bar#some_id'"))
+  end
+
+  def test_haml_tag_name_and_attribute_classes_merging
+    assert_equal("<p class='foo bar' id='some_id'></p>\n", render("- haml_tag 'p#some_id.foo', :class => 'bar'"))
+  end
+
+  def test_haml_tag_name_and_attribute_classes_merging
+    assert_equal("<p class='bar foo'></p>\n", render("- haml_tag 'p.foo', :class => 'bar'"))
+  end
+
+  def test_haml_tag_name_merges_id_and_attribute_id
+    assert_equal("<p id='foo_bar'></p>\n", render("- haml_tag 'p#foo', :id => 'bar'"))
+  end
+
   def test_haml_tag_attribute_html_escaping
     assert_equal("<p id='foo&amp;bar'>baz</p>\n", render("%p{:id => 'foo&bar'} baz", :escape_html => true))
   end