precompiler.rb in radiant-0.9.0.rc2

- old
+ new

@@ -1,50 +1,69 @@
 require 'strscan'
+require 'haml/shared'
 
 module Haml
+  # Handles the internal pre-compilation from Haml into Ruby code,
+  # which then runs the final creation of the HTML string.
   module Precompiler
+    include Haml::Util
+
     # Designates an XHTML/XML element.
+    # @private
     ELEMENT         = ?%
 
-    # Designates a <tt><div></tt> element with the given class.
+    # Designates a `<div>` element with the given class.
+    # @private
     DIV_CLASS       = ?.
 
-    # Designates a <tt><div></tt> element with the given id.
+    # Designates a `<div>` element with the given id.
+    # @private
     DIV_ID          = ?#
 
     # Designates an XHTML/XML comment.
+    # @private
     COMMENT         = ?/
 
     # Designates an XHTML doctype or script that is never HTML-escaped.
+    # @private
     DOCTYPE         = ?!
 
     # Designates script, the result of which is output.
+    # @private
     SCRIPT          = ?=
 
     # Designates script that is always HTML-escaped.
+    # @private
     SANITIZE        = ?&
 
     # Designates script, the result of which is flattened and output.
+    # @private
     FLAT_SCRIPT     = ?~
 
     # Designates script which is run but not output.
+    # @private
     SILENT_SCRIPT   = ?-
 
     # When following SILENT_SCRIPT, designates a comment that is not output.
+    # @private
     SILENT_COMMENT  = ?#
 
     # Designates a non-parsed line.
+    # @private
     ESCAPE          = ?\\
 
     # Designates a block of filtered text.
+    # @private
     FILTER          = ?:
 
     # Designates a non-parsed line. Not actually a character.
+    # @private
     PLAIN_TEXT      = -1
 
     # Keeps track of the ASCII values of the characters that begin a
     # specially-interpreted line.
+    # @private
     SPECIAL_CHARACTERS   = [
       ELEMENT,
       DIV_CLASS,
       DIV_ID,
       COMMENT,
@@ -57,115 +76,134 @@
       FILTER
     ]
 
     # The value of the character that designates that a line is part
     # of a multiline string.
+    # @private
     MULTILINE_CHAR_VALUE = ?|
 
-    # Characters that designate that a multiline string may be about
-    # to begin.
-    MULTILINE_STARTERS   = SPECIAL_CHARACTERS - [?/]
-
-    # Keywords that appear in the middle of a Ruby block with lowered
-    # indentation. If a block has been started using indentation,
-    # lowering the indentation  with one of these won't end the block.
+    # Regex to match keywords that appear in the middle of a Ruby block
+    # with lowered indentation.
+    # If a block has been started using indentation,
+    # lowering the indentation with one of these won't end the block.
     # For example:
     #
     #   - if foo
     #     %p yes!
     #   - else
     #     %p no!
     #
-    # The block is ended after <tt>%p no!</tt>, because <tt>else</tt>
+    # The block is ended after `%p no!`, because `else`
     # is a member of this array.
-    MID_BLOCK_KEYWORDS   = ['else', 'elsif', 'rescue', 'ensure', 'when']
+    # @private
+    MID_BLOCK_KEYWORD_REGEX = /^-\s*(#{%w[else elsif rescue ensure when end].join('|')})\b/
 
     # The Regex that matches a Doctype command.
-    DOCTYPE_REGEX = /(\d\.\d)?[\s]*([a-z]*)/i
+    # @private
+    DOCTYPE_REGEX = /(\d(?:\.\d)?)?[\s]*([a-z]*)/i
 
     # The Regex that matches a literal string or symbol value
-    LITERAL_VALUE_REGEX = /^\s*(:(\w*)|(('|")([^\\\#'"]*?)\4))\s*$/
+    # @private
+    LITERAL_VALUE_REGEX = /:(\w*)|(["'])((?![\\#]|\2).|\\.)*\2/
 
     private
 
     # Returns the precompiled string with the preamble and postamble
     def precompiled_with_ambles(local_names)
       preamble = <<END.gsub("\n", ";")
+begin
 extend Haml::Helpers
 _hamlout = @haml_buffer = Haml::Buffer.new(@haml_buffer, #{options_for_buffer.inspect})
 _erbout = _hamlout.buffer
 __in_erb_template = true
 END
       postamble = <<END.gsub("\n", ";")
+#{precompiled_method_return_value}
+ensure
 @haml_buffer = @haml_buffer.upper
-_erbout
+end
 END
-      preamble + locals_code(local_names) + @precompiled + postamble
+      preamble + locals_code(local_names) + precompiled + postamble
     end
 
+    # Returns the string used as the return value of the precompiled method.
+    # This method exists so it can be monkeypatched to return modified values.
+    def precompiled_method_return_value
+      "_erbout"
+    end
+
     def locals_code(names)
       names = names.keys if Hash == names
 
       names.map do |name|
         # Can't use || because someone might explicitly pass in false with a symbol
-        sym_local = "_haml_locals[#{name.to_sym.inspect}]" 
-        str_local = "_haml_locals[#{name.to_s.inspect}]" 
+        sym_local = "_haml_locals[#{name.to_sym.inspect}]"
+        str_local = "_haml_locals[#{name.to_s.inspect}]"
         "#{name} = #{sym_local}.nil? ? #{str_local} : #{sym_local}"
       end.join(';') + ';'
     end
 
-    Line = Struct.new(:text, :unstripped, :index, :spaces, :tabs)
+    # @private
+    class Line < Struct.new(:text, :unstripped, :full, :index, :precompiler, :eod)
+      alias_method :eod?, :eod
 
-    def precompile
-      @haml_comment = @dont_indent_next_line = @dont_tab_up_next_text = false
-      @indentation = nil
-      old_line = Line.new
-      @template.split(/\r\n|\r|\n/).each_with_index do |text, index|
-        @next_line = line = Line.new(text.strip, text.lstrip.chomp, index)
-        line.spaces, line.tabs = count_soft_tabs(text)
+      def tabs
+        line = self
+        @tabs ||= precompiler.instance_eval do
+          break 0 if line.text.empty? || !(whitespace = line.full[/^\s+/])
 
-        suppress_render = handle_multiline(old_line) unless flat?
+          if @indentation.nil?
+            @indentation = whitespace
 
-        if old_line.text.nil? || suppress_render
-          old_line = line
-          resolve_newlines
-          newline
-          next
-        end
+            if @indentation.include?(?\s) && @indentation.include?(?\t)
+              raise SyntaxError.new("Indentation can't use both tabs and spaces.", line.index)
+            end
 
-        process_indent(old_line) unless old_line.text.empty?
+            @flat_spaces = @indentation * @template_tabs if flat?
+            break 1
+          end
 
-        if line.text.empty? && !flat?
-          newline
-          next
+          tabs = whitespace.length / @indentation.length
+          break tabs if whitespace == @indentation * tabs
+          break @template_tabs if flat? && whitespace =~ /^#{@indentation * @template_tabs}/
+
+          raise SyntaxError.new(<<END.strip.gsub("\n", ' '), line.index)
+Inconsistent indentation: #{Haml::Shared.human_indentation whitespace, true} used for indentation,
+but the rest of the document was indented using #{Haml::Shared.human_indentation @indentation}.
+END
         end
+      end
+    end
 
+    def precompile
+      @haml_comment = @dont_indent_next_line = @dont_tab_up_next_text = false
+      @indentation = nil
+      @line = next_line
+      resolve_newlines
+      newline
+
+      raise SyntaxError.new("Indenting at the beginning of the document is illegal.", @line.index) if @line.tabs != 0
+
+      while next_line
+        process_indent(@line) unless @line.text.empty?
+
         if flat?
-          push_flat(old_line)
-          old_line = line
+          push_flat(@line)
+          @line = @next_line
           newline
           next
         end
 
-        if old_line.spaces != old_line.tabs * 2
-          raise SyntaxError.new(<<END.strip, old_line.index)
-#{old_line.spaces} space#{old_line.spaces == 1 ? ' was' : 's were'} used for indentation. Haml must be indented using two spaces.
-END
-        end
+        process_line(@line.text, @line.index) unless @line.text.empty? || @haml_comment
 
-        unless old_line.text.empty? || @haml_comment
-          process_line(old_line.text, old_line.index, line.tabs > old_line.tabs && !line.text.empty?)
+        if !flat? && @next_line.tabs - @line.tabs > 1
+          raise SyntaxError.new("The line was indented #{@next_line.tabs - @line.tabs} levels deeper than the previous line.", @next_line.index)
         end
-        resolve_newlines
 
-        if !flat? && line.tabs - old_line.tabs > 1
-          raise SyntaxError.new(<<END.strip, line.index)
-#{line.spaces} spaces were used for indentation. Haml must be indented using two spaces.
-END
-        end
-        old_line = line
-        newline
+        resolve_newlines unless @next_line.eod?
+        @line = @next_line
+        newline unless @next_line.eod?
       end
 
       # Close all the open tags
       close until @to_close_stack.empty?
       flush_merged_text
@@ -174,33 +212,36 @@
     # Processes and deals with lowering indentation.
     def process_indent(line)
       return unless line.tabs <= @template_tabs && @template_tabs > 0
 
       to_close = @template_tabs - line.tabs
-      to_close.times { |i| close unless to_close - 1 - i == 0 && mid_block_keyword?(line.text) }
+      to_close.times {|i| close unless to_close - 1 - i == 0 && mid_block_keyword?(line.text)}
     end
 
     # Processes a single line of Haml.
     #
     # This method doesn't return anything; it simply processes the line and
-    # adds the appropriate code to <tt>@precompiled</tt>.
-    def process_line(text, index, block_opened)
-      @block_opened = block_opened
+    # adds the appropriate code to `@precompiled`.
+    def process_line(text, index)
       @index = index + 1
 
       case text[0]
-      when DIV_CLASS, DIV_ID; render_div(text)
+      when DIV_CLASS; render_div(text)
+      when DIV_ID
+        return push_plain(text) if text[1] == ?{
+        render_div(text)
       when ELEMENT; render_tag(text)
       when COMMENT; render_comment(text[1..-1].strip)
       when SANITIZE
-        return push_script(unescape_interpolation(text[3..-1].strip), false, false, false, true) if text[1..2] == "=="
-        return push_script(text[2..-1].strip, false, false, false, true) if text[1] == SCRIPT
+        return push_plain(text[3..-1].strip, :escape_html => true) if text[1..2] == "=="
+        return push_script(text[2..-1].strip, :escape_html => true) if text[1] == SCRIPT
+        return push_flat_script(text[2..-1].strip, :escape_html => true) if text[1] == FLAT_SCRIPT
+        return push_plain(text[1..-1].strip, :escape_html => true) if text[1] == ?\s
         push_plain text
       when SCRIPT
-        return push_script(unescape_interpolation(text[2..-1].strip), false) if text[1] == SCRIPT
-        return push_script(text[1..-1], false, false, false, true) if options[:escape_html]
-        push_script(text[1..-1], false)
+        return push_plain(text[2..-1].strip) if text[1] == SCRIPT
+        push_script(text[1..-1])
       when FLAT_SCRIPT; push_flat_script(text[1..-1])
       when SILENT_SCRIPT
         return start_haml_comment if text[1] == SILENT_COMMENT
 
         raise SyntaxError.new(<<END.rstrip, index) if text[1..-1].strip == "end"
@@ -212,192 +253,208 @@
 END
 
         push_silent(text[1..-1], true)
         newline_now
 
-        case_stmt = text[1..-1].split(' ', 2)[0] == "case"
-        block = @block_opened && !mid_block_keyword?(text)
-        push_and_tabulate([:script]) if block || case_stmt
-        push_and_tabulate(nil)       if block && case_stmt
+        # Handle stuff like - end.join("|")
+        @to_close_stack.last << false if text =~ /^-\s*end\b/ && !block_opened?
+
+        case_stmt = text =~ /^-\s*case\b/
+        keyword = mid_block_keyword?(text)
+        block = block_opened? && !keyword
+
+        # It's important to preserve tabulation modification for keywords
+        # that involve choosing between posible blocks of code.
+        if %w[else elsif when].include?(keyword)
+          # @to_close_stack may not have a :script on top
+          # when the preceding "- if" has nothing nested
+          if @to_close_stack.last && @to_close_stack.last.first == :script
+            @dont_indent_next_line, @dont_tab_up_next_text = @to_close_stack.last[1..2]
+          else
+            push_and_tabulate([:script, @dont_indent_next_line, @dont_tab_up_next_text])
+          end
+
+          # when is unusual in that either it will be indented twice,
+          # or the case won't have created its own indentation
+          if keyword == "when"
+            push_and_tabulate([:script, @dont_indent_next_line, @dont_tab_up_next_text, false])
+          end
+        elsif block || case_stmt
+          push_and_tabulate([:script, @dont_indent_next_line, @dont_tab_up_next_text])
+        elsif block && case_stmt
+          push_and_tabulate([:script, @dont_indent_next_line, @dont_tab_up_next_text])
+        end
       when FILTER; start_filtered(text[1..-1].downcase)
       when DOCTYPE
         return render_doctype(text) if text[0...3] == '!!!'
-        return push_script(unescape_interpolation(text[3..-1].strip), false) if text[1..2] == "=="
-        return push_script(text[2..-1].strip, false) if text[1] == SCRIPT
+        return push_plain(text[3..-1].strip, :escape_html => false) if text[1..2] == "=="
+        return push_script(text[2..-1].strip, :escape_html => false) if text[1] == SCRIPT
+        return push_flat_script(text[2..-1].strip, :escape_html => false) if text[1] == FLAT_SCRIPT
+        return push_plain(text[1..-1].strip, :escape_html => false) if text[1] == ?\s
         push_plain text
       when ESCAPE; push_plain text[1..-1]
       else push_plain text
       end
     end
 
-    # Returns whether or not the text is a silent script text with one
-    # of Ruby's mid-block keywords.
+    # If the text is a silent script text with one of Ruby's mid-block keywords,
+    # returns the name of that keyword.
+    # Otherwise, returns nil.
     def mid_block_keyword?(text)
-      text.length > 2 && text[0] == SILENT_SCRIPT && MID_BLOCK_KEYWORDS.include?(text[1..-1].split[0])
+      text[MID_BLOCK_KEYWORD_REGEX, 1]
     end
 
-    # Deals with all the logic of figuring out whether a given line is
-    # the beginning, continuation, or end of a multiline sequence.
-    #
-    # This returns whether or not the line should be
-    # rendered normally.
-    def handle_multiline(line)
-      text = line.text
-
-      # A multiline string is active, and is being continued
-      if is_multiline?(text) && @multiline
-        @multiline.text << text[0...-1]
-        return true
-      end
-
-      # A multiline string has just been activated, start adding the lines
-      if is_multiline?(text) && (MULTILINE_STARTERS.include? text[0])
-        @multiline = Line.new text[0...-1], nil, line.index, nil, line.tabs
-        process_indent(line)
-        return true
-      end
-
-      # A multiline string has just ended, make line into the result
-      if @multiline && !line.text.empty?
-        process_line(@multiline.text, @multiline.index, line.tabs > @multiline.tabs)
-        @multiline = nil
-      end
-
-      return false
-    end
-
-    # Checks whether or not +line+ is in a multiline sequence.
-    def is_multiline?(text)
-      text && text.length > 1 && text[-1] == MULTILINE_CHAR_VALUE && text[-2] == ?\s
-    end
-
-    # Evaluates <tt>text</tt> in the context of the scope object, but
+    # Evaluates `text` in the context of the scope object, but
     # does not output the result.
     def push_silent(text, can_suppress = false)
       flush_merged_text
       return if can_suppress && options[:suppress_eval]
       @precompiled << "#{text};"
     end
 
-    # Adds <tt>text</tt> to <tt>@buffer</tt> with appropriate tabulation
+    # Adds `text` to `@buffer` with appropriate tabulation
     # without parsing it.
     def push_merged_text(text, tab_change = 0, indent = true)
-      @merged_text  << (!indent || @dont_indent_next_line || @options[:ugly] ? text : "#{'  ' * @output_tabs}#{text}")
+      text = !indent || @dont_indent_next_line || @options[:ugly] ? text : "#{'  ' * @output_tabs}#{text}"
+      @to_merge << [:text, text, tab_change]
       @dont_indent_next_line = false
-      @tab_change   += tab_change
     end
 
-    # Concatenate <tt>text</tt> to <tt>@buffer</tt> without tabulation.
+    # Concatenate `text` to `@buffer` without tabulation.
     def concat_merged_text(text)
-      @merged_text  << text
+      @to_merge << [:text, text, 0]
     end
 
     def push_text(text, tab_change = 0)
       push_merged_text("#{text}\n", tab_change)
     end
 
     def flush_merged_text
-      return if @merged_text.empty?
+      return if @to_merge.empty?
 
-      @precompiled  << "_hamlout.push_text(#{@merged_text.dump}"
-      @precompiled  << ", #{@dont_tab_up_next_text.inspect}" if @dont_tab_up_next_text || @tab_change != 0
-      @precompiled  << ", #{@tab_change}" if @tab_change != 0
-      @precompiled  << ");"
-      @merged_text   = ''
+      text, tab_change = @to_merge.inject(["", 0]) do |(str, mtabs), (type, val, tabs)|
+        case type
+        when :text
+          [str << val.inspect[1...-1], mtabs + tabs]
+        when :script
+          if mtabs != 0 && !@options[:ugly]
+            val = "_hamlout.adjust_tabs(#{mtabs}); " + val
+          end
+          [str << "\#{#{val}}", 0]
+        else
+          raise SyntaxError.new("[HAML BUG] Undefined entry in Haml::Precompiler@to_merge.")
+        end
+      end
+
+      @precompiled <<
+        if @options[:ugly]
+          "_hamlout.buffer << \"#{text}\";"
+        else
+          "_hamlout.push_text(\"#{text}\", #{tab_change}, #{@dont_tab_up_next_text.inspect});"
+        end
+      @to_merge = []
       @dont_tab_up_next_text = false
-      @tab_change    = 0
     end
 
     # Renders a block of text as plain text.
     # Also checks for an illegally opened block.
-    def push_plain(text)
-      if @block_opened
+    def push_plain(text, options = {})
+      if block_opened?
         raise SyntaxError.new("Illegal nesting: nesting within plain text is illegal.", @next_line.index)
       end
 
-      push_text text
+      if contains_interpolation?(text)
+        options[:escape_html] = self.options[:escape_html] if options[:escape_html].nil?
+        push_script(
+          unescape_interpolation(text, :escape_html => options[:escape_html]),
+          :escape_html => false)
+      else
+        push_text text
+      end
     end
 
-    # Adds +text+ to <tt>@buffer</tt> while flattening text.
+    # Adds +text+ to `@buffer` while flattening text.
     def push_flat(line)
-      tabulation = line.spaces - @flat_spaces
-      tabulation = tabulation > -1 ? tabulation : 0
-      @filter_buffer << "#{' ' * tabulation}#{line.unstripped}\n"
+      text = line.full.dup
+      text = "" unless text.gsub!(/^#{@flat_spaces}/, '')
+      @filter_buffer << "#{text}\n"
     end
 
-    # Causes <tt>text</tt> to be evaluated in the context of
-    # the scope object and the result to be added to <tt>@buffer</tt>.
+    # Causes `text` to be evaluated in the context of
+    # the scope object and the result to be added to `@buffer`.
     #
-    # If <tt>preserve_script</tt> is true, Haml::Helpers#find_and_flatten is run on
-    # the result before it is added to <tt>@buffer</tt>
-    def push_script(text, preserve_script, in_tag = false, preserve_tag = false,
-                    escape_html = false, nuke_inner_whitespace = false)
+    # If `opts[:preserve_script]` is true, Haml::Helpers#find_and_flatten is run on
+    # the result before it is added to `@buffer`
+    def push_script(text, opts = {})
+      raise SyntaxError.new("There's no Ruby code for = to evaluate.") if text.empty?
+      return if options[:suppress_eval]
+      opts[:escape_html] = options[:escape_html] if opts[:escape_html].nil?
+
+      args = %w[preserve_script in_tag preserve_tag escape_html nuke_inner_whitespace]
+      args.map! {|name| opts[name.to_sym]}
+      args << !block_opened? << @options[:ugly]
+
+      no_format = @options[:ugly] &&
+        !(opts[:preserve_script] || opts[:preserve_tag] || opts[:escape_html])
+      output_temp = "(haml_very_temp = haml_temp; haml_temp = nil; haml_very_temp)"
+      out = "_hamlout.#{static_method_name(:format_script, *args)}(#{output_temp});"
+
       # Prerender tabulation unless we're in a tag
-      push_merged_text '' unless in_tag
+      push_merged_text '' unless opts[:in_tag]
 
+      unless block_opened?
+        @to_merge << [:script, no_format ? "#{text}\n" : "haml_temp = #{text}\n#{out}"]
+        concat_merged_text("\n") unless opts[:in_tag] || opts[:nuke_inner_whitespace]
+        @newlines -= 1
+        return
+      end
+
       flush_merged_text
-      return if options[:suppress_eval]
 
-      raise SyntaxError.new("There's no Ruby code for = to evaluate.") if text.empty?
-
       push_silent "haml_temp = #{text}"
       newline_now
-      args = [preserve_script, in_tag, preserve_tag,
-              escape_html, nuke_inner_whitespace].map { |a| a.inspect }.join(', ')
-      out = "haml_temp = _hamlout.push_script(haml_temp, #{args});"
-      if @block_opened
-        push_and_tabulate([:loud, out])
-      else
-        @precompiled << out
-      end
+      push_and_tabulate([:loud, "_hamlout.buffer << #{no_format ? "#{output_temp}.to_s;" : out}",
+        !(opts[:in_tag] || opts[:nuke_inner_whitespace] || @options[:ugly])])
     end
 
-    # Causes <tt>text</tt> to be evaluated, and Haml::Helpers#find_and_flatten
+    # Causes `text` to be evaluated, and Haml::Helpers#find_and_flatten
     # to be run on it afterwards.
-    def push_flat_script(text)
+    def push_flat_script(text, options = {})
       flush_merged_text
 
       raise SyntaxError.new("There's no Ruby code for ~ to evaluate.") if text.empty?
-      push_script(text, true)
+      push_script(text, options.merge(:preserve_script => true))
     end
 
     def start_haml_comment
-      return unless @block_opened
+      return unless block_opened?
 
       @haml_comment = true
       push_and_tabulate([:haml_comment])
     end
 
-    # Closes the most recent item in <tt>@to_close_stack</tt>.
+    # Closes the most recent item in `@to_close_stack`.
     def close
-      tag, value = @to_close_stack.pop
-      case tag
-      when :script; close_block
-      when :comment; close_comment value
-      when :element; close_tag value
-      when :loud; close_loud value
-      when :filtered; close_filtered value
-      when :haml_comment; close_haml_comment
-      when nil; close_nil
-      end
+      tag, *rest = @to_close_stack.pop
+      send("close_#{tag}", *rest)
     end
 
-    # Puts a line in <tt>@precompiled</tt> that will add the closing tag of
+    # Puts a line in `@precompiled` that will add the closing tag of
     # the most recently opened tag.
-    def close_tag(value)
+    def close_element(value)
       tag, nuke_outer_whitespace, nuke_inner_whitespace = value
       @output_tabs -= 1 unless nuke_inner_whitespace
       @template_tabs -= 1
       rstrip_buffer! if nuke_inner_whitespace
       push_merged_text("</#{tag}>" + (nuke_outer_whitespace ? "" : "\n"),
                        nuke_inner_whitespace ? 0 : -1, !nuke_inner_whitespace)
       @dont_indent_next_line = nuke_outer_whitespace
     end
 
     # Closes a Ruby block.
-    def close_block
-      push_silent "end", true
+    def close_script(_1, _2, push_end = true)
+      push_silent("end", true) if push_end
       @template_tabs -= 1
     end
 
     # Closes a comment.
     def close_comment(has_conditional)
@@ -406,35 +463,37 @@
       close_tag = has_conditional ? "<![endif]-->" : "-->"
       push_text(close_tag, -1)
     end
 
     # Closes a loud Ruby block.
-    def close_loud(command)
-      push_silent 'end', true
+    def close_loud(command, add_newline, push_end = true)
+      push_silent('end', true) if push_end
       @precompiled << command
       @template_tabs -= 1
+      concat_merged_text("\n") if add_newline
     end
 
     # Closes a filtered block.
     def close_filtered(filter)
-      @flat_spaces = -1
       filter.internal_compile(self, @filter_buffer)
+      @flat = false
+      @flat_spaces = nil
       @filter_buffer = nil
       @template_tabs -= 1
     end
 
     def close_haml_comment
       @haml_comment = false
       @template_tabs -= 1
     end
 
-    def close_nil
+    def close_nil(*args)
       @template_tabs -= 1
     end
 
-    # Iterates through the classes and ids supplied through <tt>.</tt>
-    # and <tt>#</tt> syntax, and returns a hash with them as attributes,
+    # 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)
       attributes = {}
       list.scan(/([#.])([-_a-zA-Z0-9]+)/) do |type, property|
         case type
@@ -449,34 +508,22 @@
         end
       end
       attributes
     end
 
-    def parse_literal_value(text)
-      return nil unless text
-      text.match(LITERAL_VALUE_REGEX)
-
-      # $2 holds the value matched by a symbol, but is nil for a string match
-      # $5 holds the value matched by a string
-      $2 || $5
-    end
-
     def parse_static_hash(text)
-      return {} unless text
-
       attributes = {}
-      text.split(',').each do |attrib|
-        key, value, more = attrib.split('=>')
-
-        # Make sure the key and value and only the key and value exist
-        # Otherwise, it's too complicated or dynamic and we'll defer it to the actual Ruby parser
-        key = parse_literal_value key
-        value = parse_literal_value value
-        return nil if more || key.nil? || value.nil?
-
-        attributes[key] = value
+      scanner = StringScanner.new(text)
+      scanner.scan(/\s+/)
+      until scanner.eos?
+        return unless key = scanner.scan(LITERAL_VALUE_REGEX)
+        return unless scanner.scan(/\s*=>\s*/)
+        return unless value = scanner.scan(LITERAL_VALUE_REGEX)
+        return unless scanner.scan(/\s*(?:,|$)\s*/)
+        attributes[eval(key).to_s] = eval(value).to_s
       end
+      text.count("\n").times { newline }
       attributes
     end
 
     # This is a class method so it can be accessed from Buffer.
     def self.build_attributes(is_html, attr_wrapper, attributes = {})
@@ -516,149 +563,284 @@
 
     # Parses a line into tag_name, attributes, attributes_hash, object_ref, action, value
     def parse_tag(line)
       raise SyntaxError.new("Invalid tag: \"#{line}\".") unless match = line.scan(/%([-:\w]+)([-\w\.\#]*)(.*)/)[0]
       tag_name, attributes, rest = match
-      attributes_hash, rest = parse_attributes(rest) if rest[0] == ?{
+      new_attributes_hash = old_attributes_hash = last_line = object_ref = nil
+      attributes_hashes = []
+      while rest
+        case rest[0]
+        when ?{
+          break if old_attributes_hash
+          old_attributes_hash, rest, last_line = parse_old_attributes(rest)
+          attributes_hashes << [:old, old_attributes_hash]
+        when ?(
+          break if new_attributes_hash
+          new_attributes_hash, rest, last_line = parse_new_attributes(rest)
+          attributes_hashes << [:new, new_attributes_hash]
+        when ?[
+          break if object_ref
+          object_ref, rest = balance(rest, ?[, ?])
+        else; break
+        end
+      end
+
       if rest
-        object_ref, rest = balance(rest, ?[, ?]) if rest[0] == ?[
-        attributes_hash, rest = parse_attributes(rest) if rest[0] == ?{ && attributes_hash.nil?
         nuke_whitespace, action, value = rest.scan(/(<>|><|[><])?([=\/\~&!])?(.*)?/)[0]
         nuke_whitespace ||= ''
         nuke_outer_whitespace = nuke_whitespace.include? '>'
         nuke_inner_whitespace = nuke_whitespace.include? '<'
       end
+
       value = value.to_s.strip
-      [tag_name, attributes, attributes_hash, object_ref, nuke_outer_whitespace,
-       nuke_inner_whitespace, action, value]
+      [tag_name, attributes, attributes_hashes, object_ref, nuke_outer_whitespace,
+       nuke_inner_whitespace, action, value, last_line || @index]
     end
 
-    def parse_attributes(line)
-      scanner = StringScanner.new(line)
-      attributes_hash, rest = balance(scanner, ?{, ?})
+    def parse_old_attributes(line)
+      line = line.dup
+      last_line = @index
+
+      begin
+        attributes_hash, rest = balance(line, ?{, ?})
+      rescue SyntaxError => e
+        if line.strip[-1] == ?, && e.message == "Unbalanced brackets."
+          line << "\n" << @next_line.text
+          last_line += 1
+          next_line
+          retry
+        end
+
+        raise e
+      end
+
       attributes_hash = attributes_hash[1...-1] if attributes_hash
-      return attributes_hash, rest
+      return attributes_hash, rest, last_line
     end
 
+    def parse_new_attributes(line)
+      line = line.dup
+      scanner = StringScanner.new(line)
+      last_line = @index
+      attributes = {}
+
+      scanner.scan(/\(\s*/)
+      loop do
+        name, value = parse_new_attribute(scanner)
+        break if name.nil?
+
+        if name == false
+          text = (Haml::Shared.balance(line, ?(, ?)) || [line]).first
+          raise Haml::SyntaxError.new("Invalid attribute list: #{text.inspect}.", last_line - 1)
+        end
+        attributes[name] = value
+        scanner.scan(/\s*/)
+
+        if scanner.eos?
+          line << " " << @next_line.text
+          last_line += 1
+          next_line
+          scanner.scan(/\s*/)
+        end
+      end
+
+      static_attributes = {}
+      dynamic_attributes = "{"
+      attributes.each do |name, (type, val)|
+        if type == :static
+          static_attributes[name] = val
+        else
+          dynamic_attributes << name.inspect << " => " << val << ","
+        end
+      end
+      dynamic_attributes << "}"
+      dynamic_attributes = nil if dynamic_attributes == "{}"
+
+      return [static_attributes, dynamic_attributes], scanner.rest, last_line
+    end
+
+    def parse_new_attribute(scanner)
+      unless name = scanner.scan(/[-:\w]+/)
+        return if scanner.scan(/\)/)
+        return false
+      end
+
+      scanner.scan(/\s*/)
+      return name, [:static, true] unless scanner.scan(/=/) #/end
+
+      scanner.scan(/\s*/)
+      unless quote = scanner.scan(/["']/)
+        return false unless var = scanner.scan(/(@@?|\$)?\w+/)
+        return name, [:dynamic, var]
+      end
+
+      re = /((?:\\.|\#(?!\{)|[^#{quote}\\#])*)(#{quote}|#\{)/
+      content = []
+      loop do
+        return false unless scanner.scan(re)
+        content << [:str, scanner[1].gsub(/\\(.)/, '\1')]
+        break if scanner[2] == quote
+        content << [:ruby, balance(scanner, ?{, ?}, 1).first[0...-1]]
+      end
+
+      return name, [:static, content.first[1]] if content.size == 1
+      return name, [:dynamic,
+        '"' + content.map {|(t, v)| t == :str ? v.inspect[1...-1] : "\#{#{v}}"}.join + '"']
+    end
+
     # Parses a line that will render as an XHTML tag, and adds the code that will
-    # render that tag to <tt>@precompiled</tt>.
+    # render that tag to `@precompiled`.
     def render_tag(line)
-      tag_name, attributes, attributes_hash, object_ref, nuke_outer_whitespace,
-        nuke_inner_whitespace, action, value = parse_tag(line)
+      tag_name, attributes, attributes_hashes, object_ref, nuke_outer_whitespace,
+        nuke_inner_whitespace, action, value, last_line = parse_tag(line)
 
       raise SyntaxError.new("Illegal element: classes and ids must have values.") if attributes =~ /[\.#](\.|#|\z)/
 
       # Get rid of whitespace outside of the tag if we need to
       rstrip_buffer! if nuke_outer_whitespace
 
       preserve_tag = options[:preserve].include?(tag_name)
       nuke_inner_whitespace ||= preserve_tag
       preserve_tag &&= !options[:ugly]
 
+      escape_html = (action == '&' || (action != '!' && @options[:escape_html]))
+
       case action
       when '/'; self_closing = true
       when '~'; parse = preserve_script = true
       when '='
         parse = true
-        value = unescape_interpolation(value[1..-1].strip) if value[0] == ?=
-      when '&', '!'
         if value[0] == ?=
+          value = unescape_interpolation(value[1..-1].strip, :escape_html => escape_html)
+          escape_html = false
+        end
+      when '&', '!'
+        if value[0] == ?= || value[0] == ?~
           parse = true
-          value = (value[1] == ?= ? unescape_interpolation(value[2..-1].strip) : value[1..-1].strip)
+          preserve_script = (value[0] == ?~)
+          if value[1] == ?=
+            value = unescape_interpolation(value[2..-1].strip, :escape_html => escape_html)
+            escape_html = false
+          else
+            value = value[1..-1].strip
+          end
+        elsif contains_interpolation?(value)
+          value = unescape_interpolation(value, :escape_html => escape_html)
+          parse = true
+          escape_html = false
         end
+      else
+        if contains_interpolation?(value)
+          value = unescape_interpolation(value, :escape_html => escape_html)
+          parse = true
+          escape_html = false
+        end
       end
 
       if parse && @options[:suppress_eval]
         parse = false
         value = ''
       end
 
-      escape_html = (action == '&' || (action != '!' && @options[:escape_html]))
-
       object_ref = "nil" if object_ref.nil? || @options[:suppress_eval]
 
-      static_attributes = parse_static_hash(attributes_hash) # Try pre-compiling a static attributes hash
-      attributes_hash = nil if static_attributes || @options[:suppress_eval]
       attributes = parse_class_and_id(attributes)
-      Buffer.merge_attrs(attributes, static_attributes) if static_attributes
+      attributes_hashes.map! do |syntax, attributes_hash|
+        if syntax == :old
+          static_attributes = parse_static_hash(attributes_hash)
+          attributes_hash = nil if static_attributes || @options[:suppress_eval]
+        else
+          static_attributes, attributes_hash = attributes_hash
+        end
+        Buffer.merge_attrs(attributes, static_attributes) if static_attributes
+        attributes_hash
+      end.compact!
 
-      raise SyntaxError.new("Illegal nesting: nesting within a self-closing tag is illegal.", @next_line.index) if @block_opened && self_closing
-      raise SyntaxError.new("Illegal nesting: content can't be both given on the same line as %#{tag_name} and nested within it.", @next_line.index) if @block_opened && !value.empty?
-      raise SyntaxError.new("There's no Ruby code for #{action} to evaluate.") if parse && value.empty?
-      raise SyntaxError.new("Self-closing tags can't have content.") if self_closing && !value.empty?
+      raise SyntaxError.new("Illegal nesting: nesting within a self-closing tag is illegal.", @next_line.index) if block_opened? && self_closing
+      raise SyntaxError.new("Illegal nesting: content can't be both given on the same line as %#{tag_name} and nested within it.", @next_line.index) if block_opened? && !value.empty?
+      raise SyntaxError.new("There's no Ruby code for #{action} to evaluate.", last_line - 1) if parse && value.empty?
+      raise SyntaxError.new("Self-closing tags can't have content.", last_line - 1) if self_closing && !value.empty?
 
-      self_closing ||= !!( !@block_opened && value.empty? && @options[:autoclose].include?(tag_name) )
+      self_closing ||= !!( !block_opened? && value.empty? && @options[:autoclose].include?(tag_name) )
+      value = nil if value.empty? && (block_opened? || self_closing)
 
       dont_indent_next_line =
-        (nuke_outer_whitespace && !@block_opened) ||
-        (nuke_inner_whitespace && @block_opened)
+        (nuke_outer_whitespace && !block_opened?) ||
+        (nuke_inner_whitespace && block_opened?)
 
       # Check if we can render the tag directly to text and not process it in the buffer
-      if object_ref == "nil" && attributes_hash.nil? && !preserve_script
-        tag_closed = !@block_opened && !self_closing && !parse
+      if object_ref == "nil" && attributes_hashes.empty? && !preserve_script
+        tag_closed = !block_opened? && !self_closing && !parse
 
         open_tag  = prerender_tag(tag_name, self_closing, attributes)
         if tag_closed
           open_tag << "#{value}</#{tag_name}>"
           open_tag << "\n" unless nuke_outer_whitespace
         else
           open_tag << "\n" unless parse || nuke_inner_whitespace || (self_closing && nuke_outer_whitespace)
         end
-        
+
         push_merged_text(open_tag, tag_closed || self_closing || nuke_inner_whitespace ? 0 : 1,
                          !nuke_outer_whitespace)
 
         @dont_indent_next_line = dont_indent_next_line
         return if tag_closed
       else
         flush_merged_text
-        content = value.empty? || parse ? 'nil' : value.dump
-        attributes_hash = ', ' + attributes_hash if attributes_hash
-        args = [tag_name, self_closing, !@block_opened, preserve_tag, escape_html,
+        content = parse ? 'nil' : value.inspect
+        if attributes_hashes.empty?
+          attributes_hashes = ''
+        elsif attributes_hashes.size == 1
+          attributes_hashes = ", #{attributes_hashes.first}"
+        else
+          attributes_hashes = ", (#{attributes_hashes.join(").merge(")})"
+        end
+
+        args = [tag_name, self_closing, !block_opened?, preserve_tag, escape_html,
                 attributes, nuke_outer_whitespace, nuke_inner_whitespace
                ].map { |v| v.inspect }.join(', ')
-        push_silent "_hamlout.open_tag(#{args}, #{object_ref}, #{content}#{attributes_hash})"
+        push_silent "_hamlout.open_tag(#{args}, #{object_ref}, #{content}#{attributes_hashes})"
         @dont_tab_up_next_text = @dont_indent_next_line = dont_indent_next_line
       end
 
       return if self_closing
 
-      if value.empty?
+      if value.nil?
         push_and_tabulate([:element, [tag_name, nuke_outer_whitespace, nuke_inner_whitespace]])
         @output_tabs += 1 unless nuke_inner_whitespace
         return
       end
 
       if parse
-        flush_merged_text
-        push_script(value, preserve_script, true, preserve_tag, escape_html, nuke_inner_whitespace)
-        @dont_tab_up_next_text = true
+        push_script(value, :preserve_script => preserve_script, :in_tag => true,
+          :preserve_tag => preserve_tag, :escape_html => escape_html,
+          :nuke_inner_whitespace => nuke_inner_whitespace)
         concat_merged_text("</#{tag_name}>" + (nuke_outer_whitespace ? "" : "\n"))
       end
     end
 
     # Renders a line that creates an XHTML tag and has an implicit div because of
-    # <tt>.</tt> or <tt>#</tt>.
+    # `.` or `#`.
     def render_div(line)
       render_tag('%div' + line)
     end
 
     # Renders an XHTML comment.
     def render_comment(line)
       conditional, line = balance(line, ?[, ?]) if line[0] == ?[
       line.strip!
       conditional << ">" if conditional
 
-      if @block_opened && !line.empty?
+      if block_opened? && !line.empty?
         raise SyntaxError.new('Illegal nesting: nesting within a tag that already has content is illegal.', @next_line.index)
       end
 
-      open = "<!--#{conditional} "
+      open = "<!--#{conditional}"
 
       # Render it statically if possible
       unless line.empty?
-        return push_text("#{open}#{line} #{conditional ? "<![endif]-->" : "-->"}")
+        return push_text("#{open} #{line} #{conditional ? "<![endif]-->" : "-->"}")
       end
 
       push_text(open, 1)
       @output_tabs += 1
       push_and_tabulate([:comment, !conditional.nil?])
@@ -668,11 +850,11 @@
       end
     end
 
     # Renders an XHTML doctype or XML shebang.
     def render_doctype(line)
-      raise SyntaxError.new("Illegal nesting: nesting within a header command is illegal.", @next_line.index) if @block_opened
+      raise SyntaxError.new("Illegal nesting: nesting within a header command is illegal.", @next_line.index) if block_opened?
       doctype = text_for_doctype(line)
       push_text doctype if doctype
     end
 
     def text_for_doctype(text)
@@ -689,10 +871,12 @@
         version, type = text.scan(DOCTYPE_REGEX)[0]
 
         if xhtml?
           if version == "1.1"
             '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">'
+          elsif version == "5"
+            '<!DOCTYPE html>'
           else
             case type
             when "strict";   '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">'
             when "frameset"; '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Frameset//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd">'
             when "mobile";   '<!DOCTYPE html PUBLIC "-//WAPFORUM//DTD XHTML Mobile 1.2//EN" "http://www.openmobilealliance.org/tech/DTD/xhtml-mobile12.dtd">'
@@ -715,73 +899,125 @@
     def start_filtered(name)
       raise Error.new("Invalid filter name \":#{name}\".") unless name =~ /^\w+$/
       raise Error.new("Filter \"#{name}\" is not defined.") unless filter = Filters.defined[name]
 
       push_and_tabulate([:filtered, filter])
-      @flat_spaces = @template_tabs * 2
+      @flat = true
       @filter_buffer = String.new
-      @block_opened = false
+
+      # If we don't know the indentation by now, it'll be set in Line#tabs
+      @flat_spaces = @indentation * @template_tabs if @indentation
     end
 
-    def contains_interpolation?(str)
-      str.include?('#{')
+    def raw_next_line
+      text = @template.shift
+      return unless text
+
+      index = @template_index
+      @template_index += 1
+
+      return text, index
     end
 
-    def unescape_interpolation(str)
-      scan = StringScanner.new(str.dump)
-      str = ''
+    def next_line
+      text, index = raw_next_line
+      return unless text
 
-      while scan.scan(/(.*?)(\\+)\#\{/)
-        escapes = (scan[2].size - 1) / 2
-        str << scan.matched[0...-3 - escapes]
-        if escapes % 2 == 1
-          str << '#{'
+      # :eod is a special end-of-document marker
+      line =
+        if text == :eod
+          Line.new '-#', '-#', '-#', index, self, true
         else
-          # Use eval to get rid of string escapes
-          str << '#{' + eval('"' + balance(scan, ?{, ?}, 1)[0][0...-1] + '"') + "}"
+          Line.new text.strip, text.lstrip.chomp, text, index, self, false
         end
+
+      # `flat?' here is a little outdated,
+      # so we have to manually check if either the previous or current line
+      # closes the flat block,
+      # as well as whether a new block is opened
+      @line.tabs if @line
+      unless (flat? && !closes_flat?(line) && !closes_flat?(@line)) ||
+          (@line && @line.text[0] == ?: && line.full =~ %r[^#{@line.full[/^\s+/]}\s])
+        if line.text.empty?
+          newline
+          return next_line
+        end
+
+        handle_multiline(line)
       end
 
-      str + scan.rest
+      @next_line = line
     end
 
-    def balance(scanner, start, finish, count = 0)
-      str = ''
-      scanner = StringScanner.new(scanner) unless scanner.is_a? StringScanner
-      regexp = Regexp.new("(.*?)[\\#{start.chr}\\#{finish.chr}]")
-      while scanner.scan(regexp)
-        str << scanner.matched
-        count += 1 if scanner.matched[-1] == start
-        count -= 1 if scanner.matched[-1] == finish
-        return [str.strip, scanner.rest] if count == 0
+    def closes_flat?(line)
+      line && !line.text.empty? && line.full !~ /^#{@flat_spaces}/
+    end
+
+    def un_next_line(line)
+      @template.unshift line
+      @template_index -= 1
+    end
+
+    def handle_multiline(line)
+      if is_multiline?(line.text)
+        line.text.slice!(-1)
+        while new_line = raw_next_line.first
+          break if new_line == :eod
+          newline and next if new_line.strip.empty?
+          break unless is_multiline?(new_line.strip)
+          line.text << new_line.strip[0...-1]
+          newline
+        end
+        un_next_line new_line
+        resolve_newlines
       end
+    end
 
-      raise SyntaxError.new("Unbalanced brackets.")
+    # Checks whether or not +line+ is in a multiline sequence.
+    def is_multiline?(text)
+      text && text.length > 1 && text[-1] == MULTILINE_CHAR_VALUE && text[-2] == ?\s
     end
 
-    # Counts the tabulation of a line.
-    def count_soft_tabs(line)
-      spaces = line.index(/([^ ]|$)/)
-      if line[spaces] == ?\t
-        return 0, 0 if line.strip.empty?
-        raise SyntaxError.new(<<END.strip, @next_line.index)
-A tab character was used for indentation. Haml must be indented using two spaces.
-Are you sure you have soft tabs enabled in your editor?
-END
+    def contains_interpolation?(str)
+      str.include?('#{')
+    end
+
+    def unescape_interpolation(str, opts = {})
+      res = ''
+      rest = Haml::Shared.handle_interpolation str.dump do |scan|
+        escapes = (scan[2].size - 1) / 2
+        res << scan.matched[0...-3 - escapes]
+        if escapes % 2 == 1
+          res << '#{'
+        else
+          content = eval('"' + balance(scan, ?{, ?}, 1)[0][0...-1] + '"')
+          content = "Haml::Helpers.html_escape(#{content})" if opts[:escape_html]
+          res << '#{' + content + "}"# Use eval to get rid of string escapes
+        end
       end
-      [spaces, spaces/2]
+      res + rest
     end
 
-    # Pushes value onto <tt>@to_close_stack</tt> and increases
-    # <tt>@template_tabs</tt>.
+    def balance(*args)
+      res = Haml::Shared.balance(*args)
+      return res if res
+      raise SyntaxError.new("Unbalanced brackets.")
+    end
+
+    def block_opened?
+      !flat? && @next_line.tabs > @line.tabs
+    end
+
+    # Pushes value onto `@to_close_stack` and increases
+    # `@template_tabs`.
     def push_and_tabulate(value)
       @to_close_stack.push(value)
       @template_tabs += 1
     end
 
     def flat?
-      @flat_spaces != -1
+      @flat
     end
 
     def newline
       @newlines += 1
     end
@@ -791,21 +1027,36 @@
       @newlines -= 1
     end
 
     def resolve_newlines
       return unless @newlines > 0
+      flush_merged_text unless @to_merge.all? {|type, *_| type == :text}
       @precompiled << "\n" * @newlines
       @newlines = 0
     end
 
     # Get rid of and whitespace at the end of the buffer
     # or the merged text
-    def rstrip_buffer!
-      unless @merged_text.empty?
-        @merged_text.rstrip!
-      else
-        push_silent("_erbout.rstrip!", false)
+    def rstrip_buffer!(index = -1)
+      last = @to_merge[index]
+      if last.nil?
+        push_silent("_hamlout.rstrip!", false)
         @dont_tab_up_next_text = true
+        return
+      end
+
+      case last.first
+      when :text
+        last[1].rstrip!
+        if last[1].empty?
+          @to_merge.slice! index
+          rstrip_buffer! index
+        end
+      when :script
+        last[1].gsub!(/\(haml_temp, (.*?)\);$/, '(haml_temp.rstrip, \1);')
+        rstrip_buffer! index - 1
+      else
+        raise SyntaxError.new("[HAML BUG] Undefined entry in Haml::Precompiler@to_merge.")
       end
     end
   end
 end