# File lib/haml/precompiler.rb, line 134
      def tabs
        line = self
        @tabs ||= precompiler.instance_eval do
          break 0 if line.text.empty? || !(whitespace = line.full[/^\s+/])

          if @indentation.nil?
            @indentation = whitespace

            if @indentation.include?(?\s) && @indentation.include?(?\t)
              raise SyntaxError.new("Indentation can't use both tabs and spaces.", line.index)
            end

            @flat_spaces = @indentation * @template_tabs if flat?
            break 1
          end

          tabs = whitespace.length / @indentation.length
          break tabs if whitespace == @indentation * tabs
          break @template_tabs if flat? && whitespace =~ /^#{@indentation * @template_tabs}/

          raise SyntaxError.new("Inconsistent indentation: \#{Haml::Shared.human_indentation whitespace, true} used for indentation,\nbut the rest of the document was indented using \#{Haml::Shared.human_indentation @indentation}.\n".strip.gsub("\n", ' '), line.index)
        end
      end