Override the Slim parser to add default whitespace for some tags.

slim.rb

# Override the Slim parser to add default whitespace for some tags.

module Slim
  class Parser < Temple::Parser
    alias :old_parse_tag :parse_tag

    WHITESPACE_MODIFIER = '<'
    TAGS_TO_ADD_WHITESPACE = %w[. # div span]

    def parse_tag(tag)
      insert_whitespace = false
      TAGS_TO_ADD_WHITESPACE.each do |t|
        insert_whitespace = true if t == tag
      end

      if insert_whitespace
        if @line =~ /(^.*)\s(.*)/
          @line = "#{$1}#{WHITESPACE_MODIFIER} #{$2}"
        else
          @line << WHITESPACE_MODIFIER
        end
      end

      old_parse_tag tag
    end
  end
end