# class Sass::Tree::Visitors::ToCss

A visitor for converting a Sass tree into CSS.

### Constants

NEWLINE

  Avoid allocating lots of new strings for `#output`. This is important because `#output` is called all the time.

### Attributes

source_mapping[R]

The source mapping for the generated CSS file. This is only set if `build_source_mapping` is passed to the constructor and {Sass::Engine#render} has been run.

### Public Class Methods

new(build_source_mapping = false) click to toggle source

@param build_source_mapping [Boolean] Whether to build a

    \{Sass::Source::Map} while creating the CSS output. The mapping will
    be available from \{#source\_mapping} after the visitor has completed.

    # File lib/sass/tree/visitors/to_css.rb, line 11
    def initialize(build_source_mapping = false)
      @tabs = 0
      @line = 1
      @offset = 1
      @result = String.new("")
      @source_mapping = build_source_mapping ? Sass::Source::Map.new : nil
      @lstrip = nil
      @in_directive = false
    end

### Public Instance Methods

visit(node) click to toggle source

Runs the visitor on `node`.

@param node [Sass::Tree::Node] The root node of the tree to convert to CSS> @return [String] The CSS output.

Calls superclass method Sass::Tree::Visitors::Base.visit

    # File lib/sass/tree/visitors/to_css.rb, line 25
    def visit(node)
      super
    rescue Sass::SyntaxError => e
      e.modify_backtrace(:filename => node.filename, :line => node.line)
      raise e
    end

### Protected Instance Methods

erase!(chars) click to toggle source

Move the output cursor back `chars` characters.

    # File lib/sass/tree/visitors/to_css.rb, line 61
    def erase!(chars)
      return if chars == 0
      str = @result.slice!(-chars..-1)
      newlines = str.count("\n")
      if newlines > 0
        @line -= newlines
        @offset = @result[@result.rindex("\n") || 0..-1].size
      else
        @offset -= chars
      end
    end

for_node(node, attr_prefix = nil) { || ... } click to toggle source

Associate all output produced in a block with a given node. Used for source mapping.

    # File lib/sass/tree/visitors/to_css.rb, line 43
    def for_node(node, attr_prefix = nil)
      return yield unless @source_mapping
      start_pos = Sass::Source::Position.new(@line, @offset)
      yield

      range_attr = attr_prefix ? :"#{attr_prefix}_source_range" : :source_range
      return if node.invisible? || !node.send(range_attr)
      source_range = node.send(range_attr)
      target_end_pos = Sass::Source::Position.new(@line, @offset)
      target_range = Sass::Source::Range.new(start_pos, target_end_pos, nil)
      @source_mapping.add(source_range, target_range)
    end

lstrip() { || ... } click to toggle source

lstrip the first output in the given block.

    # File lib/sass/tree/visitors/to_css.rb, line 102
    def lstrip
      old_lstrip = @lstrip
      @lstrip = true
      yield
    ensure
      @lstrip &&= old_lstrip
    end

output(s) click to toggle source

Add `s` to the output string and update the line and offset information accordingly.

    # File lib/sass/tree/visitors/to_css.rb, line 79
    def output(s)
      if @lstrip
        s = s.gsub(/\A\s+/, "")
        @lstrip = false
      end

      newlines = s.count(NEWLINE)
      if newlines > 0
        @line += newlines
        @offset = s[s.rindex(NEWLINE)..-1].size
      else
        @offset += s.size
      end

      @result << s
    end

prepend!(prefix) click to toggle source

Prepend `prefix` to the output string.

    # File lib/sass/tree/visitors/to_css.rb, line 111
    def prepend!(prefix)
      @result.insert 0, prefix
      return unless @source_mapping

      line_delta = prefix.count("\n")
      offset_delta = prefix.gsub(/.*\n/, '').size
      @source_mapping.shift_output_offsets(offset_delta)
      @source_mapping.shift_output_lines(line_delta)
    end

rstrip!() click to toggle source

Strip all trailing whitespace from the output string.

    # File lib/sass/tree/visitors/to_css.rb, line 97
    def rstrip!
      erase! @result.length - 1 - (@result.rindex(/[^\s]/) || -1)
    end

trailing_semicolon?() click to toggle source

    # File lib/sass/tree/visitors/to_css.rb, line 56
    def trailing_semicolon?
     @result.end_with?(";") && !@result.end_with?('\;')
    end

visit_charset(node) click to toggle source

    # File lib/sass/tree/visitors/to_css.rb, line 155
    def visit_charset(node)
      for_node(node) {output("@charset \"#{node.name}\";")}
    end

visit_comment(node) click to toggle source

    # File lib/sass/tree/visitors/to_css.rb, line 159
    def visit_comment(node)
      return if node.invisible?
      spaces = ('  ' * [@tabs - node.resolved_value[/^ */].size, 0].max)
      output(spaces)

      content = node.resolved_value.split("\n").join("\n" + spaces)
      if node.type == :silent
        content.gsub!(%r{^(\s*)//(.*)$}) {"#{$1}/*#{$2} */"}
      end
      if (node.style == :compact || node.style == :compressed) && node.type != :loud
        content.gsub!(%r{\n +(\* *(?!/))?}, ' ')
      end
      for_node(node) {output(content)}
    end

visit_cssimport(node) click to toggle source

    # File lib/sass/tree/visitors/to_css.rb, line 259
    def visit_cssimport(node)
      visit_directive(node)
    end

visit_directive(node) click to toggle source

@comment

    rubocop:disable MethodLength

    # File lib/sass/tree/visitors/to_css.rb, line 176
    def visit_directive(node)
      was_in_directive = @in_directive
      tab_str = '  ' * @tabs
      if !node.has_children || node.children.empty?
        output(tab_str)
        for_node(node) {output(node.resolved_value)}
        if node.has_children
          output("#{' ' unless node.style == :compressed}{}")
        elsif node.children.empty?
          output(";")
        end
        return
      end

      @in_directive ||= !node.is_a?(Sass::Tree::MediaNode)
      output(tab_str) if node.style != :compressed
      for_node(node) {output(node.resolved_value)}
      output(node.style == :compressed ? "{" : " {")
      output(node.style == :compact ? ' ' : "\n") if node.style != :compressed

      had_children = true
      first = true
      node.children.each do |child|
        next if child.invisible?
        if node.style == :compact
          if child.is_a?(Sass::Tree::PropNode)
            with_tabs(first || !had_children ? 0 : @tabs + 1) do
              visit(child)
              output(' ')
            end
          else
            unless had_children
              erase! 1
              output "\n"
            end

            if first
              lstrip {with_tabs(@tabs + 1) {visit(child)}}
            else
              with_tabs(@tabs + 1) {visit(child)}
            end

            rstrip!
            output "\n"
          end
          had_children = child.has_children
          first = false
        elsif node.style == :compressed
          unless had_children
            output(";") unless trailing_semicolon?
          end
          with_tabs(0) {visit(child)}
          had_children = child.has_children
        else
          with_tabs(@tabs + 1) {visit(child)}
          output "\n"
        end
      end
      rstrip!
      if node.style == :compressed && trailing_semicolon?
        erase! 1
      end
      if node.style == :expanded
        output("\n#{tab_str}")
      elsif node.style != :compressed
        output(" ")
      end
      output("}")
    ensure
      @in_directive = was_in_directive
    end

visit_keyframerule(node) click to toggle source

@comment

    rubocop:enable MethodLength

    # File lib/sass/tree/visitors/to_css.rb, line 383
    def visit_keyframerule(node)
      visit_directive(node)
    end

visit_media(node) click to toggle source

@comment

    rubocop:enable MethodLength

    # File lib/sass/tree/visitors/to_css.rb, line 250
    def visit_media(node)
      with_tabs(@tabs + node.tabs) {visit_directive(node)}
      output("\n") if node.style != :compressed && node.group_end
    end

visit_prop(node) click to toggle source

    # File lib/sass/tree/visitors/to_css.rb, line 263
    def visit_prop(node)
      return if node.resolved_value.empty? && !node.custom_property?
      tab_str = '  ' * (@tabs + node.tabs)
      output(tab_str)
      for_node(node, :name) {output(node.resolved_name)}
      output(":")
      output(" ") unless node.style == :compressed || node.custom_property?
      for_node(node, :value) do
        output(if node.custom_property?
                 format_custom_property_value(node)
               else
                 node.resolved_value
               end)
      end
      output(";") unless node.style == :compressed
    end

visit_root(node) click to toggle source

    # File lib/sass/tree/visitors/to_css.rb, line 121
    def visit_root(node)
      node.children.each do |child|
        next if child.invisible?
        visit(child)
        next if node.style == :compressed
        output "\n"
        next unless child.is_a?(Sass::Tree::DirectiveNode) && child.has_children && !child.bubbles?
        output "\n"
      end
      rstrip!
      if node.style == :compressed && trailing_semicolon?
        erase! 1
      end
      return "" if @result.empty?

      output "\n"

      unless @result.ascii_only?
        if node.style == :compressed
          # A byte order mark is sufficient to tell browsers that this
          # file is UTF-8 encoded, and will override any other detection
          # methods as per http://encoding.spec.whatwg.org/#decode-and-encode.
          prepend! "\uFEFF"
        else
          prepend! "@charset \"UTF-8\";\n"
        end
      end

      @result
    rescue Sass::SyntaxError => e
      e.sass_template ||= node.template
      raise e
    end

visit_rule(node) click to toggle source

@comment

    rubocop:disable MethodLength

    # File lib/sass/tree/visitors/to_css.rb, line 282
    def visit_rule(node)
      with_tabs(@tabs + node.tabs) do
        rule_separator = node.style == :compressed ? ',' : ', '
        line_separator =
          case node.style
          when :nested, :expanded; "\n"
          when :compressed; ""
          else; " "
          end
        rule_indent = '  ' * @tabs
        per_rule_indent, total_indent = if [:nested, :expanded].include?(node.style)
                                          [rule_indent, '']
                                        else
                                          ['', rule_indent]
                                        end

        joined_rules = node.resolved_rules.members.map do |seq|
          next if seq.invisible?
          rule_part = seq.to_s(style: node.style, placeholder: false)
          if node.style == :compressed
            rule_part.gsub!(/([^,])\s*\n\s*/m, '\1 ')
            rule_part.gsub!(/\s*([+>])\s*/m, '\1')
            rule_part.gsub!(/nth([^( ]*)\(([^)]*)\)/m) do |match|
              match.tr(" \t\n", "")
            end
            rule_part.strip!
          end
          rule_part
        end.compact.join(rule_separator)

        joined_rules.lstrip!
        joined_rules.gsub!(/\s*\n\s*/, "#{line_separator}#{per_rule_indent}")

        old_spaces = '  ' * @tabs
        if node.style != :compressed
          if node.options[:debug_info] && !@in_directive
            visit(debug_info_rule(node.debug_info, node.options))
            output "\n"
          elsif node.options[:trace_selectors]
            output("#{old_spaces}/* ")
            output(node.stack_trace.gsub("\n", "\n   #{old_spaces}"))
            output(" */\n")
          elsif node.options[:line_comments]
            output("#{old_spaces}/* line #{node.line}")

            if node.filename
              relative_filename =
                if node.options[:css_filename]
                  begin
                    Sass::Util.relative_path_from(
                      node.filename, File.dirname(node.options[:css_filename])).to_s
                  rescue ArgumentError
                    nil
                  end
                end
              relative_filename ||= node.filename
              output(", #{relative_filename}")
            end

            output(" */\n")
          end
        end

        end_props, trailer, tabs = '', '', 0
        if node.style == :compact
          separator, end_props, bracket = ' ', ' ', ' { '
          trailer = "\n" if node.group_end
        elsif node.style == :compressed
          separator, bracket = ';', '{'
        else
          tabs = @tabs + 1
          separator, bracket = "\n", " {\n"
          trailer = "\n" if node.group_end
          end_props = (node.style == :expanded ? "\n" + old_spaces : ' ')
        end
        output(total_indent + per_rule_indent)
        for_node(node, :selector) {output(joined_rules)}
        output(bracket)

        with_tabs(tabs) do
          node.children.each_with_index do |child, i|
            if i > 0
              if separator.start_with?(";") && trailing_semicolon?
                erase! 1
              end
              output(separator)
            end
            visit(child)
          end
        end
        if node.style == :compressed && trailing_semicolon?
          erase! 1
        end

        output(end_props)
        output("}" + trailer)
      end
    end

visit_supports(node) click to toggle source

    # File lib/sass/tree/visitors/to_css.rb, line 255
    def visit_supports(node)
      visit_media(node)
    end

with_tabs(tabs) { || ... } click to toggle source

    # File lib/sass/tree/visitors/to_css.rb, line 34
    def with_tabs(tabs)
      old_tabs, @tabs = @tabs, tabs
      yield
    ensure
      @tabs = old_tabs
    end

### Private Instance Methods

debug_info_rule(debug_info, options) click to toggle source

    # File lib/sass/tree/visitors/to_css.rb, line 422
    def debug_info_rule(debug_info, options)
      node = Sass::Tree::DirectiveNode.resolved("@media -sass-debug-info")
      debug_info.map {|k, v| [k.to_s, v.to_s]}.to_a.each do |k, v|
        rule = Sass::Tree::RuleNode.new([""])
        rule.resolved_rules = Sass::Selector::CommaSequence.new(
          [Sass::Selector::Sequence.new(
            [Sass::Selector::SimpleSequence.new(
              [Sass::Selector::Element.new(k.to_s.gsub(/[^\w-]/, "\\\\\\0"), nil)],
              false)
            ])
          ])
        prop = Sass::Tree::PropNode.new([""], [""], :new)
        prop.resolved_name = "font-family"
        prop.resolved_value = Sass::SCSS::RX.escape_ident(v.to_s)
        rule << prop
        node << rule
      end
      node.options = options.merge(:debug_info => false,
                                   :line_comments => false,
                                   :style => :compressed)
      node
    end

format_custom_property_value(node) click to toggle source

Reformats the value of `node` so that it's nicely indented, preserving its existing relative indentation.

@param node [Sass::Script::Tree::PropNode] A custom property node. @return [String]

    # File lib/sass/tree/visitors/to_css.rb, line 394
    def format_custom_property_value(node)
      value = node.resolved_value.sub(/\n[ \t\r\f\n]*\Z/, ' ')
      if node.style == :compact || node.style == :compressed || !value.include?("\n")
        # Folding not involving newlines was done in the parser. We can safely
        # fold newlines here because tokens like strings can't contain literal
        # newlines, so we know any adjacent whitespace is tokenized as whitespace.
        return node.resolved_value.gsub(/[ \t\r\f]*\n[ \t\r\f\n]*/, ' ')
      end

      # Find the smallest amount of indentation in the custom property and use
      # that as the base indentation level.
      lines = value.split("\n")
      indented_lines = lines[1..-1]
      min_indentation = indented_lines.
        map {|line| line[/^[ \t]*/]}.
        reject {|line| line.empty?}.
        min_by {|line| line.length}

      # Limit the base indentation to the same indentation level as the node name
      # so that if *every* line is indented relative to the property name that's
      # preserved.
      if node.name_source_range
        base_indentation = min_indentation[0...node.name_source_range.start_pos.offset - 1]
      end

      lines.first + "\n" + indented_lines.join("\n").gsub(/^#{base_indentation}/, '  ' * @tabs)
    end