class Sass::Tree::Visitors::Extend

A visitor for performing selector inheritance on a static CSS tree.

Destructively modifies the tree.

Public Class Methods

new(extends) click to toggle source
# File lib/sass/tree/visitors/extend.rb, line 21
def initialize(extends)
  @parent_directives = []
  @extends = extends
end
visit(root, extends) click to toggle source

Performs the given extensions on the static CSS tree based in `root`, then validates that all extends matched some selector.

@param root [Tree::Node] The root node of the tree to visit. @param extends [Sass::Util::SubsetMap{Selector::Simple =>

                                    Sass::Tree::Visitors::Cssize::Extend}]
The extensions to perform on this tree.

@return [Object] The return value of {#visit} for the root node.

# File lib/sass/tree/visitors/extend.rb, line 13
def self.visit(root, extends)
  return if extends.empty?
  new(extends).send(:visit, root)
  check_extends_fired! extends
end

Private Class Methods

check_extends_fired!(extends) click to toggle source
# File lib/sass/tree/visitors/extend.rb, line 49
  def self.check_extends_fired!(extends)
    extends.each_value do |ex|
      next if ex.result == :succeeded || ex.node.optional?
      message = "\"#{ex.extender}\" failed to @extend \"#{ex.target.join}\"."
      reason =
        if ex.result == :not_found
          "The selector \"#{ex.target.join}\" was not found."
        else
          "No selectors matching \"#{ex.target.join}\" could be unified with \"#{ex.extender}\"."
        end

      # TODO(nweiz): this should use the Sass stack trace of the extend node.
      raise Sass::SyntaxError.new("#{message}
#{reason}
Use "@extend #{ex.target.join} !optional" if the extend should be able to fail.
", :filename => ex.node.filename, :line => ex.node.line)
    end
  end

Protected Instance Methods

visit(node) click to toggle source

If an exception is raised, this adds proper metadata to the backtrace.

Calls superclass method Sass::Tree::Visitors::Base.visit
# File lib/sass/tree/visitors/extend.rb, line 27
def visit(node)
  super(node)
rescue Sass::SyntaxError => e
  e.modify_backtrace(:filename => node.filename, :line => node.line)
  raise e
end
visit_children(parent) click to toggle source

Keeps track of the current parent directives.

# File lib/sass/tree/visitors/extend.rb, line 35
def visit_children(parent)
  @parent_directives.push parent if parent.is_a?(Sass::Tree::DirectiveNode)
  super
ensure
  @parent_directives.pop if parent.is_a?(Sass::Tree::DirectiveNode)
end
visit_rule(node) click to toggle source

Applies the extend to a single rule's selector.

# File lib/sass/tree/visitors/extend.rb, line 43
def visit_rule(node)
  node.resolved_rules = node.resolved_rules.do_extend(@extends, @parent_directives)
end