plexus/hexp

module Hexp
  # Represents text inside HTML. Instances behave like Strings, but also support
  # the most of `Hexp::Node` interface, so you don't have to treat them differently
  # when traversing across trees.
  #
  # Strings used inside Hexp literals like `H[:span, "Hi!"]` automatically get
  # converted to `TextNode` instances, so there is usually no reason to instantiate
  # these yourself.
  class TextNode < DelegateClass(String)
    # Inspect the TextNode
    #
    # This delegates to the underlying String, making it
    # non-obvious that you're dealing with something else. However, a TextNode
    # supports the full API of String, so this might not be a big problem.
    # The benefit is that inspection of complete nodes containing text looks
    # nice
    #
    # @example
    #   Hexp::TextNode.new("hello, world").inspect #=> "\"hello, world\""
    #
    # @return [String]
    #
    # @api public
    #
    def inspect
      __getobj__.inspect
    end

    # The attributes of this Node
    #
    # Text nodes can not have attributes, so this always returns an empty Hash.
    #
    # @return [Hash]
    #
    # @api public
    #
    def attributes
      {}.freeze
    end

    # Same as inspect, used by `Hexp::Node#pp`
    #
    # @example
    #   Hexp::TextNode.new("hello, world").pp #=> "\"hello, world\""
    #
    # @return [String]
    #
    # @api public
    #
    def pp
      inspect
    end

    # The tag of this node
    #
    # A text node does not have a tag, so this returns nil
    #
    # @example
    #   Hexp::TextNode.new("hello, world").tag #=> nil
    #
    # @return [NilClass]
    #
    # @api public
    #
    def tag
    end

    # Standard conversion protocol, returns self
    #
    # @example
    #   Hexp::TextNode.new("hello, world").to_hexp #=> #<Hexp::TextNode "hello, world">
    #
    # @return [Hexp::TextNode]
    #
    # @api public
    #
    def to_hexp
      self
    end

    # Children of the node
    #
    # A text node has no children, this always returns an empty array.
    #
    # @example
    #   Hexp::TextNode.new("hello, world").children #=> []
    #
    # @return [Array]
    #
    # @api public
    #
    def children
      [].freeze
    end

    # Is this a text node?
    #
    # @example
    #   Hexp::TextNode.new('foo').text? #=> true
    #   H[:p].text? #=> false
    #
    # @return [TrueClass]
    #
    # @api public
    #
    def text?
      true
    end

    # Is a certain CSS class present on this node?
    #
    # Text nodes have no attributes, so this always returns false.
    #
    # @example
    #   Hexp::TextNode.new('foo').class?('bar') #=> false
    #
    # @return [FalseClass]
    #
    # @api public
    #
    def class?(klz)
      false
    end

    # Rewrite a node
    #
    # See Hexp::Node#rewrite for more info. On a TextNode this simply return self.
    #
    # @example
    #   tree.rewrite do |node|
    #     H[:div, {class: 'wrap'}, node]
    #   end
    #
    # @return [Hexp::TextNode]
    #
    # @api public
    #
    def rewrite(&blk)
      self
    end

    def select(&block)
      Node::Selection.new(self, block)
    end

    def to_html(opts = {})
      Unparser.new(opts).call(self)
    end
  end
end