class REXML::XPathParser - rexml: Ruby Standard Library Documentation

# class REXML::XPathParser

You don’t want to use this class. Really. Use `XPath`, which is a wrapper for this class. Believe me. You don’t want to poke around in here. There is strange, dark magic at work in this code. Beware. Go back! Go back while you still can!

### Constants

DEBUG
LITERAL

### Public Class Methods

new(strict: false) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 60
    def initialize(strict: false)
      @debug = DEBUG
      @parser = REXML::Parsers::XPathParser.new
      @namespaces = nil
      @variables = {}
      @nest = 0
      @strict = strict
    end

### Public Instance Methods

[]=( variable_name, value ) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 94
    def []=( variable_name, value )
      @variables[ variable_name ] = value
    end

first( path_stack, node ) click to toggle source

Performs a depth-first (document order) `XPath` search, and returns the first match. This is the fastest, lightest way to return a single result.

FIXME: This method is incomplete!

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 103
    def first( path_stack, node )
      return nil if path.size == 0

      case path[0]
      when :document
        # do nothing
        return first( path[1..-1], node )
      when :child
        for c in node.children
          r = first( path[1..-1], c )
          return r if r
        end
      when :qname
        name = path[2]
        if node.name == name
          return node if path.size == 3
          return first( path[3..-1], node )
        else
          return nil
        end
      when :descendant_or_self
        r = first( path[1..-1], node )
        return r if r
        for c in node.children
          r = first( path, c )
          return r if r
        end
      when :node
        return first( path[1..-1], node )
      when :any
        return first( path[1..-1], node )
      end
      return nil
    end

get_first(path, nodeset) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 84
    def get_first path, nodeset
      path_stack = @parser.parse( path )
      first( path_stack, nodeset )
    end

match(path_stack, nodeset) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 139
    def match(path_stack, nodeset)
      nodeset = nodeset.collect.with_index do |node, i|
        position = i + 1
        XPathNode.new(node, position: position)
      end
      result = expr(path_stack, nodeset)
      case result
      when Array # nodeset
        unnode(result)
      else
        [result]
      end
    end

namespaces=( namespaces={} ) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 69
    def namespaces=( namespaces={} )
      Functions::namespace_context = namespaces
      @namespaces = namespaces
    end

parse(path, nodeset) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 79
    def parse path, nodeset
      path_stack = @parser.parse( path )
      match( path_stack, nodeset )
    end

predicate(path, nodeset) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 89
    def predicate path, nodeset
      path_stack = @parser.parse( path )
      match( path_stack, nodeset )
    end

variables=( vars={} ) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 74
    def variables=( vars={} )
      Functions::variables = vars
      @variables = vars
    end

### Private Instance Methods

child(nodeset) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 779
    def child(nodeset)
      nodesets = []
      nodeset.each do |node|
        raw_node = node.raw_node
        node_type = raw_node.node_type
        # trace(:child, node_type, node)
        case node_type
        when :element
          nodesets << raw_node.children.collect.with_index do |child_node, i|
            XPathNode.new(child_node, position: i + 1)
          end
        when :document
          new_nodeset = []
          raw_node.children.each do |child|
            case child
            when XMLDecl, Text
              # Ignore
            else
              new_nodeset << XPathNode.new(child, position: new_nodeset.size + 1)
            end
          end
          nodesets << new_nodeset unless new_nodeset.empty?
        end
      end
      nodesets
    end

compare(a, operator, b) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 920
    def compare(a, operator, b)
      a, b = normalize_compare_values(a, operator, b)
      case operator
      when :eq
        a == b
      when :neq
        a != b
      when :lt
        a < b
      when :lteq
        a <= b
      when :gt
        a > b
      when :gteq
        a >= b
      else
        message = "[BUG] Unexpected compare operator: " +
          "<#{operator.inspect}>: <#{a.inspect}>: <#{b.inspect}>"
        raise message
      end
    end

descendant(nodeset, include_self) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 682
    def descendant(nodeset, include_self)
      nodesets = []
      nodeset.each do |node|
        new_nodeset = []
        new_nodes = {}
        descendant_recursive(node.raw_node, new_nodeset, new_nodes, include_self)
        nodesets << new_nodeset unless new_nodeset.empty?
      end
      nodesets
    end

descendant_recursive(raw_node, new_nodeset, new_nodes, include_self) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 693
    def descendant_recursive(raw_node, new_nodeset, new_nodes, include_self)
      if include_self
        return if new_nodes.key?(raw_node)
        new_nodeset << XPathNode.new(raw_node, position: new_nodeset.size + 1)
        new_nodes[raw_node] = true
      end

      node_type = raw_node.node_type
      if node_type == :element or node_type == :document
        raw_node.children.each do |child|
          descendant_recursive(child, new_nodeset, new_nodes, true)
        end
      end
    end

each_unnode(nodeset) { |unnoded| ... } click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 942
    def each_unnode(nodeset)
      return to_enum(__method__, nodeset) unless block_given?
      nodeset.each do |node|
        if node.is_a?(XPathNode)
          unnoded = node.raw_node
        else
          unnoded = node
        end
        yield(unnoded)
      end
    end

enter(tag, *args) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 641
    def enter(tag, *args)
      trace(:enter, tag, *args)
      @nest += 1
    end

equality_relational_compare(set1, op, set2) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 819
    def equality_relational_compare(set1, op, set2)
      set1 = unnode(set1) if set1.is_a?(Array)
      set2 = unnode(set2) if set2.is_a?(Array)

      if set1.kind_of? Array and set2.kind_of? Array
        # If both objects to be compared are node-sets, then the
        # comparison will be true if and only if there is a node in the
        # first node-set and a node in the second node-set such that the
        # result of performing the comparison on the string-values of
        # the two nodes is true.
        set1.product(set2).any? do |node1, node2|
          node_string1 = Functions.string(node1)
          node_string2 = Functions.string(node2)
          compare(node_string1, op, node_string2)
        end
      elsif set1.kind_of? Array or set2.kind_of? Array
        # If one is nodeset and other is number, compare number to each item
        # in nodeset s.t. number op number(string(item))
        # If one is nodeset and other is string, compare string to each item
        # in nodeset s.t. string op string(item)
        # If one is nodeset and other is boolean, compare boolean to each item
        # in nodeset s.t. boolean op boolean(item)
        if set1.kind_of? Array
          a = set1
          b = set2
        else
          a = set2
          b = set1
        end

        case b
        when true, false
          each_unnode(a).any? do |unnoded|
            compare(Functions.boolean(unnoded), op, b)
          end
        when Numeric
          each_unnode(a).any? do |unnoded|
            compare(Functions.number(unnoded), op, b)
          end
        when /\A\d+(\.\d+)?\z/
          b = Functions.number(b)
          each_unnode(a).any? do |unnoded|
            compare(Functions.number(unnoded), op, b)
          end
        else
          b = Functions::string(b)
          each_unnode(a).any? do |unnoded|
            compare(Functions::string(unnoded), op, b)
          end
        end
      else
        # If neither is nodeset,
        #   If op is = or !=
        #     If either boolean, convert to boolean
        #     If either number, convert to number
        #     Else, convert to string
        #   Else
        #     Convert both to numbers and compare
        compare(set1, op, set2)
      end
    end

evaluate_predicate(expression, nodesets) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 591
    def evaluate_predicate(expression, nodesets)
      enter(:predicate, expression, nodesets) if @debug
      new_nodeset_count = 0
      new_nodesets = nodesets.collect do |nodeset|
        new_nodeset = []
        subcontext = { :size => nodeset.size }
        nodeset.each_with_index do |node, index|
          if node.is_a?(XPathNode)
            subcontext[:node] = node.raw_node
            subcontext[:index] = node.position
          else
            subcontext[:node] = node
            subcontext[:index] = index + 1
          end
          result = expr(expression.dclone, [node], subcontext)
          trace(:predicate_evaluate, expression, node, subcontext, result) if @debug
          result = result[0] if result.kind_of? Array and result.length == 1
          if result.kind_of? Numeric
            if result == node.position
              new_nodeset_count += 1
              new_nodeset << XPathNode.new(node, position: new_nodeset_count)
            end
          elsif result.instance_of? Array
            if result.size > 0 and result.inject(false) {|k,s| s or k}
              if result.size > 0
                new_nodeset_count += 1
                new_nodeset << XPathNode.new(node, position: new_nodeset_count)
              end
            end
          else
            if result
              new_nodeset_count += 1
              new_nodeset << XPathNode.new(node, position: new_nodeset_count)
            end
          end
        end
        new_nodeset
      end
      new_nodesets
    ensure
      leave(:predicate, new_nodesets) if @debug
    end

expr( path_stack, nodeset, context=nil ) click to toggle source

Expr takes a stack of path elements and a set of nodes (either a `Parent` or an Array and returns an Array of matching nodes

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 175
    def expr( path_stack, nodeset, context=nil )
      enter(:expr, path_stack, nodeset) if @debug
      return nodeset if path_stack.length == 0 || nodeset.length == 0
      while path_stack.length > 0
        trace(:while, path_stack, nodeset) if @debug
        if nodeset.length == 0
          path_stack.clear
          return []
        end
        op = path_stack.shift
        case op
        when :document
          first_raw_node = nodeset.first.raw_node
          nodeset = [XPathNode.new(first_raw_node.root_node, position: 1)]
        when :self
          nodeset = step(path_stack) do
            [nodeset]
          end
        when :child
          nodeset = step(path_stack) do
            child(nodeset)
          end
        when :literal
          trace(:literal, path_stack, nodeset) if @debug
          return path_stack.shift
        when :attribute
          nodeset = step(path_stack, any_type: :attribute) do
            nodesets = []
            nodeset.each do |node|
              raw_node = node.raw_node
              next unless raw_node.node_type == :element
              attributes = raw_node.attributes
              next if attributes.empty?
              nodesets << attributes.each_attribute.collect.with_index do |attribute, i|
                XPathNode.new(attribute, position: i + 1)
              end
            end
            nodesets
          end
        when :namespace
          pre_defined_namespaces = {
            "xml" => "http://www.w3.org/XML/1998/namespace",
          }
          nodeset = step(path_stack, any_type: :namespace) do
            nodesets = []
            nodeset.each do |node|
              raw_node = node.raw_node
              case raw_node.node_type
              when :element
                if @namespaces
                  nodesets << pre_defined_namespaces.merge(@namespaces)
                else
                  nodesets << pre_defined_namespaces.merge(raw_node.namespaces)
                end
              when :attribute
                if @namespaces
                  nodesets << pre_defined_namespaces.merge(@namespaces)
                else
                  nodesets << pre_defined_namespaces.merge(raw_node.element.namespaces)
                end
              end
            end
            nodesets
          end
        when :parent
          nodeset = step(path_stack) do
            nodesets = []
            nodeset.each do |node|
              raw_node = node.raw_node
              if raw_node.node_type == :attribute
                parent = raw_node.element
              else
                parent = raw_node.parent
              end
              nodesets << [XPathNode.new(parent, position: 1)] if parent
            end
            nodesets
          end
        when :ancestor
          nodeset = step(path_stack) do
            nodesets = []
            # new_nodes = {}
            nodeset.each do |node|
              raw_node = node.raw_node
              new_nodeset = []
              while raw_node.parent
                raw_node = raw_node.parent
                # next if new_nodes.key?(node)
                new_nodeset << XPathNode.new(raw_node,
                                             position: new_nodeset.size + 1)
                # new_nodes[node] = true
              end
              nodesets << new_nodeset unless new_nodeset.empty?
            end
            nodesets
          end
        when :ancestor_or_self
          nodeset = step(path_stack) do
            nodesets = []
            # new_nodes = {}
            nodeset.each do |node|
              raw_node = node.raw_node
              next unless raw_node.node_type == :element
              new_nodeset = [XPathNode.new(raw_node, position: 1)]
              # new_nodes[node] = true
              while raw_node.parent
                raw_node = raw_node.parent
                # next if new_nodes.key?(node)
                new_nodeset << XPathNode.new(raw_node,
                                             position: new_nodeset.size + 1)
                # new_nodes[node] = true
              end
              nodesets << new_nodeset unless new_nodeset.empty?
            end
            nodesets
          end
        when :descendant_or_self
          nodeset = step(path_stack) do
            descendant(nodeset, true)
          end
        when :descendant
          nodeset = step(path_stack) do
            descendant(nodeset, false)
          end
        when :following_sibling
          nodeset = step(path_stack) do
            nodesets = []
            nodeset.each do |node|
              raw_node = node.raw_node
              next unless raw_node.respond_to?(:parent)
              next if raw_node.parent.nil?
              all_siblings = raw_node.parent.children
              current_index = all_siblings.index(raw_node)
              following_siblings = all_siblings[(current_index + 1)..-1]
              next if following_siblings.empty?
              nodesets << following_siblings.collect.with_index do |sibling, i|
                XPathNode.new(sibling, position: i + 1)
              end
            end
            nodesets
          end
        when :preceding_sibling
          nodeset = step(path_stack, order: :reverse) do
            nodesets = []
            nodeset.each do |node|
              raw_node = node.raw_node
              next unless raw_node.respond_to?(:parent)
              next if raw_node.parent.nil?
              all_siblings = raw_node.parent.children
              current_index = all_siblings.index(raw_node)
              preceding_siblings = all_siblings[0, current_index].reverse
              next if preceding_siblings.empty?
              nodesets << preceding_siblings.collect.with_index do |sibling, i|
                XPathNode.new(sibling, position: i + 1)
              end
            end
            nodesets
          end
        when :preceding
          nodeset = step(path_stack, order: :reverse) do
            unnode(nodeset) do |node|
              preceding(node)
            end
          end
        when :following
          nodeset = step(path_stack) do
            unnode(nodeset) do |node|
              following(node)
            end
          end
        when :variable
          var_name = path_stack.shift
          return [@variables[var_name]]

        when :eq, :neq, :lt, :lteq, :gt, :gteq
          left = expr( path_stack.shift, nodeset.dup, context )
          right = expr( path_stack.shift, nodeset.dup, context )
          res = equality_relational_compare( left, op, right )
          trace(op, left, right, res) if @debug
          return res

        when :or
          left = expr(path_stack.shift, nodeset.dup, context)
          return true if Functions.boolean(left)
          right = expr(path_stack.shift, nodeset.dup, context)
          return Functions.boolean(right)

        when :and
          left = expr(path_stack.shift, nodeset.dup, context)
          return false unless Functions.boolean(left)
          right = expr(path_stack.shift, nodeset.dup, context)
          return Functions.boolean(right)

        when :div, :mod, :mult, :plus, :minus
          left = expr(path_stack.shift, nodeset, context)
          right = expr(path_stack.shift, nodeset, context)
          left = unnode(left) if left.is_a?(Array)
          right = unnode(right) if right.is_a?(Array)
          left = Functions::number(left)
          right = Functions::number(right)
          case op
          when :div
            return left / right
          when :mod
            return left % right
          when :mult
            return left * right
          when :plus
            return left + right
          when :minus
            return left - right
          else
            raise "[BUG] Unexpected operator: <#{op.inspect}>"
          end
        when :union
          left = expr( path_stack.shift, nodeset, context )
          right = expr( path_stack.shift, nodeset, context )
          left = unnode(left) if left.is_a?(Array)
          right = unnode(right) if right.is_a?(Array)
          return (left | right)
        when :neg
          res = expr( path_stack, nodeset, context )
          res = unnode(res) if res.is_a?(Array)
          return -Functions.number(res)
        when :not
        when :function
          func_name = path_stack.shift.tr('-','_')
          arguments = path_stack.shift

          if nodeset.size != 1
            message = "[BUG] Node set size must be 1 for function call: "
            message += "<#{func_name}>: <#{nodeset.inspect}>: "
            message += "<#{arguments.inspect}>"
            raise message
          end

          node = nodeset.first
          if context
            target_context = context
          else
            target_context = {:size => nodeset.size}
            if node.is_a?(XPathNode)
              target_context[:node]  = node.raw_node
              target_context[:index] = node.position
            else
              target_context[:node]  = node
              target_context[:index] = 1
            end
          end
          args = arguments.dclone.collect do |arg|
            result = expr(arg, nodeset, target_context)
            result = unnode(result) if result.is_a?(Array)
            result
          end
          Functions.context = target_context
          return Functions.send(func_name, *args)

        else
          raise "[BUG] Unexpected path: <#{op.inspect}>: <#{path_stack.inspect}>"
        end
      end # while
      return nodeset
    ensure
      leave(:expr, path_stack, nodeset) if @debug
    end

filter_nodeset(nodeset) { |node| ... } click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 582
    def filter_nodeset(nodeset)
      new_nodeset = []
      nodeset.each do |node|
        next unless yield(node)
        new_nodeset << XPathNode.new(node, position: new_nodeset.size + 1)
      end
      new_nodeset
    end

following(node) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 749
    def following(node)
      followings = []
      following_node = next_sibling_node(node)
      while following_node
        followings << XPathNode.new(following_node,
                                    position: followings.size + 1)
        following_node = following_node_of(following_node)
      end
      followings
    end

following_node_of( node ) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 760
    def following_node_of( node )
      if node.kind_of? Element and node.children.size > 0
        return node.children[0]
      end
      return next_sibling_node(node)
    end

get_namespace( node, prefix ) click to toggle source

Returns a String namespace for a node, given a prefix The rules are:

    1. Use the supplied namespace mapping first.
    2. If no mapping was supplied, use the context node to look up the namespace

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 163
    def get_namespace( node, prefix )
      if @namespaces
        return @namespaces[prefix] || ''
      else
        return node.namespace( prefix ) if node.node_type == :element
        return ''
      end
    end

leave(tag, *args) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 646
    def leave(tag, *args)
      @nest -= 1
      trace(:leave, tag, *args)
    end

next_sibling_node(node) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 767
    def next_sibling_node(node)
      psn = node.next_sibling_node
      while psn.nil?
        if node.parent.nil? or node.parent.class == Document
          return nil
        end
        node = node.parent
        psn = node.next_sibling_node
      end
      return psn
    end

node_test(path_stack, nodesets, any_type: :element) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 477
    def node_test(path_stack, nodesets, any_type: :element)
      enter(:node_test, path_stack, nodesets) if @debug
      operator = path_stack.shift
      case operator
      when :qname
        prefix = path_stack.shift
        name = path_stack.shift
        new_nodesets = nodesets.collect do |nodeset|
          filter_nodeset(nodeset) do |node|
            raw_node = node.raw_node
            case raw_node.node_type
            when :element
              if prefix.nil?
                raw_node.name == name
              elsif prefix.empty?
                if strict?
                  raw_node.name == name and raw_node.namespace == ""
                else
                  # FIXME: This DOUBLES the time XPath searches take
                  ns = get_namespace(raw_node, prefix)
                  raw_node.name == name and raw_node.namespace == ns
                end
              else
                # FIXME: This DOUBLES the time XPath searches take
                ns = get_namespace(raw_node, prefix)
                raw_node.name == name and raw_node.namespace == ns
              end
            when :attribute
              if prefix.nil?
                raw_node.name == name
              elsif prefix.empty?
                raw_node.name == name and raw_node.namespace == ""
              else
                # FIXME: This DOUBLES the time XPath searches take
                ns = get_namespace(raw_node.element, prefix)
                raw_node.name == name and raw_node.namespace == ns
              end
            else
              false
            end
          end
        end
      when :namespace
        prefix = path_stack.shift
        new_nodesets = nodesets.collect do |nodeset|
          filter_nodeset(nodeset) do |node|
            raw_node = node.raw_node
            case raw_node.node_type
            when :element
              namespaces = @namespaces || raw_node.namespaces
              raw_node.namespace == namespaces[prefix]
            when :attribute
              namespaces = @namespaces || raw_node.element.namespaces
              raw_node.namespace == namespaces[prefix]
            else
              false
            end
          end
        end
      when :any
        new_nodesets = nodesets.collect do |nodeset|
          filter_nodeset(nodeset) do |node|
            raw_node = node.raw_node
            raw_node.node_type == any_type
          end
        end
      when :comment
        new_nodesets = nodesets.collect do |nodeset|
          filter_nodeset(nodeset) do |node|
            raw_node = node.raw_node
            raw_node.node_type == :comment
          end
        end
      when :text
        new_nodesets = nodesets.collect do |nodeset|
          filter_nodeset(nodeset) do |node|
            raw_node = node.raw_node
            raw_node.node_type == :text
          end
        end
      when :processing_instruction
        target = path_stack.shift
        new_nodesets = nodesets.collect do |nodeset|
          filter_nodeset(nodeset) do |node|
            raw_node = node.raw_node
            (raw_node.node_type == :processing_instruction) and
              (target.empty? or (raw_node.target == target))
          end
        end
      when :node
        new_nodesets = nodesets.collect do |nodeset|
          filter_nodeset(nodeset) do |node|
            true
          end
        end
      else
        message = "[BUG] Unexpected node test: " +
          "<#{operator.inspect}>: <#{path_stack.inspect}>"
        raise message
      end
      new_nodesets
    ensure
      leave(:node_test, path_stack, new_nodesets) if @debug
    end

norm(b) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 806
    def norm b
      case b
      when true, false
        return b
      when 'true', 'false'
        return Functions::boolean( b )
      when /^\d+(\.\d+)?$/, Numeric
        return Functions::number( b )
      else
        return Functions::string( b )
      end
    end

normalize_compare_values(a, operator, b) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 894
    def normalize_compare_values(a, operator, b)
      a_type = value_type(a)
      b_type = value_type(b)
      case operator
      when :eq, :neq
        if a_type == :boolean or b_type == :boolean
          a = Functions.boolean(a) unless a_type == :boolean
          b = Functions.boolean(b) unless b_type == :boolean
        elsif a_type == :number or b_type == :number
          a = Functions.number(a) unless a_type == :number
          b = Functions.number(b) unless b_type == :number
        else
          a = Functions.string(a) unless a_type == :string
          b = Functions.string(b) unless b_type == :string
        end
      when :lt, :lteq, :gt, :gteq
        a = Functions.number(a) unless a_type == :number
        b = Functions.number(b) unless b_type == :number
      else
        message = "[BUG] Unexpected compare operator: " +
          "<#{operator.inspect}>: <#{a.inspect}>: <#{b.inspect}>"
        raise message
      end
      [a, b]
    end

preceding(node) click to toggle source

Builds a nodeset of all of the preceding nodes of the supplied node, in reverse document order

preceding

  includes every element in the document that precedes this node,

except for ancestors

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 712
    def preceding(node)
      ancestors = []
      parent = node.parent
      while parent
        ancestors << parent
        parent = parent.parent
      end

      precedings = []
      preceding_node = preceding_node_of(node)
      while preceding_node
        if ancestors.include?(preceding_node)
          ancestors.delete(preceding_node)
        else
          precedings << XPathNode.new(preceding_node,
                                      position: precedings.size + 1)
        end
        preceding_node = preceding_node_of(preceding_node)
      end
      precedings
    end

preceding_node_of( node ) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 734
    def preceding_node_of( node )
      psn = node.previous_sibling_node
      if psn.nil?
        if node.parent.nil? or node.parent.class == Document
          return nil
        end
        return node.parent
        #psn = preceding_node_of( node.parent )
      end
      while psn and psn.kind_of? Element and psn.children.size > 0
        psn = psn.children[-1]
      end
      psn
    end

sort(array_of_nodes, order) click to toggle source

Reorders an array of nodes so that they are in document order It tries to do this efficiently.

FIXME: I need to get rid of this, but the issue is that most of the `XPath` interpreter functions as a filter, which means that we lose context going in and out of function calls. If I knew what the index of the nodes was, I wouldn’t have to do this. Maybe add a document IDX for each node? Problems with mutable documents. Or, rewrite everything.

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 659
    def sort(array_of_nodes, order)
      new_arry = []
      array_of_nodes.each { |node|
        node_idx = []
        np = node.node_type == :attribute ? node.element : node
        while np.parent and np.parent.node_type == :element
          node_idx << np.parent.index( np )
          np = np.parent
        end
        new_arry << [ node_idx.reverse, node ]
      }
      ordered = new_arry.sort_by do |index, node|
        if order == :forward
          index
        else
          -index
        end
      end
      ordered.collect do |_index, node|
        node
      end
    end

step(path_stack, any_type: :element, order: :forward) { || ... } click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 441
    def step(path_stack, any_type: :element, order: :forward)
      nodesets = yield
      begin
        enter(:step, path_stack, nodesets) if @debug
        nodesets = node_test(path_stack, nodesets, any_type: any_type)
        while path_stack[0] == :predicate
          path_stack.shift # :predicate
          predicate_expression = path_stack.shift.dclone
          nodesets = evaluate_predicate(predicate_expression, nodesets)
        end
        if nodesets.size == 1
          ordered_nodeset = nodesets[0]
        else
          raw_nodes = []
          nodesets.each do |nodeset|
            nodeset.each do |node|
              if node.respond_to?(:raw_node)
                raw_nodes << node.raw_node
              else
                raw_nodes << node
              end
            end
          end
          ordered_nodeset = sort(raw_nodes, order)
        end
        new_nodeset = []
        ordered_nodeset.each do |node|
          # TODO: Remove duplicated
          new_nodeset << XPathNode.new(node, position: new_nodeset.size + 1)
        end
        new_nodeset
      ensure
        leave(:step, path_stack, new_nodeset) if @debug
      end
    end

strict?() click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 154
    def strict?
      @strict
    end

trace(*args) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 634
    def trace(*args)
      indent = "  " * @nest
      PP.pp(args, "").each_line do |line|
        puts("#{indent}#{line}")
      end
    end

unnode(nodeset) { |unnoded| ... } click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 954
    def unnode(nodeset)
      each_unnode(nodeset).collect do |unnoded|
        unnoded = yield(unnoded) if block_given?
        unnoded
      end
    end

value_type(value) click to toggle source

    # File rexml-3.4.0/lib/rexml/xpath_parser.rb, line 881
    def value_type(value)
      case value
      when true, false
        :boolean
      when Numeric
        :number
      when String
        :string
      else
        raise "[BUG] Unexpected value type: <#{value.inspect}>"
      end
    end