Class: REXML::XPathParser

Inherits:
Object show all
Includes:
XMLTokens
Defined in:
lib/rexml/xpath_parser.rb

Overview

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!

Constant Summary collapse

LITERAL = 
/^'([^']*)'|^"([^"]*)"/u
ALL =

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

[ :attribute, :element, :text, :processing_instruction, :comment ]
ELEMENTS = 
[ :element ]

Constants included from XMLTokens

REXML::XMLTokens::NAME, REXML::XMLTokens::NAMECHAR, REXML::XMLTokens::NAME_STR, REXML::XMLTokens::NCNAME_STR, REXML::XMLTokens::NMTOKEN, REXML::XMLTokens::NMTOKENS, REXML::XMLTokens::REFERENCE

Instance Method Summary collapse

Constructor Details

#initialize ⇒ XPathParser

Returns a new instance of XPathParser.



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# File 'lib/rexml/xpath_parser.rb', line 39

def initialize( )
  @parser = REXML::Parsers::XPathParser.new
  @namespaces = nil
  @variables = {}
end

Instance Method Details

#[]=(variable_name, value) ⇒ Object 



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# File 'lib/rexml/xpath_parser.rb', line 76

def []=( variable_name, value )
  @variables[ variable_name ] = value
end

#first(path_stack, node) ⇒ Object

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!



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# File 'lib/rexml/xpath_parser.rb', line 85

def first( path_stack, node )
  #puts "#{depth}) Entering match( #{path.inspect}, #{tree.inspect} )"
  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
      #puts "#{depth}) CHILD checking #{name(c)}"
      r = first( path[1..-1], c )
      #puts "#{depth}) RETURNING #{r.inspect}" if r
      return r if r
    end
  when :qname
    name = path[2]
    #puts "#{depth}) QNAME #{name(tree)} == #{name} (path => #{path.size})"
    if node.name == name
      #puts "#{depth}) RETURNING #{tree.inspect}" if path.size == 3
      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) ⇒ Object 



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# File 'lib/rexml/xpath_parser.rb', line 63

def get_first path, nodeset
 #puts "#"*40
 path_stack = @parser.parse( path )
 #puts "PARSE: #{path} => #{path_stack.inspect}"
 #puts "PARSE: nodeset = #{nodeset.inspect}"
 first( path_stack, nodeset )
end

#match(path_stack, nodeset) ⇒ Object 



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# File 'lib/rexml/xpath_parser.rb', line 126

def match( path_stack, nodeset ) 
  #puts "MATCH: path_stack = #{path_stack.inspect}"
  #puts "MATCH: nodeset = #{nodeset.inspect}"
  r = expr( path_stack, nodeset )
  #puts "MAIN EXPR => #{r.inspect}"
  r
end

#namespaces=(namespaces = {}) ⇒ Object 



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# File 'lib/rexml/xpath_parser.rb', line 45

def namespaces=( namespaces={} )
  Functions::namespace_context = namespaces
  @namespaces = namespaces
end

#parse(path, nodeset) ⇒ Object 



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# File 'lib/rexml/xpath_parser.rb', line 55

def parse path, nodeset
 #puts "#"*40
 path_stack = @parser.parse( path )
 #puts "PARSE: #{path} => #{path_stack.inspect}"
 #puts "PARSE: nodeset = #{nodeset.inspect}"
 match( path_stack, nodeset )
end

#predicate(path, nodeset) ⇒ Object 



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# File 'lib/rexml/xpath_parser.rb', line 71

def predicate path, nodeset
  path_stack = @parser.parse( path )
  expr( path_stack, nodeset )
end

#variables=(vars = {}) ⇒ Object 



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# File 'lib/rexml/xpath_parser.rb', line 50

def variables=( vars={} )
  Functions::variables = vars
  @variables = vars
end