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

Constants included from XMLTokens

REXML::XMLTokens::NAME, REXML::XMLTokens::NAMECHAR, REXML::XMLTokens::NAME_CHAR, REXML::XMLTokens::NAME_START_CHAR, 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 50

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 81

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 90

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) ⇒ Object 



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

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

#namespaces=(namespaces = {}) ⇒ Object 



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# File 'lib/rexml/xpath_parser.rb', line 56

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 66

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

#predicate(path, nodeset) ⇒ Object 



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

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 61

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