Class: REXML::XPathParser

Inherits:
Object
  • Object
show all
Includes:
XMLTokens
Defined in:
lib/xmpp4r/rexmladdons.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

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 ]

Instance Method Summary collapse

Constructor Details

#initialize ⇒ XPathParser

LITERAL = /^‘([^’]*)‘|^“([^”]*)“/u



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# File 'lib/xmpp4r/rexmladdons.rb', line 128

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

Instance Method Details

#[]=(variable_name, value) ⇒ Object 



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# File 'lib/xmpp4r/rexmladdons.rb', line 166

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.



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# File 'lib/xmpp4r/rexmladdons.rb', line 173

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/xmpp4r/rexmladdons.rb', line 153

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/xmpp4r/rexmladdons.rb', line 214

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
  
  #while ( path_stack.size > 0 and nodeset.size > 0 ) 
  #  #puts "MATCH: #{path_stack.inspect} '#{nodeset.collect{|n|n.class}.inspect}'"
  #  nodeset = expr( path_stack, nodeset )
  #  #puts "NODESET: #{nodeset.inspect}"
  #  #puts "PATH_STACK: #{path_stack.inspect}"
  #end
  #nodeset
end

#namespaces=(namespaces) ⇒ Object 



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# File 'lib/xmpp4r/rexmladdons.rb', line 134

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

#parse(path, nodeset) ⇒ Object 



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# File 'lib/xmpp4r/rexmladdons.rb', line 145

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/xmpp4r/rexmladdons.rb', line 161

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

#variables=(vars = {}) ⇒ Object 



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# File 'lib/xmpp4r/rexmladdons.rb', line 140

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