35:     def initialize( )
36:       @parser = REXML::Parsers::XPathParser.new
37:       @namespaces = {}
38:       @variables = {}
39:     end

72:     def []=( variable_name, value )
73:       @variables[ variable_name ] = value
74:     end

 81:     def first( path_stack, node )
 82:       #puts "#{depth}) Entering match( #{path.inspect}, #{tree.inspect} )"
 83:       return nil if path.size == 0
 84: 
 85:       case path[0]
 86:       when :document
 87:         # do nothing 
 88:         return first( path[1..-1], node )
 89:       when :child
 90:         for c in node.children
 91:           #puts "#{depth}) CHILD checking #{name(c)}"
 92:           r = first( path[1..-1], c )
 93:           #puts "#{depth}) RETURNING #{r.inspect}" if r
 94:           return r if r
 95:         end
 96:       when :qname
 97:         name = path[2]
 98:         #puts "#{depth}) QNAME #{name(tree)} == #{name} (path => #{path.size})"
 99:         if node.name == name
100:           #puts "#{depth}) RETURNING #{tree.inspect}" if path.size == 3
101:           return node if path.size == 3
102:           return first( path[3..-1], node )
103:         else
104:           return nil
105:         end
106:       when :descendant_or_self
107:         r = first( path[1..-1], node )
108:         return r if r
109:         for c in node.children
110:           r = first( path, c )
111:           return r if r
112:         end
113:       when :node
114:         return first( path[1..-1], node )
115:       when :any
116:         return first( path[1..-1], node )
117:       end
118:       return nil
119:     end

59:     def get_first path, nodeset
60:      #puts "#"*40
61:      path_stack = @parser.parse( path )
62:      #puts "PARSE: #{path} => #{path_stack.inspect}"
63:      #puts "PARSE: nodeset = #{nodeset.inspect}"
64:      first( path_stack, nodeset )
65:     end

122:     def match( path_stack, nodeset ) 
123:       #puts "MATCH: path_stack = #{path_stack.inspect}"
124:       #puts "MATCH: nodeset = #{nodeset.inspect}"
125:       r = expr( path_stack, nodeset )
126:       #puts "MAIN EXPR => #{r.inspect}"
127:       r
128:     end

41:     def namespaces=( namespaces={} )
42:       Functions::namespace_context = namespaces
43:       @namespaces = namespaces
44:     end

51:     def parse path, nodeset
52:      #puts "#"*40
53:      path_stack = @parser.parse( path )
54:      #puts "PARSE: #{path} => #{path_stack.inspect}"
55:      #puts "PARSE: nodeset = #{nodeset.inspect}"
56:      match( path_stack, nodeset )
57:     end

67:     def predicate path, nodeset
68:       path_stack = @parser.parse( path )
69:       expr( path_stack, nodeset )
70:     end

46:     def variables=( vars={} )
47:       Functions::variables = vars
48:       @variables = vars
49:     end