class XPathParser

token Number Literal Operator NameTest AxisName NodeType FunctionName VariableReference    


start LocationPath

rule

LocationPath : RelativeLocationPath 
             | AbsoluteLocationPath 
             ;

AbsoluteLocationPath : '/' 
		     | '/' RelativeLocationPath
		     ;


RelativeLocationPath : Step { puts "Relative Location Path" }
                     | RelativeLocationPath '/' Step
		     ;

Step : AxisSpecifier NodeTest Predicates { puts "Step" }
     ;

AxisSpecifier : AxisName '::' { puts "AxisSpecifier" }
              ;





OtherNodeTypes : 'comment'
               | 'text'
               | 'node'
               ;

##### here's the error

NodeTest : NameTest  { puts "NameTest" }
         | 'processing-instruction' '(' Literal ')'  { puts "PI" }
         | OtherNodeTypes '(' ')' { puts "other" }
         ;

Predicates : /* empty */
           | Predicates Predicate
           {
           puts "Predicates"
           }


Predicate :  '[' ']'
         {
          puts "Predicate"
         }

end

---- header

require "tokenizer"

---- inner

def parse( str )
  @tokenizer = Tokenizer.new(str)
  do_parse
end

def next_token
  tok = @tokenizer.next_token
  if tok.nil?
    [false, '$']
  else
    if tok.size == 1 then
      [tok[0], tok[0]]
    else
      tok
    end
  end
end

---- footer

if $0 == __FILE__ then
  $DEBUG=true

  src = "child::processing-instruction ( 'hallo' ) []"

  puts "parsing:"
  puts src


  XPathParser.new.parse(src)
end