In Files

  • rexml/parsers/xpathparser.rb

REXML::Parsers::XPathParser

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!

Constants

AXIS

RelativeLocationPath

|                                                    Step
  | (AXIS_NAME '::' | '@' | '')                     AxisSpecifier
    NodeTest
      Predicate
  | '.' | '..'                                      AbbreviatedStep
|  RelativeLocationPath '/' Step
| RelativeLocationPath '//' Step
LITERAL
NCNAMETEST
Returns a 1-1 map of the nodeset
The contents of the resulting array are either:
  true/false, if a positive match
  String, if a name match

NodeTest

| ('*' | NCNAME ':' '*' | QNAME)                NameTest
| NODE_TYPE '(' ')'                              NodeType
| PI '(' LITERAL ')'                            PI
  | '[' expr ']'                                Predicate
NODE_TYPE
NT
NUMBER
PI
QNAME
VARIABLE_REFERENCE

| VARIABLE_REFERENCE | ‘(’ expr ‘)’ | LITERAL | NUMBER | FunctionCall

Public Instance Methods

abbreviate( path ) click to toggle source
 
               # File rexml/parsers/xpathparser.rb, line 33
def abbreviate( path )
  path = path.kind_of?(String) ? parse( path ) : path
  string = ""
  document = false
  while path.size > 0
    op = path.shift
    case op
    when :node
    when :attribute
                                          string << "/" if string.size > 0
                                          string << "@"
    when :child
                                          string << "/" if string.size > 0
    when :descendant_or_self
      string << "/"
    when :self
      string << "."
    when :parent
      string << ".."
    when :any
      string << "*"
                                  when :text
                                          string << "text()"
    when :following, :following_sibling, 
          :ancestor, :ancestor_or_self, :descendant, 
          :namespace, :preceding, :preceding_sibling
      string << "/" unless string.size == 0
      string << op.to_s.tr("_", "-")
      string << "::"
    when :qname
      prefix = path.shift
      name = path.shift
      string << prefix+":" if prefix.size > 0
      string << name
    when :predicate
      string << '['
      string << predicate_to_string( path.shift ) {|x| abbreviate( x ) }
      string << ']'
    when :document
      document = true
                                  when :function
                                          string << path.shift
                                          string << "( "
                                          string << predicate_to_string( path.shift[0] ) {|x| abbreviate( x )}
                                          string << " )"
                                  when :literal
                                          string << %Q{ "#{path.shift}" }
    else
      string << "/" unless string.size == 0
      string << "UNKNOWN("
      string << op.inspect
      string << ")"
    end
  end
                          string = "/"+string if document
  return string
end
            
expand( path ) click to toggle source
 
               # File rexml/parsers/xpathparser.rb, line 91
def expand( path )
  path = path.kind_of?(String) ? parse( path ) : path
  string = ""
  document = false
  while path.size > 0
    op = path.shift
    case op
    when :node
      string << "node()"
    when :attribute, :child, :following, :following_sibling, 
          :ancestor, :ancestor_or_self, :descendant, :descendant_or_self,
          :namespace, :preceding, :preceding_sibling, :self, :parent
      string << "/" unless string.size == 0
      string << op.to_s.tr("_", "-")
      string << "::"
    when :any
      string << "*"
    when :qname
      prefix = path.shift
      name = path.shift
      string << prefix+":" if prefix.size > 0
      string << name
    when :predicate
      string << '['
      string << predicate_to_string( path.shift ) { |x| expand(x) }
      string << ']'
    when :document
      document = true
    else
      string << "/" unless string.size == 0
      string << "UNKNOWN("
      string << op.inspect
      string << ")"
    end
  end
  string = "/"+string if document
  return string
end
            
namespaces=( namespaces ) click to toggle source
 
               # File rexml/parsers/xpathparser.rb, line 14
def namespaces=( namespaces )
  Functions::namespace_context = namespaces
  @namespaces = namespaces
end
            
parse(path) click to toggle source
 
               # File rexml/parsers/xpathparser.rb, line 19
def parse path
  path.gsub!(/([\(\[])\s+/, '\1') # Strip ignorable spaces
  path.gsub!( /\s+([\]\)])/, '\1' )
  parsed = []
  path = OrExpr(path, parsed)
  parsed
end
            
predicate(path) click to toggle source
 
               # File rexml/parsers/xpathparser.rb, line 27
def predicate path
  parsed = []
  Predicate( "[#{path}]", parsed )
  parsed
end
            
predicate_to_string( path, &block ) click to toggle source
 
               # File rexml/parsers/xpathparser.rb, line 130
def predicate_to_string( path, &block )
  string = ""
  case path[0]
  when :and, :or, :mult, :plus, :minus, :neq, :eq, :lt, :gt, :lteq, :gteq, :div, :mod, :union
    op = path.shift
    case op
    when :eq
      op = "="
    when :lt
      op = "<"
    when :gt
      op = ">"
    when :lteq
      op = "<="
    when :gteq
      op = ">="
    when :neq
      op = "!="
    when :union
      op = "|"
    end
    left = predicate_to_string( path.shift, &block )
    right = predicate_to_string( path.shift, &block )
    string << " "
    string << left
    string << " "
    string << op.to_s
    string << " "
    string << right
    string << " "
  when :function
    path.shift
    name = path.shift
    string << name
    string << "( "
    string << predicate_to_string( path.shift, &block )
    string << " )"
  when :literal
    path.shift
    string << " "
    string << path.shift.inspect
    string << " "
  else
    string << " "
    string << yield( path )
    string << " "
  end
  return string.squeeze(" ")
end
            

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