Class: REXML::Parsers::XPathParser

Inherits:
Object
  • Object
show all
Includes:
XMLTokens
Defined in:
lib/rexml/parsers/xpathparser.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
AXIS =

RelativeLocationPath

|                                                    Step
  | (AXIS_NAME '::' | '@' | '')                     AxisSpecifier
    NodeTest
      Predicate
  | '.' | '..'                                      AbbreviatedStep
|  RelativeLocationPath '/' Step
| RelativeLocationPath '//' Step
/^(ancestor|ancestor-or-self|attribute|child|descendant|descendant-or-self|following|following-sibling|namespace|parent|preceding|preceding-sibling|self)::/
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
/^(#{NCNAME_STR}):\*/u
QNAME =
Namespace::NAMESPLIT
NODE_TYPE =
/^(comment|text|node)\(\s*\)/m
PI =
/^processing-instruction\(/
VARIABLE_REFERENCE =

| VARIABLE_REFERENCE | '(' expr ')' | LITERAL | NUMBER | FunctionCall

/^\$(#{NAME_STR})/u
NUMBER =
/^(\d*\.?\d+)/
NT =
/^comment|text|processing-instruction|node$/

Constants included from XMLTokens

XMLTokens::NAME, XMLTokens::NAMECHAR, XMLTokens::NAME_STR, XMLTokens::NCNAME_STR, XMLTokens::NMTOKEN, XMLTokens::NMTOKENS, XMLTokens::REFERENCE

Instance Method Summary collapse

Instance Method Details

#abbreviate(path) ⇒ Object



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# File 'lib/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) ⇒ Object



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# File 'lib/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) ⇒ Object



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# File 'lib/rexml/parsers/xpathparser.rb', line 14

def namespaces=( namespaces )
  Functions::namespace_context = namespaces
  @namespaces = namespaces
end

#parse(path) ⇒ Object



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# File 'lib/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) ⇒ Object



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# File 'lib/rexml/parsers/xpathparser.rb', line 27

def predicate path
  parsed = []
  Predicate( "[#{path}]", parsed )
  parsed
end

#predicate_to_string(path, &block) ⇒ Object



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# File 'lib/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