Module: REXML::Functions

Included in:
QuickPath, XPath
Defined in:
lib/rexml/functions.rb

Overview

If you add a method, keep in mind two things: (1) the first argument will always be a list of nodes from which to filter. In the case of context methods (such as position), the function should return an array with a value for each child in the array. (2) all method calls from XML will have “-” replaced with “_”. Therefore, in XML, “local-name()” is identical (and actually becomes) “local_name()”

Constant Summary collapse

INTERNAL_METHODS =
[
  :namespace_context,
  :namespace_context=,
  :variables,
  :variables=,
  :context=,
  :get_namespace,
  :send,
]
@@available_functions =
{}
@@context =
nil
@@namespace_context =
{}
@@variables =
{}

Class Method Summary collapse

Class Method Details

.boolean(object = @@context[:node]) ⇒ Object


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# File 'lib/rexml/functions.rb', line 318

def Functions::boolean(object=@@context[:node])
  case object
  when true, false
    object
  when Float
    return false if object.zero?
    return false if object.nan?
    true
  when Numeric
    not object.zero?
  when String
    not object.empty?
  when Array
    not object.empty?
  else
    object ? true : false
  end
end

.ceiling(number) ⇒ Object


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# File 'lib/rexml/functions.rb', line 418

def Functions::ceiling( number )
  number(number).ceil
end

.compare_language(lang1, lang2) ⇒ Object


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# File 'lib/rexml/functions.rb', line 371

def Functions::compare_language lang1, lang2
  lang2.downcase.index(lang1.downcase) == 0
end

.concat(*objects) ⇒ Object


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# File 'lib/rexml/functions.rb', line 190

def Functions::concat( *objects )
  concatenated = ""
  objects.each do |object|
    concatenated << string(object)
  end
  concatenated
end

.contains(string, test) ⇒ Object

Fixed by Mike Stok


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# File 'lib/rexml/functions.rb', line 204

def Functions::contains( string, test )
  string(string).include?(string(test))
end

.context=(value) ⇒ Object


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# File 'lib/rexml/functions.rb', line 38

def Functions::context=(value); @@context = value; end

.count(node_set) ⇒ Object

Returns the size of the given list of nodes.


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# File 'lib/rexml/functions.rb', line 60

def Functions::count( node_set )
  node_set.size
end

.falseObject

UNTESTED


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# File 'lib/rexml/functions.rb', line 348

def Functions::false(  )
  false
end

.floor(number) ⇒ Object


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# File 'lib/rexml/functions.rb', line 414

def Functions::floor( number )
  number(number).floor
end

.get_namespace(node_set = nil) ⇒ Object

Helper method.


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# File 'lib/rexml/functions.rb', line 87

def Functions::get_namespace( node_set = nil )
  if node_set == nil
    yield @@context[:node] if @@context[:node].respond_to?(:namespace)
  else
    if node_set.respond_to? :each
      result = []
      node_set.each do |node|
        result << yield(node) if node.respond_to?(:namespace)
      end
      result
    elsif node_set.respond_to? :namespace
      yield node_set
    end
  end
end

.id(object) ⇒ Object

Since REXML is non-validating, this method is not implemented as it requires a DTD


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# File 'lib/rexml/functions.rb', line 66

def Functions::id( object )
end

.lang(language) ⇒ Object

UNTESTED


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# File 'lib/rexml/functions.rb', line 353

def Functions::lang( language )
  lang = false
  node = @@context[:node]
  attr = nil
  until node.nil?
    if node.node_type == :element
      attr = node.attributes["xml:lang"]
      unless attr.nil?
        lang = compare_language(string(language), attr)
        break
      else
      end
    end
    node = node.parent
  end
  lang
end

.lastObject

Returns the last node of the given list of nodes.


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# File 'lib/rexml/functions.rb', line 51

def Functions::last( )
  @@context[:size]
end

.local_name(node_set = nil) ⇒ Object


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# File 'lib/rexml/functions.rb', line 69

def Functions::local_name(node_set=nil)
  get_namespace(node_set) do |node|
    return node.local_name
  end
  ""
end

.name(node_set = nil) ⇒ Object


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# File 'lib/rexml/functions.rb', line 80

def Functions::name( node_set=nil )
  get_namespace( node_set ) do |node|
    node.expanded_name
  end
end

.namespace_contextObject


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# File 'lib/rexml/functions.rb', line 35

def Functions::namespace_context ; @@namespace_context ; end

.namespace_context=(x) ⇒ Object


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# File 'lib/rexml/functions.rb', line 33

def Functions::namespace_context=(x) ; @@namespace_context=x ; end

.namespace_uri(node_set = nil) ⇒ Object


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# File 'lib/rexml/functions.rb', line 76

def Functions::namespace_uri( node_set=nil )
  get_namespace( node_set ) {|node| node.namespace}
end

.normalize_space(string = nil) ⇒ Object

UNTESTED


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# File 'lib/rexml/functions.rb', line 266

def Functions::normalize_space( string=nil )
  string = string(@@context[:node]) if string.nil?
  if string.kind_of? Array
    string.collect{|x| string.to_s.strip.gsub(/\s+/um, ' ') if string}
  else
    string.to_s.strip.gsub(/\s+/um, ' ')
  end
end

.not(object) ⇒ Object

UNTESTED


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# File 'lib/rexml/functions.rb', line 338

def Functions::not( object )
  not boolean( object )
end

.number(object = @@context[:node]) ⇒ Object

a string that consists of optional whitespace followed by an optional minus sign followed by a Number followed by whitespace is converted to the IEEE 754 number that is nearest (according to the IEEE 754 round-to-nearest rule) to the mathematical value represented by the string; any other string is converted to NaN

boolean true is converted to 1; boolean false is converted to 0

a node-set is first converted to a string as if by a call to the string function and then converted in the same way as a string argument

an object of a type other than the four basic types is converted to a number in a way that is dependent on that type


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# File 'lib/rexml/functions.rb', line 388

def Functions::number(object=@@context[:node])
  case object
  when true
    Float(1)
  when false
    Float(0)
  when Array
    number(string(object))
  when Numeric
    object.to_f
  else
    str = string(object)
    case str.strip
    when /\A\s*(-?(?:\d+(?:\.\d*)?|\.\d+))\s*\z/
      $1.to_f
    else
      Float::NAN
    end
  end
end

.positionObject


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# File 'lib/rexml/functions.rb', line 55

def Functions::position( )
  @@context[:index]
end

.processing_instruction(node) ⇒ Object


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# File 'lib/rexml/functions.rb', line 433

def Functions::processing_instruction( node )
  node.node_type == :processing_instruction
end

.round(number) ⇒ Object


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# File 'lib/rexml/functions.rb', line 422

def Functions::round( number )
  number = number(number)
  begin
    neg = number.negative?
    number = number.abs.round
    neg ? -number : number
  rescue FloatDomainError
    number
  end
end

.send(name, *args) ⇒ Object


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# File 'lib/rexml/functions.rb', line 437

def Functions::send(name, *args)
  if @@available_functions[name.to_sym]
    super
  else
    # TODO: Maybe, this is not XPath spec behavior.
    # This behavior must be reconsidered.
    XPath.match(@@context[:node], name.to_s)
  end
end

.singleton_method_added(name) ⇒ Object


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# File 'lib/rexml/functions.rb', line 26

def singleton_method_added(name)
  unless INTERNAL_METHODS.include?(name)
    @@available_functions[name] = true
  end
end

.starts_with(string, test) ⇒ Object

Fixed by Mike Stok


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# File 'lib/rexml/functions.rb', line 199

def Functions::starts_with( string, test )
  string(string).index(string(test)) == 0
end

.string(object = @@context[:node]) ⇒ Object

A node-set is converted to a string by returning the string-value of the node in the node-set that is first in document order. If the node-set is empty, an empty string is returned.

A number is converted to a string as follows

NaN is converted to the string NaN

positive zero is converted to the string 0

negative zero is converted to the string 0

positive infinity is converted to the string Infinity

negative infinity is converted to the string -Infinity

if the number is an integer, the number is represented in decimal form as a Number with no decimal point and no leading zeros, preceded by a minus sign (-) if the number is negative

otherwise, the number is represented in decimal form as a Number including a decimal point with at least one digit before the decimal point and at least one digit after the decimal point, preceded by a minus sign (-) if the number is negative; there must be no leading zeros before the decimal point apart possibly from the one required digit immediately before the decimal point; beyond the one required digit after the decimal point there must be as many, but only as many, more digits as are needed to uniquely distinguish the number from all other IEEE 754 numeric values.

The boolean false value is converted to the string false. The boolean true value is converted to the string true.

An object of a type other than the four basic types is converted to a string in a way that is dependent on that type.


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# File 'lib/rexml/functions.rb', line 138

def Functions::string( object=@@context[:node] )
  if object.respond_to?(:node_type)
    case object.node_type
    when :attribute
      object.value
    when :element
      string_value(object)
    when :document
      string_value(object.root)
    when :processing_instruction
      object.content
    else
      object.to_s
    end
  else
    case object
    when Array
      string(object[0])
    when Float
      if object.nan?
        "NaN"
      else
        integer = object.to_i
        if object == integer
          "%d" % integer
        else
          object.to_s
        end
      end
    else
      object.to_s
    end
  end
end

.string_length(string) ⇒ Object

UNTESTED


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# File 'lib/rexml/functions.rb', line 261

def Functions::string_length( string )
  string(string).length
end

.string_value(o) ⇒ Object

A node-set is converted to a string by returning the concatenation of the string-value of each of the children of the node in the node-set that is first in document order. If the node-set is empty, an empty string is returned.


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# File 'lib/rexml/functions.rb', line 178

def Functions::string_value( o )
  rv = ""
  o.children.each { |e|
    if e.node_type == :text
      rv << e.to_s
    elsif e.node_type == :element
      rv << string_value( e )
    end
  }
  rv
end

.substring(string, start, length = nil) ⇒ Object

Take equal portions of Mike Stok and Sean Russell; mix vigorously, and pour into a tall, chilled glass. Serves 10,000.


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# File 'lib/rexml/functions.rb', line 228

def Functions::substring( string, start, length=nil )
  ruby_string = string(string)
  ruby_length = if length.nil?
                  ruby_string.length.to_f
                else
                  number(length)
                end
  ruby_start = number(start)

  # Handle the special cases
  return '' if (
    ruby_length.nan? or
    ruby_start.nan? or
    ruby_start.infinite?
  )

  infinite_length = ruby_length.infinite? == 1
  ruby_length = ruby_string.length if infinite_length

  # Now, get the bounds.  The XPath bounds are 1..length; the ruby bounds
  # are 0..length.  Therefore, we have to offset the bounds by one.
  ruby_start = round(ruby_start) - 1
  ruby_length = round(ruby_length)

  if ruby_start < 0
   ruby_length += ruby_start unless infinite_length
   ruby_start = 0
  end
  return '' if ruby_length <= 0
  ruby_string[ruby_start,ruby_length]
end

.substring_after(string, test) ⇒ Object

Kouhei fixed this too


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# File 'lib/rexml/functions.rb', line 220

def Functions::substring_after( string, test )
  ruby_string = string(string)
  return $1 if ruby_string =~ /#{test}(.*)/
  ""
end

.substring_before(string, test) ⇒ Object

Kouhei fixed this


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# File 'lib/rexml/functions.rb', line 209

def Functions::substring_before( string, test )
  ruby_string = string(string)
  ruby_index = ruby_string.index(string(test))
  if ruby_index.nil?
    ""
  else
    ruby_string[ 0...ruby_index ]
  end
end

.sum(nodes) ⇒ Object


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# File 'lib/rexml/functions.rb', line 409

def Functions::sum( nodes )
  nodes = [nodes] unless nodes.kind_of? Array
  nodes.inject(0) { |r,n| r + number(string(n)) }
end

.textObject


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# File 'lib/rexml/functions.rb', line 40

def Functions::text( )
  if @@context[:node].node_type == :element
    return @@context[:node].find_all{|n| n.node_type == :text}.collect{|n| n.value}
  elsif @@context[:node].node_type == :text
    return @@context[:node].value
  else
    return false
  end
end

.translate(string, tr1, tr2) ⇒ Object

This is entirely Mike Stok's beast


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# File 'lib/rexml/functions.rb', line 276

def Functions::translate( string, tr1, tr2 )
  from = string(tr1)
  to = string(tr2)

  # the map is our translation table.
  #
  # if a character occurs more than once in the
  # from string then we ignore the second &
  # subsequent mappings
  #
  # if a character maps to nil then we delete it
  # in the output.  This happens if the from
  # string is longer than the to string
  #
  # there's nothing about - or ^ being special in
  # http://www.w3.org/TR/xpath#function-translate
  # so we don't build ranges or negated classes

  map = Hash.new
  0.upto(from.length - 1) { |pos|
    from_char = from[pos]
    unless map.has_key? from_char
      map[from_char] =
      if pos < to.length
        to[pos]
      else
        nil
      end
    end
  }

  if ''.respond_to? :chars
    string(string).chars.collect { |c|
      if map.has_key? c then map[c] else c end
    }.compact.join
  else
    string(string).unpack('U*').collect { |c|
      if map.has_key? c then map[c] else c end
    }.compact.pack('U*')
  end
end

.trueObject

UNTESTED


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# File 'lib/rexml/functions.rb', line 343

def Functions::true( )
  true
end

.variablesObject


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# File 'lib/rexml/functions.rb', line 36

def Functions::variables ; @@variables ; end

.variables=(x) ⇒ Object


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# File 'lib/rexml/functions.rb', line 34

def Functions::variables=(x) ; @@variables=x ; end