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()”

Methods
B
C
F
G
I
L
N
P
R
S
T
V
Constants
INTERNAL_METHODS = [ :namespace_context, :namespace_context=, :variables, :variables=, :context=, :get_namespace, :send, ]
 
namespace_context = namespaces
 
variables = vars
 
Class Public methods
boolean( object=nil )

UNTESTED

# File lib/rexml/functions.rb, line 296
def Functions::boolean( object=nil )
  if object.kind_of? String
    if object =~ /\d+/u
      return object.to_f != 0
    else
      return object.size > 0
    end
  elsif object.kind_of? Array
    object = object.find{|x| x and true}
  end
  return object ? true : false
end
ceiling( number )
# File lib/rexml/functions.rb, line 392
def Functions::ceiling( number )
  number(number).ceil
end
compare_language(lang1, lang2)
# File lib/rexml/functions.rb, line 343
def Functions::compare_language lang1, lang2
  lang2.downcase.index(lang1.downcase) == 0
end
concat( *objects )

UNTESTED

# File lib/rexml/functions.rb, line 171
def Functions::concat( *objects )
  objects.join
end
contains( string, test )

Fixed by Mike Stok

# File lib/rexml/functions.rb, line 181
def Functions::contains( string, test )
  string(string).include?(string(test))
end
context=(value)
# File lib/rexml/functions.rb, line 38
def Functions::context=(value); @@context = value; end
count( node_set )

Returns the size of the given list of nodes.

# File lib/rexml/functions.rb, line 60
def Functions::count( node_set )
  node_set.size
end
false( )

UNTESTED

# File lib/rexml/functions.rb, line 320
def Functions::false(  )
  false
end
floor( number )
# File lib/rexml/functions.rb, line 388
def Functions::floor( number )
  number(number).floor
end
get_namespace( node_set = nil )

Helper method.

# File lib/rexml/functions.rb, line 87
def Functions::get_namespace( node_set = nil )
  if node_set == nil
    yield @@context[:node] if defined? @@context[:node].namespace
  else
    if node_set.respond_to? :each
      node_set.each { |node| yield node if defined? node.namespace }
    elsif node_set.respond_to? :namespace
      yield node_set
    end
  end
end
id( object )

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

# File lib/rexml/functions.rb, line 66
def Functions::id( object )
end
lang( language )

UNTESTED

# File lib/rexml/functions.rb, line 325
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
last( )

Returns the last node of the given list of nodes.

# File lib/rexml/functions.rb, line 51
def Functions::last( )
  @@context[:size]
end
local_name( node_set=nil )

UNTESTED

# File lib/rexml/functions.rb, line 70
def Functions::local_name( node_set=nil )
  get_namespace( node_set ) do |node|
    return node.local_name
  end
end
name( node_set=nil )
# 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_context()
# File lib/rexml/functions.rb, line 35
def Functions::namespace_context ; @@namespace_context ; end
namespace_context=(x)
# File lib/rexml/functions.rb, line 33
def Functions::namespace_context=(x) ; @@namespace_context=x ; end
namespace_uri( node_set=nil )
# 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 )

UNTESTED

# File lib/rexml/functions.rb, line 243
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 )

UNTESTED

# File lib/rexml/functions.rb, line 310
def Functions::not( object )
  not boolean( object )
end
number( object=nil )

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

# File lib/rexml/functions.rb, line 360
def Functions::number( object=nil )
  object = @@context[:node] unless object
  case object
  when true
    Float(1)
  when false
    Float(0)
  when Array
    number(string( object ))
  when Numeric
    object.to_f
  else
    str = string( object )
    # If XPath ever gets scientific notation...
    #if str =~ /^\s*-?(\d*\.?\d+|\d+\.)([Ee]\d*)?\s*$/
    if str =~ /^\s*-?(\d*\.?\d+|\d+\.)\s*$/
      str.to_f
    else
      (0.0 / 0.0)
    end
  end
end
position( )
# File lib/rexml/functions.rb, line 55
def Functions::position( )
  @@context[:index]
end
processing_instruction( node )
# File lib/rexml/functions.rb, line 407
def Functions::processing_instruction( node )
  node.node_type == :processing_instruction
end
round( number )
# File lib/rexml/functions.rb, line 396
def Functions::round( number )
  number = number(number)
  begin
    neg = number.negative?
    number = number.abs.round(half: :up)
    neg ? -number : number
  rescue FloatDomainError
    number
  end
end
send(name, *args)
# File lib/rexml/functions.rb, line 411
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)
# 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 )

Fixed by Mike Stok

# File lib/rexml/functions.rb, line 176
def Functions::starts_with( string, test )
  string(string).index(string(test)) == 0
end
string( object=nil )

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.

# File lib/rexml/functions.rb, line 134
def Functions::string( object=nil )
  #object = @context unless object
  if object.instance_of? Array
    string( object[0] )
  elsif defined? object.node_type
    if object.node_type == :attribute
      object.value
    elsif object.node_type == :element || object.node_type == :document
      string_value(object)
    else
      object.to_s
    end
  elsif object.nil?
    return ""
  else
    object.to_s
  end
end
string_length( string )

UNTESTED

# File lib/rexml/functions.rb, line 238
def Functions::string_length( string )
  string(string).length
end
string_value( o )

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.

# File lib/rexml/functions.rb, line 158
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 )

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

# File lib/rexml/functions.rb, line 205
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 )

Kouhei fixed this too

# File lib/rexml/functions.rb, line 197
def Functions::substring_after( string, test )
  ruby_string = string(string)
  return $1 if ruby_string =~ /#{test}(.*)/
  ""
end
substring_before( string, test )

Kouhei fixed this

# File lib/rexml/functions.rb, line 186
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 )
# File lib/rexml/functions.rb, line 383
def Functions::sum( nodes )
  nodes = [nodes] unless nodes.kind_of? Array
  nodes.inject(0) { |r,n| r + number(string(n)) }
end
text( )
# 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 )

This is entirely Mike Stok's beast

# File lib/rexml/functions.rb, line 253
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
true( )

UNTESTED

# File lib/rexml/functions.rb, line 315
def Functions::true( )
  true
end
variables()
# File lib/rexml/functions.rb, line 36
def Functions::variables ; @@variables ; end
variables=(x)
# File lib/rexml/functions.rb, line 34
def Functions::variables=(x) ; @@variables=x ; end