module REXML::Functions - rexml: Ruby Standard Library Documentation

# module REXML::Functions

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()”

### Constants

INTERNAL_METHODS
namespace_context
variables

### Public Class Methods

boolean(object=@@context[:node]) click to toggle source

    # File rexml-3.4.0/lib/rexml/functions.rb, line 317
    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 ) click to toggle source

    # File rexml-3.4.0/lib/rexml/functions.rb, line 417
    def Functions::ceiling( number )
      number(number).ceil
    end

compare_language(lang1, lang2) click to toggle source

    # File rexml-3.4.0/lib/rexml/functions.rb, line 370
    def Functions::compare_language lang1, lang2
      lang2.downcase.index(lang1.downcase) == 0
    end

concat( *objects ) click to toggle source

    # File rexml-3.4.0/lib/rexml/functions.rb, line 190
    def Functions::concat( *objects )
      concatenated = ""
      objects.each do |object|
        concatenated << string(object)
      end
      concatenated
    end

contains( string, test ) click to toggle source

Fixed by Mike Stok

    # File rexml-3.4.0/lib/rexml/functions.rb, line 204
    def Functions::contains( string, test )
      string(string).include?(string(test))
    end

context=(value) click to toggle source

    # File rexml-3.4.0/lib/rexml/functions.rb, line 38
    def Functions::context=(value); @@context = value; end

count( node_set ) click to toggle source

Returns the size of the given list of nodes.

    # File rexml-3.4.0/lib/rexml/functions.rb, line 60
    def Functions::count( node_set )
      node_set.size
    end

false( ) click to toggle source

UNTESTED

    # File rexml-3.4.0/lib/rexml/functions.rb, line 347
    def Functions::false(  )
      false
    end

floor( number ) click to toggle source

    # File rexml-3.4.0/lib/rexml/functions.rb, line 413
    def Functions::floor( number )
      number(number).floor
    end

get_namespace( node_set = nil ) { |context| ... } click to toggle source

Helper method.

    # File rexml-3.4.0/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 ) click to toggle source

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

    # File rexml-3.4.0/lib/rexml/functions.rb, line 66
    def Functions::id( object )
    end

lang( language ) click to toggle source

UNTESTED

    # File rexml-3.4.0/lib/rexml/functions.rb, line 352
    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( ) click to toggle source

Returns the last node of the given list of nodes.

    # File rexml-3.4.0/lib/rexml/functions.rb, line 51
    def Functions::last( )
      @@context[:size]
    end

local_name(node_set=nil) click to toggle source

    # File rexml-3.4.0/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 ) click to toggle source

    # File rexml-3.4.0/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() click to toggle source

    # File rexml-3.4.0/lib/rexml/functions.rb, line 35
    def Functions::namespace_context ; @@namespace_context ; end

namespace_context=(x) click to toggle source

    # File rexml-3.4.0/lib/rexml/functions.rb, line 33
    def Functions::namespace_context=(x) ; @@namespace_context=x ; end

namespace_uri( node_set=nil ) click to toggle source

    # File rexml-3.4.0/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 ) click to toggle source

    # File rexml-3.4.0/lib/rexml/functions.rb, line 265
    def Functions::normalize_space( string=nil )
      string = string(@@context[:node]) if string.nil?
      if string.kind_of? Array
        string.collect{|x| x.to_s.strip.gsub(/\s+/um, ' ') if x}
      else
        string.to_s.strip.gsub(/\s+/um, ' ')
      end
    end

not( object ) click to toggle source

UNTESTED

    # File rexml-3.4.0/lib/rexml/functions.rb, line 337
    def Functions::not( object )
      not boolean( object )
    end

number(object=@@context[:node]) click to toggle source

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 rexml-3.4.0/lib/rexml/functions.rb, line 387
    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

position( ) click to toggle source

    # File rexml-3.4.0/lib/rexml/functions.rb, line 55
    def Functions::position( )
      @@context[:index]
    end

processing_instruction( node ) click to toggle source

    # File rexml-3.4.0/lib/rexml/functions.rb, line 432
    def Functions::processing_instruction( node )
      node.node_type == :processing_instruction
    end

round( number ) click to toggle source

    # File rexml-3.4.0/lib/rexml/functions.rb, line 421
    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) click to toggle source
Calls superclass method

    # File rexml-3.4.0/lib/rexml/functions.rb, line 436
    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) click to toggle source

    # File rexml-3.4.0/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 ) click to toggle source

Fixed by Mike Stok

    # File rexml-3.4.0/lib/rexml/functions.rb, line 199
    def Functions::starts_with( string, test )
      string(string).index(string(test)) == 0
    end

string( object=@@context[:node] ) click to toggle source

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 rexml-3.4.0/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 ) click to toggle source

UNTESTED

    # File rexml-3.4.0/lib/rexml/functions.rb, line 261
    def Functions::string_length( string )
      string(string).length
    end

string_value( o ) click to toggle source

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 rexml-3.4.0/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 ) click to toggle source

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

    # File rexml-3.4.0/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 ) click to toggle source

Kouhei fixed this too

    # File rexml-3.4.0/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 ) click to toggle source

Kouhei fixed this

    # File rexml-3.4.0/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 ) click to toggle source

    # File rexml-3.4.0/lib/rexml/functions.rb, line 408
    def Functions::sum( nodes )
      nodes = [nodes] unless nodes.kind_of? Array
      nodes.inject(0) { |r,n| r + number(string(n)) }
    end

text( ) click to toggle source

    # File rexml-3.4.0/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 ) click to toggle source

This is entirely Mike Stok’s beast

    # File rexml-3.4.0/lib/rexml/functions.rb, line 275
    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( ) click to toggle source

UNTESTED

    # File rexml-3.4.0/lib/rexml/functions.rb, line 342
    def Functions::true( )
      true
    end

variables() click to toggle source

    # File rexml-3.4.0/lib/rexml/functions.rb, line 36
    def Functions::variables ; @@variables ; end

variables=(x) click to toggle source

    # File rexml-3.4.0/lib/rexml/functions.rb, line 34
    def Functions::variables=(x) ; @@variables=x ; end