# class Psych::Visitors::YAMLTree

YAMLTree builds a YAML ast given a Ruby object. For example:

    builder = Psych::Visitors::YAMLTree.new
    builder << { :foo => 'bar' }
    builder.tree # => #<Psych::Nodes::Stream .. }

### Constants

BINARY_RANGE
NULL

  FIXME: Remove the index and count checks in Psych 3.0

WS_RANGE

### Attributes

finished[R]
finished?[R]
started[R]
started?[R]

### Public Class Methods

create(options = {}) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 49
    def self.create options = {}, emitter = nil
      emitter      ||= TreeBuilder.new
      class_loader = ClassLoader.new
      ss           = ScalarScanner.new class_loader
      new(emitter, ss, options)
    end

new(emitter = nil, ss = nil, options = nil) click to toggle source
Calls superclass method

    # File lib/psych/visitors/yaml_tree.rb, line 56
    def self.new emitter = nil, ss = nil, options = nil
      return super if emitter && ss && options

      if $VERBOSE
        warn "This API is deprecated, please pass an emitter, scalar scanner, and options or call #{self}.create() (#{caller.first})"
      end
      create emitter, ss
    end

new(emitter, ss, options) click to toggle source
Calls superclass method

    # File lib/psych/visitors/yaml_tree.rb, line 65
    def initialize emitter, ss, options
      super()
      @started    = false
      @finished   = false
      @emitter    = emitter
      @st         = Registrar.new
      @ss         = ss
      @options    = options
      @line_width = options[:line_width]
      if @line_width && @line_width < 0
        if @line_width == -1
          # Treat -1 as unlimited line-width, same as libyaml does.
          @line_width = nil
        else
          fail(ArgumentError, "Invalid line_width #{@line_width}, must be non-negative or -1 for unlimited.")
        end
      end
      @coders     = []

      @dispatch_cache = Hash.new do |h,klass|
        method = "visit_#{(klass.name || '').split('::').join('_')}"

        method = respond_to?(method) ? method : h[klass.superclass]

        raise(TypeError, "Can't dump #{target.class}") unless method

        h[klass] = method
      end
    end

### Public Instance Methods

<<(object)
Alias for: push
accept(target) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 132
    def accept target
      # return any aliases we find
      if @st.key? target
        oid         = @st.id_for target
        node        = @st.node_for target
        anchor      = oid.to_s
        node.anchor = anchor
        return @emitter.alias anchor
      end

      if target.respond_to?(:to_yaml)
        begin
          loc = target.method(:to_yaml).source_location.first
          if loc !~ /(syck\/rubytypes.rb|psych\/core_ext.rb)/
            unless target.respond_to?(:encode_with)
              if $VERBOSE
                warn "implementing to_yaml is deprecated, please implement \"encode_with\""
              end

              target.to_yaml(:nodump => true)
            end
          end
        rescue
          # public_method or source_location might be overridden,
          # and it's OK to skip it since it's only to emit a warning
        end
      end

      if target.respond_to?(:encode_with)
        dump_coder target
      else
        send(@dispatch_cache[target.class], target)
      end
    end

finish() click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 101
    def finish
      @emitter.end_stream.tap do
        @finished = true
      end
    end

push(object) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 112
    def push object
      start unless started?
      version = []
      version = [1,1] if @options[:header]

      case @options[:version]
      when Array
        version = @options[:version]
      when String
        version = @options[:version].split('.').map { |x| x.to_i }
      else
        version = [1,1]
      end if @options.key? :version

      @emitter.start_document version, [], false
      accept object
      @emitter.end_document !@emitter.streaming?
    end

Also aliased as: <<
start(encoding = Nodes::Stream::UTF8) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 95
    def start encoding = Nodes::Stream::UTF8
      @emitter.start_stream(encoding).tap do
        @started = true
      end
    end

tree() click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 107
    def tree
      finish unless finished?
      @emitter.root
    end

visit_Array(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 404
    def visit_Array o
      if o.class == ::Array
        register o, @emitter.start_sequence(nil, nil, true, Nodes::Sequence::BLOCK)
        o.each { |c| accept c }
        @emitter.end_sequence
      else
        visit_array_subclass o
      end
    end

visit_BasicObject(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 426
    def visit_BasicObject o
      tag = Psych.dump_tags[o.class]
      tag ||= "!ruby/marshalable:#{o.class.name}"

      map = @emitter.start_mapping(nil, tag, false, Nodes::Mapping::BLOCK)
      register(o, map)

      o.marshal_dump.each(&method(:accept))

      @emitter.end_mapping
    end

visit_BigDecimal(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 306
    def visit_BigDecimal o
      @emitter.scalar o._dump, nil, '!ruby/object:BigDecimal', false, false, Nodes::Scalar::ANY
    end

visit_Class(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 367
    def visit_Class o
      raise TypeError, "can't dump anonymous class: #{o}" unless o.name
      register o, @emitter.scalar(o.name, nil, '!ruby/class', false, false, Nodes::Scalar::SINGLE_QUOTED)
    end

visit_Complex(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 278
    def visit_Complex o
      register o, @emitter.start_mapping(nil, '!ruby/object:Complex', false, Nodes::Mapping::BLOCK)

      ['real', o.real.to_s, 'image', o.imag.to_s].each do |m|
        @emitter.scalar m, nil, nil, true, false, Nodes::Scalar::ANY
      end

      @emitter.end_mapping
    end

visit_Date(o)
Alias for: visit_Integer
visit_DateTime(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 250
    def visit_DateTime o
      formatted = if o.offset.zero?
                    o.strftime("%Y-%m-%d %H:%M:%S.%9N Z".freeze)
                  else
                    o.strftime("%Y-%m-%d %H:%M:%S.%9N %:z".freeze)
                  end
      tag = '!ruby/object:DateTime'
      register o, @emitter.scalar(formatted, nil, tag, false, false, Nodes::Scalar::ANY)
    end

visit_Encoding(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 175
    def visit_Encoding o
      tag = "!ruby/encoding"
      @emitter.scalar o.name, nil, tag, false, false, Nodes::Scalar::ANY
    end

visit_Exception(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 208
    def visit_Exception o
      tag = ['!ruby/exception', o.class.name].join ':'

      @emitter.start_mapping nil, tag, false, Nodes::Mapping::BLOCK

      {
        'message'   => private_iv_get(o, 'mesg'),
        'backtrace' => private_iv_get(o, 'backtrace'),
      }.each do |k,v|
        next unless v
        @emitter.scalar k, nil, nil, true, false, Nodes::Scalar::ANY
        accept v
      end

      dump_ivars o

      @emitter.end_mapping
    end

visit_FalseClass(o)
Alias for: visit_Integer
visit_Float(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 295
    def visit_Float o
      if o.nan?
        @emitter.scalar '.nan', nil, nil, true, false, Nodes::Scalar::ANY
      elsif o.infinite?
        @emitter.scalar((o.infinite? > 0 ? '.inf' : '-.inf'),
          nil, nil, true, false, Nodes::Scalar::ANY)
      else
        @emitter.scalar o.to_s, nil, nil, true, false, Nodes::Scalar::ANY
      end
    end

visit_Hash(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 380
    def visit_Hash o
      if o.class == ::Hash
        register(o, @emitter.start_mapping(nil, nil, true, Psych::Nodes::Mapping::BLOCK))
        o.each do |k,v|
          accept k
          accept v
        end
        @emitter.end_mapping
      else
        visit_hash_subclass o
      end
    end

visit_Integer(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 288
    def visit_Integer o
      @emitter.scalar o.to_s, nil, nil, true, false, Nodes::Scalar::ANY
    end

Also aliased as: visit_TrueClass, visit_FalseClass, visit_Date
visit_Module(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 362
    def visit_Module o
      raise TypeError, "can't dump anonymous module: #{o}" unless o.name
      register o, @emitter.scalar(o.name, nil, '!ruby/module', false, false, Nodes::Scalar::SINGLE_QUOTED)
    end

visit_NameError(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 227
    def visit_NameError o
      tag = ['!ruby/exception', o.class.name].join ':'

      @emitter.start_mapping nil, tag, false, Nodes::Mapping::BLOCK

      {
        'message'   => o.message.to_s,
        'backtrace' => private_iv_get(o, 'backtrace'),
      }.each do |k,v|
        next unless v
        @emitter.scalar k, nil, nil, true, false, Nodes::Scalar::ANY
        accept v
      end

      dump_ivars o

      @emitter.end_mapping
    end

visit_NilClass(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 414
    def visit_NilClass o
      @emitter.scalar('', nil, 'tag:yaml.org,2002:null', true, false, Nodes::Scalar::ANY)
    end

visit_Object(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 180
    def visit_Object o
      tag = Psych.dump_tags[o.class]
      unless tag
        klass = o.class == Object ? nil : o.class.name
        tag   = ['!ruby/object', klass].compact.join(':')
      end

      map = @emitter.start_mapping(nil, tag, false, Nodes::Mapping::BLOCK)
      register(o, map)

      dump_ivars o
      @emitter.end_mapping
    end

visit_Psych_Omap(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 167
    def visit_Psych_Omap o
      seq = @emitter.start_sequence(nil, 'tag:yaml.org,2002:omap', false, Nodes::Sequence::BLOCK)
      register(o, seq)

      o.each { |k,v| visit_Hash k => v }
      @emitter.end_sequence
    end

visit_Psych_Set(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 393
    def visit_Psych_Set o
      register(o, @emitter.start_mapping(nil, '!set', false, Psych::Nodes::Mapping::BLOCK))

      o.each do |k,v|
        accept k
        accept v
      end

      @emitter.end_mapping
    end

visit_Range(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 372
    def visit_Range o
      register o, @emitter.start_mapping(nil, '!ruby/range', false, Nodes::Mapping::BLOCK)
      ['begin', o.begin, 'end', o.end, 'excl', o.exclude_end?].each do |m|
        accept m
      end
      @emitter.end_mapping
    end

visit_Rational(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 265
    def visit_Rational o
      register o, @emitter.start_mapping(nil, '!ruby/object:Rational', false, Nodes::Mapping::BLOCK)

      [
        'denominator', o.denominator.to_s,
        'numerator', o.numerator.to_s
      ].each do |m|
        @emitter.scalar m, nil, nil, true, false, Nodes::Scalar::ANY
      end

      @emitter.end_mapping
    end

visit_Regexp(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 246
    def visit_Regexp o
      register o, @emitter.scalar(o.inspect, nil, '!ruby/regexp', false, false, Nodes::Scalar::ANY)
    end

visit_String(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 310
    def visit_String o
      plain = true
      quote = true
      style = Nodes::Scalar::PLAIN
      tag   = nil

      if binary?(o)
        o     = [o].pack('m0')
        tag   = '!binary' # FIXME: change to below when syck is removed
        #tag   = 'tag:yaml.org,2002:binary'
        style = Nodes::Scalar::LITERAL
        plain = false
        quote = false
      elsif o =~ /\n(?!\Z)/  # match \n except blank line at the end of string
        style = Nodes::Scalar::LITERAL
      elsif o == '<<'
        style = Nodes::Scalar::SINGLE_QUOTED
        tag   = 'tag:yaml.org,2002:str'
        plain = false
        quote = false
      elsif @line_width && o.length > @line_width
        style = Nodes::Scalar::FOLDED
      elsif o =~ /^[^[:word:]][^"]*$/
        style = Nodes::Scalar::DOUBLE_QUOTED
      elsif not String === @ss.tokenize(o) or /\A0[0-7]*[89]/ =~ o
        style = Nodes::Scalar::SINGLE_QUOTED
      end

      is_primitive = o.class == ::String
      ivars = find_ivars o, is_primitive

      if ivars.empty?
        unless is_primitive
          tag = "!ruby/string:#{o.class}"
          plain = false
          quote = false
        end
        @emitter.scalar o, nil, tag, plain, quote, style
      else
        maptag = '!ruby/string'
        maptag << ":#{o.class}" unless o.class == ::String

        register o, @emitter.start_mapping(nil, maptag, false, Nodes::Mapping::BLOCK)
        @emitter.scalar 'str', nil, nil, true, false, Nodes::Scalar::ANY
        @emitter.scalar o, nil, tag, plain, quote, style

        dump_ivars o

        @emitter.end_mapping
      end
    end

visit_Struct(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 194
    def visit_Struct o
      tag = ['!ruby/struct', o.class.name].compact.join(':')

      register o, @emitter.start_mapping(nil, tag, false, Nodes::Mapping::BLOCK)
      o.members.each do |member|
        @emitter.scalar member.to_s, nil, nil, true, false, Nodes::Scalar::ANY
        accept o[member]
      end

      dump_ivars o

      @emitter.end_mapping
    end

visit_Symbol(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 418
    def visit_Symbol o
      if o.empty?
        @emitter.scalar "", nil, '!ruby/symbol', false, false, Nodes::Scalar::ANY
      else
        @emitter.scalar ":#{o}", nil, nil, true, false, Nodes::Scalar::ANY
      end
    end

visit_Time(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 260
    def visit_Time o
      formatted = format_time o
      register o, @emitter.scalar(formatted, nil, nil, true, false, Nodes::Scalar::ANY)
    end

visit_TrueClass(o)
Alias for: visit_Integer

### Private Instance Methods

binary?(string) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 444
    def binary? string
      (string.encoding == Encoding::ASCII_8BIT && !string.ascii_only?) ||
        string.index(NULL) ||
        string.count(BINARY_RANGE, WS_RANGE).fdiv(string.length) > 0.3
    end

dump_coder(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 553
    def dump_coder o
      @coders << o
      tag = Psych.dump_tags[o.class]
      unless tag
        klass = o.class == Object ? nil : o.class.name
        tag   = ['!ruby/object', klass].compact.join(':')
      end

      c = Psych::Coder.new(tag)
      o.encode_with(c)
      emit_coder c, o
    end

dump_ivars(target) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 588
    def dump_ivars target
      ivars = find_ivars target

      ivars.each do |iv|
        @emitter.scalar("#{iv.to_s.sub(/^@/, '')}", nil, nil, true, false, Nodes::Scalar::ANY)
        accept target.instance_variable_get(iv)
      end
    end

dump_list(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 519
    def dump_list o
    end

emit_coder(c, o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 566
    def emit_coder c, o
      case c.type
      when :scalar
        @emitter.scalar c.scalar, nil, c.tag, c.tag.nil?, false, Nodes::Scalar::ANY
      when :seq
        @emitter.start_sequence nil, c.tag, c.tag.nil?, Nodes::Sequence::BLOCK
        c.seq.each do |thing|
          accept thing
        end
        @emitter.end_sequence
      when :map
        register o, @emitter.start_mapping(nil, c.tag, c.implicit, c.style)
        c.map.each do |k,v|
          accept k
          accept v
        end
        @emitter.end_mapping
      when :object
        accept c.object
      end
    end

find_ivars(target, is_primitive=false) click to toggle source

FIXME: remove this method once “to_yaml_properties” is removed

    # File lib/psych/visitors/yaml_tree.rb, line 531
    def find_ivars target, is_primitive=false
      begin
        loc = target.method(:to_yaml_properties).source_location.first
        unless loc.start_with?(Psych::DEPRECATED) || loc.end_with?('rubytypes.rb')
          if $VERBOSE
            warn "#{loc}: to_yaml_properties is deprecated, please implement \"encode_with(coder)\""
          end
          return target.to_yaml_properties
        end
      rescue
        # public_method or source_location might be overridden,
        # and it's OK to skip it since it's only to emit a warning.
      end

      is_primitive ? [] : target.instance_variables
    end

format_time(time) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 522
    def format_time time
      if time.utc?
        time.strftime("%Y-%m-%d %H:%M:%S.%9N Z")
      else
        time.strftime("%Y-%m-%d %H:%M:%S.%9N %:z")
      end
    end

private_iv_get(target, prop) click to toggle source

Get the private instance variable `prop` from `target`

    static VALUE private_iv_get(VALUE self, VALUE target, VALUE prop)
    {
        return rb_attr_get(target, rb_intern(StringValuePtr(prop)));
    }

register(target, yaml_obj) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 548
    def register target, yaml_obj
      @st.register target, yaml_obj
      yaml_obj
    end

visit_array_subclass(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 450
    def visit_array_subclass o
      tag = "!ruby/array:#{o.class}"
      ivars = o.instance_variables
      if ivars.empty?
        node = @emitter.start_sequence(nil, tag, false, Nodes::Sequence::BLOCK)
        register o, node
        o.each { |c| accept c }
        @emitter.end_sequence
      else
        node = @emitter.start_mapping(nil, tag, false, Nodes::Sequence::BLOCK)
        register o, node

        # Dump the internal list
        accept 'internal'
        @emitter.start_sequence(nil, nil, true, Nodes::Sequence::BLOCK)
        o.each { |c| accept c }
        @emitter.end_sequence

        # Dump the ivars
        accept 'ivars'
        @emitter.start_mapping(nil, nil, true, Nodes::Sequence::BLOCK)
        ivars.each do |ivar|
          accept ivar
          accept o.instance_variable_get ivar
        end
        @emitter.end_mapping

        @emitter.end_mapping
      end
    end

visit_hash_subclass(o) click to toggle source

    # File lib/psych/visitors/yaml_tree.rb, line 481
    def visit_hash_subclass o
      ivars = o.instance_variables
      if ivars.any?
        tag = "!ruby/hash-with-ivars:#{o.class}"
        node = @emitter.start_mapping(nil, tag, false, Psych::Nodes::Mapping::BLOCK)
        register(o, node)

        # Dump the elements
        accept 'elements'
        @emitter.start_mapping nil, nil, true, Nodes::Mapping::BLOCK
        o.each do |k,v|
          accept k
          accept v
        end
        @emitter.end_mapping

        # Dump the ivars
        accept 'ivars'
        @emitter.start_mapping nil, nil, true, Nodes::Mapping::BLOCK
        o.instance_variables.each do |ivar|
          accept ivar
          accept o.instance_variable_get ivar
        end
        @emitter.end_mapping

        @emitter.end_mapping
      else
        tag = "!ruby/hash:#{o.class}"
        node = @emitter.start_mapping(nil, tag, false, Psych::Nodes::Mapping::BLOCK)
        register(o, node)
        o.each do |k,v|
          accept k
          accept v
        end
        @emitter.end_mapping
      end
    end