Class: Psych::Visitors::YAMLTree

Inherits:
Visitor show all
Defined in:
lib/psych/visitors/yaml_tree.rb,
ext/psych/yaml_tree.c

Overview

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

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

Direct Known Subclasses

Stream, JSONTree

Instance Attribute Summary

Attributes inherited from Visitor

#finished, #started

Instance Method Summary collapse

Constructor Details

#initialize(options = {}, emitter = Psych::TreeBuilder.new) ⇒ YAMLTree

Returns a new instance of YAMLTree.



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# File 'lib/psych/visitors/yaml_tree.rb', line 11

def initialize options = {}, emitter = Psych::TreeBuilder.new
  super()
  @emitter  = emitter
  @st       = {}
  @ss       = ScalarScanner.new

  @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

Instance Method Details

#accept(target) ⇒ Object 



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# File 'lib/psych/visitors/yaml_tree.rb', line 52

def accept target
  # return any aliases we find
  if node = @st[target.object_id]
    node.anchor = target.object_id.to_s
    return @emitter.alias target.object_id.to_s
  end

  if target.respond_to?(:to_yaml)
    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
  end

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

#finish ⇒ Object 



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# File 'lib/psych/visitors/yaml_tree.rb', line 34

def finish
  @emitter.end_stream.tap do
    @finished = true
  end
end

#push(object) ⇒ Object Also known as: << 



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# File 'lib/psych/visitors/yaml_tree.rb', line 44

def push object
  start unless started?
  @emitter.start_document [], [], false
  accept object
  @emitter.end_document
end

#start(encoding = Nodes::Stream::UTF8) ⇒ Object 



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# File 'lib/psych/visitors/yaml_tree.rb', line 28

def start encoding = Nodes::Stream::UTF8
  @emitter.start_stream(encoding).tap do
    @started = true
  end
end

#tree ⇒ Object 



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# File 'lib/psych/visitors/yaml_tree.rb', line 40

def tree
  finish unless finished?
end

#visit_Array(o) ⇒ Object 



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# File 'lib/psych/visitors/yaml_tree.rb', line 256

def visit_Array o
  register o, @emitter.start_sequence(nil, nil, true, Nodes::Sequence::BLOCK)
  o.each { |c| accept c }
  @emitter.end_sequence
end

#visit_Class(o) ⇒ Object

Raises:

  • (TypeError) 


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# File 'lib/psych/visitors/yaml_tree.rb', line 222

def visit_Class o
  raise TypeError, "can't dump anonymous class #{o.class}"
end

#visit_Complex(o) ⇒ Object 



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# File 'lib/psych/visitors/yaml_tree.rb', line 162

def visit_Complex 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_DateTime(o) ⇒ Object 



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# File 'lib/psych/visitors/yaml_tree.rb', line 138

def visit_DateTime o
  formatted = format_time o.to_time
  tag = '!ruby/object:DateTime'
  @emitter.scalar formatted, nil, tag, false, false, Nodes::Scalar::ANY
end

#visit_Exception(o) ⇒ Object 



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# File 'lib/psych/visitors/yaml_tree.rb', line 115

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_Float(o) ⇒ Object 



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# File 'lib/psych/visitors/yaml_tree.rb', line 179

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) ⇒ Object 



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# File 'lib/psych/visitors/yaml_tree.rb', line 234

def visit_Hash o
  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
end

#visit_Integer(o) ⇒ Object Also known as: visit_TrueClass, visit_FalseClass, visit_Date 



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# File 'lib/psych/visitors/yaml_tree.rb', line 172

def visit_Integer o
  @emitter.scalar o.to_s, nil, nil, true, false, Nodes::Scalar::ANY
end

#visit_NilClass(o) ⇒ Object 



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# File 'lib/psych/visitors/yaml_tree.rb', line 262

def visit_NilClass o
  @emitter.scalar('', nil, 'tag:yaml.org,2002:null', false, false, Nodes::Scalar::ANY)
end

#visit_Object(o) ⇒ Object 



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# File 'lib/psych/visitors/yaml_tree.rb', line 87

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) ⇒ Object 



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# File 'lib/psych/visitors/yaml_tree.rb', line 79

def visit_Psych_Omap o
  seq = @emitter.start_sequence(nil, '!omap', false, Nodes::Sequence::BLOCK)
  register(o, seq)

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

#visit_Psych_Set(o) ⇒ Object 



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# File 'lib/psych/visitors/yaml_tree.rb', line 245

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) ⇒ Object 



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# File 'lib/psych/visitors/yaml_tree.rb', line 226

def visit_Range 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) ⇒ Object 



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# File 'lib/psych/visitors/yaml_tree.rb', line 149

def visit_Rational 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) ⇒ Object 



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# File 'lib/psych/visitors/yaml_tree.rb', line 134

def visit_Regexp o
  @emitter.scalar o.inspect, nil, '!ruby/regexp', false, false, Nodes::Scalar::ANY
end

#visit_String(o) ⇒ Object 



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# File 'lib/psych/visitors/yaml_tree.rb', line 190

def visit_String o
  plain = false
  quote = false
  style = Nodes::Scalar::ANY

  if o.index("\x00") || o.count("^ -~\t\r\n").fdiv(o.length) > 0.3
    str   = [o].pack('m').chomp
    tag   = '!binary' # FIXME: change to below when syck is removed
    #tag   = 'tag:yaml.org,2002:binary'
    style = Nodes::Scalar::LITERAL
  else
    str   = o
    tag   = nil
    quote = !(String === @ss.tokenize(o))
    plain = !quote
  end

  ivars = find_ivars o

  if ivars.empty?
    @emitter.scalar str, nil, tag, plain, quote, style
  else
    @emitter.start_mapping nil, '!str', false, Nodes::Mapping::BLOCK
    @emitter.scalar 'str', nil, nil, true, false, Nodes::Scalar::ANY
    @emitter.scalar str, nil, tag, plain, quote, style

    dump_ivars o

    @emitter.end_mapping
  end
end

#visit_Struct(o) ⇒ Object 



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# File 'lib/psych/visitors/yaml_tree.rb', line 101

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) ⇒ Object 



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# File 'lib/psych/visitors/yaml_tree.rb', line 266

def visit_Symbol o
  @emitter.scalar ":#{o}", nil, nil, true, false, Nodes::Scalar::ANY
end

#visit_Time(o) ⇒ Object 



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# File 'lib/psych/visitors/yaml_tree.rb', line 144

def visit_Time o
  formatted = format_time o
  @emitter.scalar formatted, nil, nil, true, false, Nodes::Scalar::ANY
end