Class: Parser::AST::Node

Inherits:
Object
  • Object
show all
Defined in:
lib/synvert/core/node_ext.rb

Overview

Extend Parser::AST::Node. https://github.com/whitequark/parser/blob/master/lib/parser/ast/node.rb

Rules

Synvert compares ast nodes with key / value pairs, each ast node has multiple attributes, e.g. receiver, message and arguments, it matches only when all of key / value pairs match.

type: ‘send’, message: :include, arguments: [‘FactoryGirl::Syntax::Methods’]

Synvert does comparison based on the value type

  1. if value is a symbol, then compares ast node value as symbol, e.g. message: :include

  2. if value is a string, then compares ast node original source code, e.g. name: ‘Synvert::Application’

  3. if value is a regexp, then compares ast node original source code, e.g. message: /find_all_by_/

  4. if value is an array, then compares each ast node, e.g. arguments: [‘FactoryGirl::Syntax::Methods’]

  5. if value is nil, then check if ast node is nil, e.g. arguments: [nil]

  6. if value is true or false, then check if ast node is :true or :false, e.g. arguments: [false]

  7. if value is ast, then compare ast node directly, e.g. to_ast: Parser::CurrentRuby.parse(“self.class.serialized_attributes”)

It can also compare nested key / value pairs, like

type: ‘send’, receiver: { type: ‘send’, receiver: { type: ‘send’, message: ‘config’ }, message: ‘active_record’ }, message: ‘identity_map=’

Source Code to Ast Node https://synvert-playground.xinminlabs.com/ruby

Constant Summary collapse

TYPE_CHILDREN = 
{
  and: %i[left_value right_value],
  arg: %i[name],
  begin: %i[body],
  block: %i[caller arguments body],
  blockarg: %i[name],
  const: %i[parent_const name],
  class: %i[name parent_class body],
  csend: %i[receiver message arguments],
  cvasgn: %i[left_value right_value],
  cvar: %i[name],
  def: %i[name arguments body],
  definded?: %i[arguments],
  defs: %i[self name arguments body],
  hash: %i[pairs],
  ivasgn: %i[left_value right_value],
  ivar: %i[name],
  lvar: %i[name],
  lvasgn: %i[left_value right_value],
  masgn: %i[left_value right_value],
  module: %i[name body],
  or: %i[left_value right_value],
  or_asgn: %i[left_value right_value],
  pair: %i[key value],
  restarg: %i[name],
  send: %i[receiver message arguments],
  super: %i[arguments],
  zsuper: %i[]
}

Instance Method Summary collapse

Constructor Details

#initialize(type, children = [], properties = {}) ⇒ Node

Initialize a Node.

It extends Parser::AST::Node and set parent for its child nodes.



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# File 'lib/synvert/core/node_ext.rb', line 65

def initialize(type, children = [], properties = {})
  @mutable_attributes = {}
  super
  # children could be nil for s(:array)
  Array(children).each do |child_node|
    if child_node.is_a?(Parser::AST::Node)
      child_node.parent = self
    end
  end
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method_name, *args, &block) ⇒ Object

Respond key value and source for hash node, e.g.

Examples:

node # s(:hash, s(:pair, s(:sym, :foo), s(:sym, :bar)))
node.foo_value # :bar
node.foo_source # ":bar"


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# File 'lib/synvert/core/node_ext.rb', line 278

def method_missing(method_name, *args, &block)
  if :args == type && children.respond_to?(method_name)
    return children.send(method_name, *args, &block)
  elsif :hash == type && method_name.to_s.include?('_value')
    key = method_name.to_s.sub('_value', '')
    return hash_value(key.to_sym)&.to_value if key?(key.to_sym)
    return hash_value(key.to_s)&.to_value if key?(key.to_s)

    return nil
  elsif :hash == type && method_name.to_s.include?('_source')
    key = method_name.to_s.sub('_source', '')
    return hash_value(key.to_sym)&.to_source if key?(key.to_sym)
    return hash_value(key.to_s)&.to_source if key?(key.to_s)

    return nil
  end

  super
end

Instance Method Details

#arguments ⇒ Array<Parser::AST::Node>

Get arguments of node. It supports :block, :csend, :def, :defined?, :defs and :send nodes.

Examples:

node # s(:send, s(:const, nil, :FactoryGirl), :create, s(:sym, :post), s(:hash, s(:pair, s(:sym, :title), s(:str, "post"))))
node.arguments # [s(:sym, :post), s(:hash, s(:pair, s(:sym, :title), s(:str, "post")))]

Returns:

Raises:



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# File 'lib/synvert/core/node_ext.rb', line 130

def arguments
  case type
  when :def, :block
    children[1].children
  when :defs
    children[2].children
  when :send, :csend
    children[2..-1]
  when :defined?
    children
  else
    raise Synvert::Core::MethodNotSupported, "arguments is not handled for #{debug_info}"
  end
end

#body ⇒ Array<Parser::AST::Node>

Get body of node. It supports :begin, :block, :class, :def, :defs and :module node.

Examples:

node # s(:block, s(:send, s(:const, nil, :RSpec), :configure), s(:args, s(:arg, :config)), s(:send, nil, :include, s(:const, s(:const, nil, :EmailSpec), :Helpers)))
node.body # [s(:send, nil, :include, s(:const, s(:const, nil, :EmailSpec), :Helpers))]

Returns:

Raises:



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# File 'lib/synvert/core/node_ext.rb', line 152

def body
  case type
  when :begin
    children
  when :def, :block, :class, :module
    return [] if children[2].nil?

    :begin == children[2].type ? children[2].body : children[2..-1]
  when :defs
    return [] if children[3].nil?

    :begin == children[3].type ? children[3].body : children[3..-1]
  else
    raise Synvert::Core::MethodNotSupported, "body is not handled for #{debug_info}"
  end
end

#child_node_by_name(child_name) ⇒ Parser::AST::Node

Get child node by the name.

Parameters:

  • child_name (String) —

    name of child node.

Returns:

Raises:



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# File 'lib/synvert/core/node_ext.rb', line 357

def child_node_by_name(child_name)
  direct_child_name, nested_child_name = child_name.to_s.split('.', 2)
  if respond_to?(direct_child_name)
    child_node = send(direct_child_name)

    return child_node.child_node_by_name(nested_child_name) if nested_child_name

    return nil if child_node.nil?

    return child_node if child_node.is_a?(Parser::AST::Node)

    return child_node
  end

  raise Synvert::Core::MethodNotSupported,
        "child_node_by_name is not handled for #{debug_info}, child_name: #{child_name}"
end

#child_node_range(child_name) ⇒ Parser::Source::Range

Get the source range of child node.

Parameters:

  • child_name (String) —

    name of child node.

Returns:

  • (Parser::Source::Range) —

    source range of child node.



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# File 'lib/synvert/core/node_ext.rb', line 379

def child_node_range(child_name)
  case [type, child_name.to_sym]
  when %i[block pipes], %i[def parentheses], %i[defs parentheses]
    Parser::Source::Range.new(
      '(string)',
      arguments.first.loc.expression.begin_pos - 1,
      arguments.last.loc.expression.end_pos + 1
    )
  when %i[block arguments], %i[def arguments], %i[defs arguments]
    Parser::Source::Range.new(
      '(string)',
      arguments.first.loc.expression.begin_pos,
      arguments.last.loc.expression.end_pos
    )
  when %i[class name], %i[def name], %i[defs name]
    loc.name
  when %i[defs dot]
    loc.operator
  when %i[defs self]
    Parser::Source::Range.new('(string)', loc.operator.begin_pos - 'self'.length, loc.operator.begin_pos)
  when %i[send dot], %i[csend dot]
    loc.dot
  when %i[send message], %i[csend message]
    if loc.operator
      Parser::Source::Range.new('(string)', loc.selector.begin_pos, loc.operator.end_pos)
    else
      loc.selector
    end
  when %i[send parentheses], %i[csend parentheses]
    if loc.begin && loc.end
      Parser::Source::Range.new('(string)', loc.begin.begin_pos, loc.end.end_pos)
    end
  else
    direct_child_name, nested_child_name = child_name.to_s.split('.', 2)
    if respond_to?(direct_child_name)
      child_node = send(direct_child_name)

      return child_node.child_node_range(nested_child_name) if nested_child_name

      return nil if child_node.nil?

      if child_node.is_a?(Parser::AST::Node)
        return(
          Parser::Source::Range.new(
            '(string)',
            child_node.loc.expression.begin_pos,
            child_node.loc.expression.end_pos
          )
        )
      end

      # arguments
      return nil if child_node.empty?

      return(
        Parser::Source::Range.new(
          '(string)',
          child_node.first.loc.expression.begin_pos,
          child_node.last.loc.expression.end_pos
        )
      )
    end

    raise Synvert::Core::MethodNotSupported,
          "child_node_range is not handled for #{debug_info}, child_name: #{child_name}"
  end
end

#column ⇒ Integer

Get the column of node.

Returns:

  • (Integer) —

    column.



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# File 'lib/synvert/core/node_ext.rb', line 342

def column
  loc.expression.column
end

#condition ⇒ Parser::AST::Node

Get condition of node. It supports :if node.

Examples:

node # s(:if, s(:defined?, s(:const, nil, :Bundler)), nil, nil)
node.condition # s(:defined?, s(:const, nil, :Bundler))

Returns:

Raises:



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# File 'lib/synvert/core/node_ext.rb', line 176

def condition
  if :if == type
    children[0]
  else
    raise Synvert::Core::MethodNotSupported, "condition is not handled for #{debug_info}"
  end
end

#debug_info ⇒ String

Return the debug info.

Returns:

  • (String) —

    file, line, source and node.



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# File 'lib/synvert/core/node_ext.rb', line 315

def debug_info
  "\n" +
    [
      "file: #{loc.expression.source_buffer.name}",
      "line: #{loc.expression.line}",
      "source: #{to_source}",
      "node: #{inspect}"
    ].join("\n")
end

#filename ⇒ String

Get the file name of node.

Returns:

  • (String) —

    file name.



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# File 'lib/synvert/core/node_ext.rb', line 328

def filename
  loc.expression&.source_buffer.name
end

#hash_value(key) ⇒ Parser::AST::Node

Get :hash value node according to specified key.

Examples:

node # s(:hash, s(:pair, s(:sym, :foo), s(:sym, :bar)))
node.hash_value(:foo) # s(:sym, :bar)

Parameters:

  • key (Symbol, String) —

    value.

Returns:

Raises:



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# File 'lib/synvert/core/node_ext.rb', line 234

def hash_value(key)
  if :hash == type
    value_node = children.find { |pair_node| pair_node.key.to_value == key }
    value_node&.value
  else
    raise Synvert::Core::MethodNotSupported, "hash_value is not handled for #{debug_info}"
  end
end

#key?(key) ⇒ Boolean

Check if :hash node contains specified key.

Examples:

node # s(:hash, s(:pair, s(:sym, :foo), s(:sym, :bar)))
node.key?(:foo) # true

Parameters:

  • key (Symbol, String) —

    value.

Returns:

  • (Boolean) —

    true if specified key exists.

Raises:



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# File 'lib/synvert/core/node_ext.rb', line 219

def key?(key)
  if :hash == type
    children.any? { |pair_node| pair_node.key.to_value == key }
  else
    raise Synvert::Core::MethodNotSupported, "key? is not handled for #{debug_info}"
  end
end

#keys ⇒ Array<Parser::AST::Node>

Get keys of :hash node.

Examples:

node # s(:hash, s(:pair, s(:sym, :foo), s(:sym, :bar)), s(:pair, s(:str, "foo"), s(:str, "bar")))
node.keys # [s(:sym, :foo), s(:str, "foo")]

Returns:

Raises:



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# File 'lib/synvert/core/node_ext.rb', line 190

def keys
  if :hash == type
    children.map { |child| child.children[0] }
  else
    raise Synvert::Core::MethodNotSupported, "keys is not handled for #{debug_info}"
  end
end

#left_value ⇒ Parser::AST::Node

Return the left value of node. It supports :and, :cvagn, :lvasgn, :masgn, :or and :or_asgn nodes.

Examples:

node # s(:or_asgn, s(:lvasgn, :a), s(:int, 1))
node.left_value # :a

Returns:

Raises:



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# File 'lib/synvert/core/node_ext.rb', line 114

def left_value
  return children[0].children[0] if type == :or_asgn

  index = TYPE_CHILDREN[type]&.index(:left_value)
  return children[index] if index

  raise Synvert::Core::MethodNotSupported, "#{left_value} is not handled for #{debug_info}"
end

#line ⇒ Integer

Get the line of node.

Returns:

  • (Integer) —

    line.



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# File 'lib/synvert/core/node_ext.rb', line 349

def line
  loc.expression.line
end

#match?(rules) ⇒ Boolean

Match node with rules. It provides some additional keywords to match rules, any, contain, not, in, not_in, gt, gte, lt, lte.

Examples:

type: 'send', arguments: { any: 'Lifo::ShowExceptions' }
type: { in: ['send', 'csend'] }
type: :send, arguments: { length: { gt: 2 } }

Parameters:

  • rules (Hash) —

    rules to match.

Returns:

  • (Boolean) —

    true if matches.



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# File 'lib/synvert/core/node_ext.rb', line 468

def match?(rules)
  keywords = %i[any contain not in not_in gt gte lt lte]
  flat_hash(rules).keys.all? do |multi_keys|
    last_key = multi_keys.last
    actual = keywords.include?(last_key) ? actual_value(multi_keys[0...-1]) : actual_value(multi_keys)
    expected = expected_value(rules, multi_keys)
    case last_key
    when :any, :contain
      actual.any? { |actual_value| match_value?(actual_value, expected) }
    when :not
      !match_value?(actual, expected)
    when :in
      expected.any? { |expected_value| match_value?(actual, expected_value) }
    when :not_in
      expected.all? { |expected_value| !match_value?(actual, expected_value) }
    when :gt
      actual > expected
    when :gte
      actual >= expected
    when :lt
      actual < expected
    when :lte
      actual <= expected
    else
      match_value?(actual, expected)
    end
  end
end

#parent ⇒ Parser::AST::Node

Get the parent node.

Returns:



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# File 'lib/synvert/core/node_ext.rb', line 78

def parent
  @mutable_attributes[:parent]
end

#parent=(node) ⇒ Object

Set the parent node.

Parameters:



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# File 'lib/synvert/core/node_ext.rb', line 84

def parent=(node)
  @mutable_attributes[:parent] = node
end

#recursive_children {|child| ... } ⇒ Object

Recursively iterate all child nodes of node.

Yields:

  • (child) —

    Gives a child node.

Yield Parameters:



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# File 'lib/synvert/core/node_ext.rb', line 451

def recursive_children(&block)
  children.each do |child|
    if child.is_a?(Parser::AST::Node)
      stop = yield child
      child.recursive_children(&block) unless stop == :stop
    end
  end
end

#respond_to_missing?(method_name, *args) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/synvert/core/node_ext.rb', line 298

def respond_to_missing?(method_name, *args)
  if :args == type && children.respond_to?(method_name)
    return true
  elsif :hash == type && method_name.to_s.include?('_value')
    key = method_name.to_s.sub('_value', '')
    return true if key?(key.to_sym) || key?(key.to_s)
  elsif :hash == type && method_name.to_s.include?('_source')
    key = method_name.to_s.sub('_source', '')
    return true if key?(key.to_sym) || key?(key.to_s)
  end

  super
end

#rewritten_source(code) ⇒ String

Get rewritten source code.

Examples:

node.rewritten_source("create({{arguments}})") # "create(:post)"

Parameters:

  • code (String) —

    raw code.

Returns:

  • (String) —

    rewritten code, replace string in block {{ }} in raw code.

Raises:



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# File 'lib/synvert/core/node_ext.rb', line 503

def rewritten_source(code)
  code.gsub(/{{(.*?)}}/m) do
    old_code = Regexp.last_match(1)
    if respond_to?(old_code.split('.').first)
      evaluated = child_node_by_name(old_code)
      case evaluated
      when Parser::AST::Node
        if evaluated.type == :args
          evaluated.loc.expression.source[1...-1]
        else
          evaluated.loc.expression.source
        end
      when Array
        if evaluated.size > 0
          file_source = evaluated.first.loc.expression.source_buffer.source
          source = file_source[evaluated.first.loc.expression.begin_pos...evaluated.last.loc.expression.end_pos]
          lines = source.split "\n"
          lines_count = lines.length
          if lines_count > 1 && lines_count == evaluated.size
            new_code = []
            lines.each_with_index { |line, index|
              new_code << (index == 0 ? line : line[evaluated.first.indent - 2..-1])
            }
            new_code.join("\n")
          else
            source
          end
        end
      when String, Symbol, Integer, Float
        evaluated
      when NilClass
        'nil'
      else
        raise Synvert::Core::MethodNotSupported, "rewritten_source is not handled for #{evaluated.inspect}"
      end
    else
      "{{#{old_code}}}"
    end
  end
end

#siblings ⇒ Array<Parser::AST::Node>

Get the sibling nodes.

Returns:



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# File 'lib/synvert/core/node_ext.rb', line 90

def siblings
  index = parent.children.index(self)
  parent.children[index + 1..]
end

#strip_curly_braces ⇒ String

Strip curly braces for hash.

Examples:

node # s(:hash, s(:pair, s(:sym, :foo), s(:str, "bar")))
node.strip_curly_braces # "foo: 'bar'"

Returns:

  • (String) 


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# File 'lib/synvert/core/node_ext.rb', line 549

def strip_curly_braces
  return to_source unless type == :hash

  to_source.sub(/^{(.*)}$/) { Regexp.last_match(1).strip }
end

#to_hash ⇒ Object

Convert node to a hash, so that it can be converted to a json.



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# File 'lib/synvert/core/node_ext.rb', line 620

def to_hash
  result = { type: type }
  if TYPE_CHILDREN[type]
    TYPE_CHILDREN[type].each do |key|
      value = send(key)
      result[key] =
        case value
        when Array
          value.map { |v| v.respond_to?(:to_hash) ? v.to_hash : v }
        when Parser::AST::Node
          value.to_hash
        else
          value
        end
    end
  else
    result[:children] = children.map { |c| c.respond_to?(:to_hash) ? c.to_hash : c }
  end
  result
end

#to_lambda_literal ⇒ String

Convert lambda {} to -> {}

Examples:

node # s(:block, s(:send, nil, :lambda), s(:args), s(:send, nil, :foobar))
node.to_lambda_literal # "-> { foobar }"

Returns:

  • (String) 


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# File 'lib/synvert/core/node_ext.rb', line 604

def to_lambda_literal
  if type == :block && caller.type == :send && caller.receiver.nil? && caller.message == :lambda
    new_source = to_source
    if arguments.size > 1
      new_source = new_source[0...arguments.first.loc.expression.begin_pos - 2] + new_source[arguments.last.loc.expression.end_pos + 1..-1]
      new_source = new_source.sub('lambda', "->(#{arguments.map(&:to_source).join(', ')})")
    else
      new_source = new_source.sub('lambda', '->')
    end
    new_source
  else
    to_source
  end
end

#to_single_quote ⇒ String

Get single quote string.

Examples:

node # s(:str, "foobar")
node.to_single_quote # "'foobar'"

Returns:

  • (String) 


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# File 'lib/synvert/core/node_ext.rb', line 571

def to_single_quote
  return to_source unless type == :str

  "'#{to_value}'"
end

#to_source ⇒ String

Get the source code of node.

Returns:

  • (String) —

    source code.



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# File 'lib/synvert/core/node_ext.rb', line 335

def to_source
  loc.expression&.source
end

#to_string ⇒ String

Convert symbol to string.

Examples:

node # s(:sym, :foobar)
node.to_string # "foobar"

Returns:

  • (String) 


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# File 'lib/synvert/core/node_ext.rb', line 593

def to_string
  return to_source unless type == :sym

  to_value.to_s
end

#to_symbol ⇒ String

Convert string to symbol.

Examples:

node # s(:str, "foobar")
node.to_symbol # ":foobar"

Returns:

  • (String) 


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# File 'lib/synvert/core/node_ext.rb', line 582

def to_symbol
  return to_source unless type == :str

  ":#{to_value}"
end

#to_value ⇒ Object

Return the exact value of node. It supports :array, :begin, :erange, :false, :float, :irange, :int, :str, :sym and :true nodes.

Examples:

node # s(:array, s(:str, "str"), s(:sym, :str))
node.to_value # ['str', :str]

Returns:

  • (Object) —

    exact value.

Raises:



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# File 'lib/synvert/core/node_ext.rb', line 250

def to_value
  case type
  when :int, :float, :str, :sym
    children.last
  when :true
    true
  when :false
    false
  when :nil
    nil
  when :array
    children.map(&:to_value)
  when :irange
    (children.first.to_value..children.last.to_value)
  when :erange
    (children.first.to_value...children.last.to_value)
  when :begin
    children.first.to_value
  else
    self
  end
end

#values ⇒ Array<Parser::AST::Node>

Get values of :hash node.

Examples:

node # s(:hash, s(:pair, s(:sym, :foo), s(:sym, :bar)), s(:pair, s(:str, "foo"), s(:str, "bar")))
node.values # [s(:sym, :bar), s(:str, "bar")]

Returns:

Raises:



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# File 'lib/synvert/core/node_ext.rb', line 204

def values
  if :hash == type
    children.map { |child| child.children[1] }
  else
    raise Synvert::Core::MethodNotSupported, "keys is not handled for #{debug_info}"
  end
end

#wrap_curly_braces ⇒ String

Wrap curly braces for hash.

Examples:

node # s(:hash, s(:pair, s(:sym, :foo), s(:str, "bar")))
node.wrap_curly_braces # "{ foo: 'bar' }"

Returns:

  • (String) 


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# File 'lib/synvert/core/node_ext.rb', line 560

def wrap_curly_braces
  return to_source unless type == :hash

  "{ #{to_source} }"
end