Class: Psych::Pure::Emitter

Inherits:

Object

• Object
• Psych::Pure::Emitter

Defined in:

lib/psych/pure.rb

Overview

The emitter is responsible for taking Ruby objects and converting them into YAML documents.

Direct Known Subclasses

SafeEmitter

Defined Under Namespace

Classes: AliasNode, ArrayNode, Formatter, HashNode, NilNode, Node, ObjectNode, OmapNode, SetNode, StringNode, Visitor

Instance Method Summary

• #emit(object) ⇒ Object

  This is the main entrypoint into this object.

• #initialize(io, options) ⇒ Emitter constructor

  Initialize a new emitter with the given io and options.

Constructor Details

#initialize(io, options) ⇒ Emitter

Initialize a new emitter with the given io and options.

# File 'lib/psych/pure.rb', line 4590

def initialize(io, options)
  @io = io || $stdout
  @options = options
  @started = false

  # These three instance variables are used to support dumping repeated
  # objects. When the same object is found more than once, we switch to
  # using an anchor and an alias.
  @object_nodes = {}.compare_by_identity
  @object_anchors = {}.compare_by_identity
  @object_anchor = 0
end

Instance Method Details

#emit(object) ⇒ Object

This is the main entrypoint into this object. It is responsible for pushing a new object onto the emitter, which is then represented as a YAML document.

# File 'lib/psych/pure.rb', line 4606

def emit(object)
  if @started
    @io << "...\n"
  else
    @started = true
  end

  # Very rare circumstance here that there are leading comments attached
  # to the root object of a document that occur before the --- marker. In
  # this case we want to output them first here, then dump the object.
  reload_comments = nil
  if (object.is_a?(LoadedObject) || object.is_a?(LoadedHash)) && (psych_node = object.psych_node).comments? && (leading = psych_node.comments.leading).any?
    leading = [*leading]
    line = psych_node.start_line - 1

    while leading.any? && leading.last.start_line == line
      leading.pop
      line -= 1
    end

    psych_node.comments.leading.slice!(0, leading.length)
    line = nil

    leading.each do |comment|
      if line && (line < comment.start_line)
        @io << "\n" * (comment.start_line - line - 1)
      end

      @io << comment.value
      @io << "\n"

      line = comment.start_line
    end

    reload_comments = leading.concat(psych_node.comments.leading)
  end

  @io << "---"

  if (node = dump(object)).is_a?(NilNode)
    @io << "\n"
  else
    q = Formatter.new(+"", 79, "\n") { |n| " " * n }

    if (node.is_a?(ArrayNode) || node.is_a?(HashNode)) && !node.value.empty?
      q.breakable
    else
      q.text(" ")
    end

    node.accept(Visitor.new(q, sequence_indent: @options.fetch(:sequence_indent, false)))
    q.breakable
    q.current_group.break
    q.flush

    @io << q.output
  end

  # If we initially split up the leading comments, then we need to reload
  # them back to their original state here.
  unless reload_comments.nil?
    object.psych_node.comments.leading.replace(reload_comments)
  end
end