Support for the Ruby 2.4 series has ended. See here for reference.
This class works in conjunction with Psych::Parser to build an in-memory parse tree that represents a YAML document.
parser = Psych::Parser.new Psych::TreeBuilder.new parser.parse('--- foo') tree = parser.handler.root
See Psych::Handler for documentation on the event methods used in this class.
Create a new TreeBuilder instance
 
               # File psych/lib/psych/tree_builder.rb, line 22
def initialize
  @stack = []
  @last  = nil
  @root  = nil
end
             
             
               # File psych/lib/psych/tree_builder.rb, line 81
def alias anchor
  @last.children << Nodes::Alias.new(anchor)
end
             
            Handles end_document events with version, tag_directives, and implicit styling.
See Psych::Handler#start_document
 
               # File psych/lib/psych/tree_builder.rb, line 61
def end_document implicit_end = !streaming?
  @last.implicit_end = implicit_end
  pop
end
             
             
               # File psych/lib/psych/tree_builder.rb, line 71
def end_stream
  pop
end
             
             
               # File psych/lib/psych/tree_builder.rb, line 75
def scalar value, anchor, tag, plain, quoted, style
  s = Nodes::Scalar.new(value,anchor,tag,plain,quoted,style)
  @last.children << s
  s
end
             
            Handles start_document events with version, tag_directives, and implicit styling.
See Psych::Handler#start_document
 
               # File psych/lib/psych/tree_builder.rb, line 50
def start_document version, tag_directives, implicit
  n = Nodes::Document.new version, tag_directives, implicit
  @last.children << n
  push n
end