class Psych::TreeBuilder

class.
See Psych::Handler for documentation on the event methods used in this
tree = parser.handler.root
parser.parse(‘— foo’)
parser = Psych::Parser.new Psych::TreeBuilder.new
== Example
parse tree that represents a YAML document.
This class works in conjunction with Psych::Parser to build an in-memory
##

def alias anchor 

def alias anchor
  a = Nodes::Alias.new(anchor)
  set_location(a)
  @last.children << a
  a
end

def end_document implicit_end = !streaming?

See Psych::Handler#start_document

and +implicit+ styling.
Handles end_document events with +version+, +tag_directives+,
## 
def end_document implicit_end = !streaming?
  @last.implicit_end = implicit_end
  n = pop
  set_end_location(n)
  n
end

def end_stream 

def end_stream
  n = pop
  set_end_location(n)
  n
end

def event_location(start_line, start_column, end_line, end_column) 

def event_location(start_line, start_column, end_line, end_column)
  @start_line   = start_line
  @start_column = start_column
  @end_line     = end_line
  @end_column   = end_column
end

def initialize

Create a new TreeBuilder instance 
def initialize
  @stack = []
  @last  = nil
  @root  = nil
  @start_line   = nil
  @start_column = nil
  @end_line     = nil
  @end_column   = nil
end

def pop 

def pop
  x = @stack.pop
  @last = @stack.last
  x
end

def push value 

def push value
  @stack.push value
  @last = value
end

def scalar value, anchor, tag, plain, quoted, style 

def scalar value, anchor, tag, plain, quoted, style
  s = Nodes::Scalar.new(value,anchor,tag,plain,quoted,style)
  set_location(s)
  @last.children << s
  s
end

def set_end_location(node) 

def set_end_location(node)
  node.end_line   = @end_line
  node.end_column = @end_column
end

def set_location(node) 

def set_location(node)
  set_start_location(node)
  set_end_location(node)
end

def set_start_location(node) 

def set_start_location(node)
  node.start_line   = @start_line
  node.start_column = @start_column
end

def start_document version, tag_directives, implicit

See Psych::Handler#start_document

and +implicit+ styling.
Handles start_document events with +version+, +tag_directives+,
## 
def start_document version, tag_directives, implicit
  n = Nodes::Document.new version, tag_directives, implicit
  set_start_location(n)
  @last.children << n
  push n
end

def start_stream encoding 

def start_stream encoding
  @root = Nodes::Stream.new(encoding)
  set_start_location(@root)
  push @root
end