This class works in conjunction with Psych::Parser to build an in-memory parse tree that represents a YAML document.

Example

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.

Methods
A
E
N
S
Attributes
[R] root

Returns the root node for the built tree

Class Public methods
new()

Create a new TreeBuilder instance

# File ext/psych/lib/psych/tree_builder.rb, line 22
def initialize
  @stack = []
  @last  = nil
  @root  = nil

  @start_line   = nil
  @start_column = nil
  @end_line     = nil
  @end_column   = nil
end
Instance Public methods
alias(anchor)
# File ext/psych/lib/psych/tree_builder.rb, line 103
def alias anchor
  a = Nodes::Alias.new(anchor)
  set_location(a)
  @last.children << a
  a
end
end_document(implicit_end = !streaming?)

Handles #end_document events with version, tag_directives, and implicit styling.

See Psych::Handler#start_document

# File ext/psych/lib/psych/tree_builder.rb, line 77
def end_document implicit_end = !streaming?
  @last.implicit_end = implicit_end
  n = pop
  set_end_location(n)
  n
end
end_stream()
# File ext/psych/lib/psych/tree_builder.rb, line 90
def end_stream
  n = pop
  set_end_location(n)
  n
end
event_location(start_line, start_column, end_line, end_column)
# File ext/psych/lib/psych/tree_builder.rb, line 33
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
scalar(value, anchor, tag, plain, quoted, style)
# File ext/psych/lib/psych/tree_builder.rb, line 96
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
start_document(version, tag_directives, implicit)

Handles #start_document events with version, tag_directives, and implicit styling.

See Psych::Handler#start_document

# File ext/psych/lib/psych/tree_builder.rb, line 65
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
start_stream(encoding)
# File ext/psych/lib/psych/tree_builder.rb, line 84
def start_stream encoding
  @root = Nodes::Stream.new(encoding)
  set_start_location(@root)
  push @root
end