class Psych::TreeBuilder

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.

Attributes

root [R]

Returns the root node for the built tree

Public Class 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

Public Instance 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