Class: Psych::TreeBuilder (Ruby 2.7.5)
Description: Class : Psych::TreeBuilder - Ruby 2.7.5

### Home Classes Methods

### In Files

- psych/lib/psych/tree_builder.rb

### Parent

Psych::Handler

### Methods

- ::new
- #alias
- #end_document
- #end_stream
- #event_location
- #scalar
- #start_document
- #start_stream

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# 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() click to toggle source

Create a new `TreeBuilder` instance

                   # File 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) click to toggle source

                   # File 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?) click to toggle source

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

See `Psych::Handler#start_document`

                   # File 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() click to toggle source

                   # File 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) click to toggle source

                   # File 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) click to toggle source

                   # File 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) click to toggle source

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

See `Psych::Handler#start_document`

                   # File 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) click to toggle source

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