类 Psych::TreeBuilder

此类与 Psych::Parser 协同工作，构建一个内存中的解析树，表示一个 YAML 文档。

示例¶ ↑

parser = Psych::Parser.new Psych::TreeBuilder.new
parser.parse('--- foo')
tree = parser.handler.root

有关此类中使用的事件方法的文档，请参阅 Psych::Handler。

属性

root[R]

返回构建树的根节点

公共类方法

new() 点击切换源代码

创建一个新的 TreeBuilder 实例

# 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

公共实例方法

alias(anchor) 点击切换源代码

# 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?) 点击切换源代码

使用 version、tag_directives 和 implicit 样式处理 end_document 事件。

参见 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() 点击切换源代码

# 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) 点击切换源代码

# 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) 点击切换源代码

# 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) 点击切换源代码

使用 version、tag_directives 和 implicit 样式处理 start_document 事件。

参见 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) 点击切换源代码

# 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

私有实例方法

pop() 点击切换源代码

# File ext/psych/lib/psych/tree_builder.rb, line 116
def pop
  x = @stack.pop
  @last = @stack.last
  x
end

push(value) 点击切换源代码

# File ext/psych/lib/psych/tree_builder.rb, line 111
def push value
  @stack.push value
  @last = value
end

set_end_location(node) 点击切换源代码

# File ext/psych/lib/psych/tree_builder.rb, line 132
def set_end_location(node)
  node.end_line   = @end_line
  node.end_column = @end_column
end

set_location(node) 点击切换源代码

# File ext/psych/lib/psych/tree_builder.rb, line 122
def set_location(node)
  set_start_location(node)
  set_end_location(node)
end

set_start_location(node) 点击切换源代码

# File ext/psych/lib/psych/tree_builder.rb, line 127
def set_start_location(node)
  node.start_line   = @start_line
  node.start_column = @start_column
end