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()
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Create a new TreeBuilder
instance
# File ext/psych/lib/psych/tree_builder.rb, line 22 def initialize @stack = [] @last = nil @root = nil end
Public Instance Methods
alias(anchor)
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# File ext/psych/lib/psych/tree_builder.rb, line 81 def alias anchor @last.children << Nodes::Alias.new(anchor) end
end_document(implicit_end = !streaming?)
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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 61 def end_document implicit_end = !streaming? @last.implicit_end = implicit_end pop end
end_stream()
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# File ext/psych/lib/psych/tree_builder.rb, line 71 def end_stream pop end
scalar(value, anchor, tag, plain, quoted, style)
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# File ext/psych/lib/psych/tree_builder.rb, line 75 def scalar value, anchor, tag, plain, quoted, style s = Nodes::Scalar.new(value,anchor,tag,plain,quoted,style) @last.children << s s end
start_document(version, tag_directives, implicit)
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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 50 def start_document version, tag_directives, implicit n = Nodes::Document.new version, tag_directives, implicit @last.children << n push n end
start_stream(encoding)
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# File ext/psych/lib/psych/tree_builder.rb, line 66 def start_stream encoding @root = Nodes::Stream.new(encoding) push @root end
Private Instance Methods
pop()
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# File ext/psych/lib/psych/tree_builder.rb, line 91 def pop x = @stack.pop @last = @stack.last x end
push(value)
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# File ext/psych/lib/psych/tree_builder.rb, line 86 def push value @stack.push value @last = value end