YAML event parser class. This class parses a YAML document and calls events on the handler that is passed to the constructor. The events can be used for things such as constructing a YAML AST or deserializing YAML documents. It can even be fed back to Psych::Emitter to emit the same document that was parsed.

See Psych::Handler for documentation on the events that Psych::Parser emits.

Here is an example that prints out ever scalar found in a YAML document:

# Handler for detecting scalar values
class ScalarHandler < Psych::Handler
  def scalar value, anchor, tag, plain, quoted, style
    puts value
  end
end

parser = Psych::Parser.new(ScalarHandler.new)
parser.parse(yaml_document)

Here is an example that feeds the parser back in to Psych::Emitter. The YAML document is read from STDIN and written back out to STDERR:

parser = Psych::Parser.new(Psych::Emitter.new($stderr))
parser.parse($stdin)

Psych uses Psych::Parser in combination with Psych::TreeBuilder to construct an AST of the parsed YAML document.

Namespace
Methods
N
Attributes
[W] external_encoding

Set the encoding for this parser to encoding

[RW] handler

The handler on which events will be called

Class Public methods
new(handler = Handler.new)

Creates a new Psych::Parser instance with handler. YAML events will be called on handler. See Psych::Parser for more details.

# File ext/psych/lib/psych/parser.rb, line 47
def initialize handler = Handler.new
  @handler = handler
  @external_encoding = ANY
end