# frozen_string_literal: true
module Psych
###
# 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.
class Parser
class Mark < Struct.new(:index, :line, :column)
end
# The handler on which events will be called
attr_accessor :handler
# Set the encoding for this parser to +encoding+
attr_writer :external_encoding
###
# Creates a new Psych::Parser instance with +handler+. YAML events will
# be called on +handler+. See Psych::Parser for more details.
def initialize handler = Handler.new
@handler = handler
@external_encoding = ANY
end
###
# call-seq:
# parser.parse(yaml)
#
# Parse the YAML document contained in +yaml+. Events will be called on
# the handler set on the parser instance.
#
# See Psych::Parser and Psych::Parser#handler
def parse yaml, path = yaml.respond_to?(:path) ? yaml.path : "<unknown>"
_native_parse @handler, yaml, path
end
end
end
|