Method: EBNF::ISOEBNF#initialize

Defined in:
lib/ebnf/isoebnf.rb

#initialize(input, **options, &block) ⇒ EBNFParser

## Parser invocation. On start, yield ourselves if a block is given, otherwise, return this parser instance

Parameters:

  • input (#read, #to_s)
  • options (Hash{Symbol => Object})

Options Hash (**options):

  • :level (Boolean) —

    Trace level. 0(debug), 1(info), 2(warn), 3(error).



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# File 'lib/ebnf/isoebnf.rb', line 197

def initialize(input, **options, &block)
  # If the `level` option is set, instantiate a logger for collecting trace information.
  if options.has_key?(:level)
    options[:logger] = Logger.new(STDERR)
    options[:logger].level = options[:level]
    options[:logger].formatter = lambda {|severity, datetime, progname, msg| "#{severity} #{msg}\n"}
  end

  # Read input, if necessary, which will be used in a Scanner.
  @input = input.respond_to?(:read) ? input.read : input.to_s

  parsing_terminals = false
  @ast = []
  parse(@input,
        :syntax,
        ISOEBNFMeta::RULES,
        whitespace: %r{([\x09-\x0d\x20]|(?:\(\*(?:(?:\*[^\)])|[^*])*\*\)))+},
        **options
  ) do |context, *data|
    rule = case context
    when :rule
      # A rule which has already been turned into a `Rule` object.
      rule = data.first
      rule.kind = :terminal if parsing_terminals
      rule
    end
    @ast << rule if rule
  end
rescue EBNF::PEG::Parser::Error => e
  raise SyntaxError, e.message
end