OptionParser::Switch::OptionalArgument#parse

parse(arg, argv, &error)

# File tmp/rubies/ruby-3.3.0/lib/optparse.rb, line 754
def parse(arg, argv, &error)
  if arg
    conv_arg(*parse_arg(arg, &error))
  else
    conv_arg(arg)
  end
end

Parses argument if given, or uses default value.

also in 4.1 · 4.0 · 3.4 · 3.2 · 3.1 · 3.0