class UserChoices::PosixCommandLineSource

Process command-line choices according to POSIX rules. Consider

ruby copy.rb file1 –odd-file-name

Ordinarily, that’s permuted so that –odd-file-name is expected to be an option or switch, not an argument. One way to make CommandLineSource parsing treat it as an argument is to use a – to signal the end of option parsing:

ruby copy.rb – file1 –odd-file-name

Another is to rely on the user to set environment variable POSIXLY_CORRECT.

Since both of those require the user to do something, they’re error-prone.

Another way is to use this class, which obeys POSIX-standard rules. Under those rules, the first word on the command line that does not begin with a dash marks the end of all options. In that case, the first command line above would parse into two arguments and no options.

Public Instance Methods

fill() click to toggle source

# File lib/user-choices/command-line-source.rb, line 211
def fill
  begin
    already_set = ENV.include?('POSIXLY_CORRECT')
    ENV['POSIXLY_CORRECT'] = 'true' unless already_set
    super
  ensure
    ENV.delete('POSIXLY_CORRECT') unless already_set
  end
end