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Object
The GetoptLong class allows you to parse command line options similarly to the GNU getopt_long() C library call. Note, however, that GetoptLong is a pure Ruby implementation.
GetoptLong allows for POSIX-style options
like --file
as well as single letter options like
-f
The empty option --
(two minus symbols) is used to end option
processing. This can be particularly important if options have optional
arguments.
Here is a simple example of usage:
require 'getoptlong' opts = GetoptLong.new( [ '--help', '-h', GetoptLong::NO_ARGUMENT ], [ '--repeat', '-n', GetoptLong::REQUIRED_ARGUMENT ], [ '--name', GetoptLong::OPTIONAL_ARGUMENT ] ) dir = nil name = nil repetitions = 1 opts.each do |opt, arg| case opt when '--help' puts <<-EOF hello [OPTION] ... DIR -h, --help: show help --repeat x, -n x: repeat x times --name [name]: greet user by name, if name not supplied default is John DIR: The directory in which to issue the greeting. EOF when '--repeat' repetitions = arg.to_i when '--name' if arg == '' name = 'John' else name = arg end end end if ARGV.length != 1 puts "Missing dir argument (try --help)" exit 0 end dir = ARGV.shift Dir.chdir(dir) for i in (1..repetitions) print "Hello" if name print ", #{name}" end puts end
Example command line:
hello -n 6 --name -- /tmp
Argument flags.
Orderings.
Set up option processing.
The options to support are passed to new() as an array of arrays. Each sub-array contains any number of String option names which carry the same meaning, and one of the following flags:
Option does not take an argument.
Option always takes an argument.
Option may or may not take an argument.
The first option name is considered to be the preferred (canonical) name. Other than that, the elements of each sub-array can be in any order.
# File getoptlong.rb, line 128 def initialize(*arguments) # # Current ordering. # if ENV.include?('POSIXLY_CORRECT') @ordering = REQUIRE_ORDER else @ordering = PERMUTE end # # Hash table of option names. # Keys of the table are option names, and their values are canonical # names of the options. # @canonical_names = Hash.new # # Hash table of argument flags. # Keys of the table are option names, and their values are argument # flags of the options. # @argument_flags = Hash.new # # Whether error messages are output to $stderr. # @quiet = FALSE # # Status code. # @status = STATUS_YET # # Error code. # @error = nil # # Error message. # @error_message = nil # # Rest of catenated short options. # @rest_singles = '' # # List of non-option-arguments. # Append them to ARGV when option processing is terminated. # @non_option_arguments = Array.new if 0 < arguments.length set_options(*arguments) end end
Iterator version of `get'.
The block is called repeatedly with two arguments: The first is the option name. The second is the argument which followed it (if any). Example: ('–opt', 'value')
The option name is always converted to the first (preferred) name given in the original options to ::new.
# File getoptlong.rb, line 600 def each loop do option_name, option_argument = get_option break if option_name == nil yield option_name, option_argument end end
Return the appropriate error message in POSIX-defined format. If no error has occurred, returns nil.
# File getoptlong.rb, line 411 def error_message return @error_message end
Get next option name and its argument, as an Array of two elements.
The option name is always converted to the first (preferred) name given in the original options to ::new.
Example: ['–option', 'value']
Returns nil if the processing is complete (as determined by STATUS_TERMINATED).
# File getoptlong.rb, line 426 def get option_name, option_argument = nil, '' # # Check status. # return nil if @error != nil case @status when STATUS_YET @status = STATUS_STARTED when STATUS_TERMINATED return nil end # # Get next option argument. # if 0 < @rest_singles.length argument = '-' + @rest_singles elsif (ARGV.length == 0) terminate return nil elsif @ordering == PERMUTE while 0 < ARGV.length && ARGV[0] !~ /^-./ @non_option_arguments.push(ARGV.shift) end if ARGV.length == 0 terminate return nil end argument = ARGV.shift elsif @ordering == REQUIRE_ORDER if (ARGV[0] !~ /^-./) terminate return nil end argument = ARGV.shift else argument = ARGV.shift end # # Check the special argument `--'. # `--' indicates the end of the option list. # if argument == '--' && @rest_singles.length == 0 terminate return nil end # # Check for long and short options. # if argument =~ /^(--[^=]+)/ && @rest_singles.length == 0 # # This is a long style option, which start with `--'. # pattern = $1 if @canonical_names.include?(pattern) option_name = pattern else # # The option `option_name' is not registered in `@canonical_names'. # It may be an abbreviated. # matches = [] @canonical_names.each_key do |key| if key.index(pattern) == 0 option_name = key matches << key end end if 2 <= matches.length set_error(AmbiguousOption, "option `#{argument}' is ambiguous between #{matches.join(', ')}") elsif matches.length == 0 set_error(InvalidOption, "unrecognized option `#{argument}'") end end # # Check an argument to the option. # if @argument_flags[option_name] == REQUIRED_ARGUMENT if argument =~ /=(.*)$/ option_argument = $1 elsif 0 < ARGV.length option_argument = ARGV.shift else set_error(MissingArgument, "option `#{argument}' requires an argument") end elsif @argument_flags[option_name] == OPTIONAL_ARGUMENT if argument =~ /=(.*)$/ option_argument = $1 elsif 0 < ARGV.length && ARGV[0] !~ /^-./ option_argument = ARGV.shift else option_argument = '' end elsif argument =~ /=(.*)$/ set_error(NeedlessArgument, "option `#{option_name}' doesn't allow an argument") end elsif argument =~ /^(-(.))(.*)/ # # This is a short style option, which start with `-' (not `--'). # Short options may be catenated (e.g. `-l -g' is equivalent to # `-lg'). # option_name, ch, @rest_singles = $1, $2, $3 if @canonical_names.include?(option_name) # # The option `option_name' is found in `@canonical_names'. # Check its argument. # if @argument_flags[option_name] == REQUIRED_ARGUMENT if 0 < @rest_singles.length option_argument = @rest_singles @rest_singles = '' elsif 0 < ARGV.length option_argument = ARGV.shift else # 1003.2 specifies the format of this message. set_error(MissingArgument, "option requires an argument -- #{ch}") end elsif @argument_flags[option_name] == OPTIONAL_ARGUMENT if 0 < @rest_singles.length option_argument = @rest_singles @rest_singles = '' elsif 0 < ARGV.length && ARGV[0] !~ /^-./ option_argument = ARGV.shift else option_argument = '' end end else # # This is an invalid option. # 1003.2 specifies the format of this message. # if ENV.include?('POSIXLY_CORRECT') set_error(InvalidOption, "invalid option -- #{ch}") else set_error(InvalidOption, "invalid option -- #{ch}") end end else # # This is a non-option argument. # Only RETURN_IN_ORDER falled into here. # return '', argument end return @canonical_names[option_name], option_argument end
Set the handling of the ordering of options and arguments. A RuntimeError is raised if option processing has already started.
The supplied value must be a member of GetoptLong::ORDERINGS. It alters the processing of options as follows:
REQUIRE_ORDER :
Options are required to occur before non-options.
Processing of options ends as soon as a word is encountered that has not been preceded by an appropriate option flag.
For example, if -a and -b are options which do not take arguments, parsing command line arguments of '-a one -b two' would result in 'one', '-b', 'two' being left in ARGV, and only ('-a', '') being processed as an option/arg pair.
This is the default ordering, if the environment variable POSIXLY_CORRECT is set. (This is for compatibility with GNU getopt_long.)
PERMUTE :
Options can occur anywhere in the command line parsed. This is the default behavior.
Every sequence of words which can be interpreted as an option (with or without argument) is treated as an option; non-option words are skipped.
For example, if -a does not require an argument and -b optionally takes an argument, parsing '-a one -b two three' would result in ('-a','') and ('-b', 'two') being processed as option/arg pairs, and 'one','three' being left in ARGV.
If the ordering is set to PERMUTE but the environment variable POSIXLY_CORRECT is set, REQUIRE_ORDER is used instead. This is for compatibility with GNU getopt_long.
RETURN_IN_ORDER :
All words on the command line are processed as options. Words not preceded by a short or long option flag are passed as arguments with an option of '' (empty string).
For example, if -a requires an argument but -b does not, a command line of '-a one -b two three' would result in option/arg pairs of ('-a', 'one') ('-b', ''), ('', 'two'), ('', 'three') being processed.
# File getoptlong.rb, line 237 def ordering=(ordering) # # The method is failed if option processing has already started. # if @status != STATUS_YET set_error(ArgumentError, "argument error") raise RuntimeError, "invoke ordering=, but option processing has already started" end # # Check ordering. # if !ORDERINGS.include?(ordering) raise ArgumentError, "invalid ordering `#{ordering}'" end if ordering == PERMUTE && ENV.include?('POSIXLY_CORRECT') @ordering = REQUIRE_ORDER else @ordering = ordering end end
Set options. Takes the same argument as ::new.
Raises a RuntimeError if option processing has already started.
# File getoptlong.rb, line 270 def set_options(*arguments) # # The method is failed if option processing has already started. # if @status != STATUS_YET raise RuntimeError, "invoke set_options, but option processing has already started" end # # Clear tables of option names and argument flags. # @canonical_names.clear @argument_flags.clear arguments.each do |arg| if !arg.is_a?(Array) raise ArgumentError, "the option list contains non-Array argument" end # # Find an argument flag and it set to `argument_flag'. # argument_flag = nil arg.each do |i| if ARGUMENT_FLAGS.include?(i) if argument_flag != nil raise ArgumentError, "too many argument-flags" end argument_flag = i end end raise ArgumentError, "no argument-flag" if argument_flag == nil canonical_name = nil arg.each do |i| # # Check an option name. # next if i == argument_flag begin if !i.is_a?(String) || i !~ /^-([^-]|-.+)$/ raise ArgumentError, "an invalid option `#{i}'" end if (@canonical_names.include?(i)) raise ArgumentError, "option redefined `#{i}'" end rescue @canonical_names.clear @argument_flags.clear raise end # # Register the option (`i') to the `@canonical_names' and # `@canonical_names' Hashes. # if canonical_name == nil canonical_name = i end @canonical_names[i] = canonical_name @argument_flags[i] = argument_flag end raise ArgumentError, "no option name" if canonical_name == nil end return self end
Explicitly terminate option processing.
# File getoptlong.rb, line 357 def terminate return nil if @status == STATUS_TERMINATED raise RuntimeError, "an error has occurred" if @error != nil @status = STATUS_TERMINATED @non_option_arguments.reverse_each do |argument| ARGV.unshift(argument) end @canonical_names = nil @argument_flags = nil @rest_singles = nil @non_option_arguments = nil return self end
Set an error (a protected method).
# File getoptlong.rb, line 384 def set_error(type, message) $stderr.print("#{$0}: #{message}\n") if !@quiet @error = type @error_message = message @canonical_names = nil @argument_flags = nil @rest_singles = nil @non_option_arguments = nil raise type, message end