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 -- /tmpConstants
Argument flags.
Orderings.
Version.
error[R]
Examine whether an option processing is failed.
error?[R]
Examine whether an option processing is failed.
ordering[R]
Return ordering.
quiet[RW]
Set/Unset `quiet' mode.
quiet?[RW]
Set/Unset `quiet' mode.
Public Class Methodsnew(*arguments) click to toggle source
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.
def initialize(*arguments)
if ENV.include?('POSIXLY_CORRECT')
@ordering = REQUIRE_ORDER
else
@ordering = PERMUTE
end
@canonical_names = Hash.new
@argument_flags = Hash.new
@quiet = false
@status = STATUS_YET
@error = nil
@error_message = nil
@rest_singles = ''
@non_option_arguments = Array.new
if 0 < arguments.length
set_options(*arguments)
end
end Public Instance Methods
each() { |option_name, option_argument| ... } click to toggle source
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: ('âopt', 'value')
The option name is always converted to the first (preferred) name given in the original options to GetoptLong.new.
def each
loop do
option_name, option_argument = get_option
break if option_name == nil
yield option_name, option_argument
end
end
each_option()
`each_option' is an alias of `each'.
error_message() click to toggle source
Return the appropriate error message in POSIX-defined format. If no error has occurred, returns nil.
def error_message return @error_message end
get() click to toggle source
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 GetoptLong.new.
Example: ['âoption', 'value']
Returns nil if the processing is complete (as determined by STATUS_TERMINATED).
def get
option_name, option_argument = nil, ''
return nil if @error != nil
case @status
when STATUS_YET
@status = STATUS_STARTED
when STATUS_TERMINATED
return nil
end
if 0 < @rest_singles.length
argument = '-' + @rest_singles
elsif (ARGV.length == 0)
terminate
return nil
elsif @ordering == PERMUTE
while 0 < ARGV.length && ARGV[0] !~ /\A-./
@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] !~ /\A-./)
terminate
return nil
end
argument = ARGV.shift
else
argument = ARGV.shift
end
if argument == '--' && @rest_singles.length == 0
terminate
return nil
end
if argument =~ /\A(--[^=]+)/ && @rest_singles.length == 0
pattern = $1
if @canonical_names.include?(pattern)
option_name = pattern
else
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
if @argument_flags[option_name] == REQUIRED_ARGUMENT
if argument =~ /=(.*)/m
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 =~ /=(.*)/m
option_argument = $1
elsif 0 < ARGV.length && ARGV[0] !~ /\A-./
option_argument = ARGV.shift
else
option_argument = ''
end
elsif argument =~ /=(.*)/m
set_error(NeedlessArgument,
"option `#{option_name}' doesn't allow an argument")
end
elsif argument =~ /\A(-(.))(.*)/m
option_name, ch, @rest_singles = $1, $2, $3
if @canonical_names.include?(option_name)
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
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] !~ /\A-./
option_argument = ARGV.shift
else
option_argument = ''
end
end
else
if ENV.include?('POSIXLY_CORRECT')
set_error(InvalidOption, "invalid option -- #{ch}")
else
set_error(InvalidOption, "invalid option -- #{ch}")
end
end
else
return '', argument
end
return @canonical_names[option_name], option_argument
end
get_option()
`get_option' is an alias of `get'.
ordering=(ordering) click to toggle source
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.
def ordering=(ordering)
if @status != STATUS_YET
set_error(ArgumentError, "argument error")
raise RuntimeError,
"invoke ordering=, but option processing has already started"
end
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(*arguments) click to toggle source
Set options. Takes the same argument as GetoptLong.new.
Raises a RuntimeError if option processing has already started.
def set_options(*arguments)
if @status != STATUS_YET
raise RuntimeError,
"invoke set_options, but option processing has already started"
end
@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
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|
next if i == argument_flag
begin
if !i.is_a?(String) || i !~ /\A-([^-]|-.+)\z/
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
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
terminate() click to toggle source
Explicitly terminate option processing.
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
terminated?() click to toggle source
Returns true if option processing has terminated, false otherwise.
def terminated? return @status == STATUS_TERMINATED endProtected Instance Methods
set_error(type, message) click to toggle source
Set an error (a protected method).
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
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