== Parameters for New Options Option-creating methods in \OptionParser accept arguments that determine the behavior of a new option: - OptionParser#on - OptionParser#on_head - OptionParser#on_tail - OptionParser#define - OptionParser#define_head - OptionParser#define_tail - OptionParser#make_switch The code examples on this page use: - OptionParser#on, to define options. - OptionParser#parse!, to parse the command line. - Built-in option --help, to display defined options. Contents: - {Option Names}[#label-Option+Names] - {Short Names}[#label-Short+Names] - {Simple Short Names}[#label-Simple+Short+Names] - {Short Names with Required Arguments}[#label-Short+Names+with+Required+Arguments] - {Short Names with Optional Arguments}[#label-Short+Names+with+Optional+Arguments] - {Short Names from Range}[#label-Short+Names+from+Range] - {Long Names}[#label-Long+Names] - {Simple Long Names}[#label-Simple+Long+Names] - {Long Names with Required Arguments}[#label-Long+Names+with+Required+Arguments] - {Long Names with Optional Arguments}[#label-Long+Names+with+Optional+Arguments] - {Mixed Names}[#label-Mixed+Names] - {Argument Styles}[#label-Argument+Styles] - {Argument Values}[#label-Argument+Values] - {Explicit Argument Values}[#label-Explicit+Argument+Values] - {Explicit Values in Array}[#label-Explicit+Values+in+Array] - {Explicit Values in Hash}[#label-Explicit+Values+in+Hash] - {Argument Value Patterns}[#label-Argument+Value+Patterns] - {Argument Converters}[#label-Argument+Converters] - {Date}[#label-Date] - {DateTime}[#label-DateTime] - {Time}[#label-Time] - {URI}[#label-URI] - {Shellwords}[#label-Shellwords] - {Integer}[#label-Integer] - {Float}[#label-Float] - {Numeric}[#label-Numeric] - {DecimalInteger}[#label-DecimalInteger] - {OctalInteger}[#label-OctalInteger] - {DecimalNumeric}[#label-DecimalNumeric] - {TrueClass}[#label-TrueClass] - {FalseClass}[#label-FalseClass] - {Object}[#label-Object] - {String}[#label-String] - {Array}[#label-Array] - {Regexp}[#label-Regexp] - {Descriptions}[#label-Descriptions] - {Option Handlers}[#label-Option+Handlers] - {Handler Blocks}[#label-Handler+Blocks] - {Handler Procs}[#label-Handler+Procs] - {Handler Methods}[#label-Handler+Methods] - {Terminators}[#label-Terminators] === Option Names There are two kinds of option names: - Short option name, consisting of a single hyphen and a single character. - Long option name, consisting of two hyphens and one or more characters. ==== Short Names ===== Simple Short Names File +short_simple.rb+ defines two options: - One with short name -x. - The other with two short names, in effect, aliases, -1 and -%. :include: short_simple.rb Executions: $ ruby short_simple.rb --help Usage: short_simple [options] -x One short name -1, -% Two short names (aliases) $ ruby short_simple.rb -x ["-x", true] $ ruby short_simple.rb -1 -x -% ["-1 or -%", true] ["-x", true] ["-1 or -%", true] ===== Short Names with Required Arguments A short name followed (no whitespace) by a dummy word defines an option that requires an argument. File +short_required.rb+ defines an option -x that requires an argument. :include: short_required.rb Executions: $ ruby short_required.rb --help Usage: short_required [options] -xXXX Short name with required argument $ ruby short_required.rb -x short_required.rb:6:in `
': missing argument: -x (OptionParser::MissingArgument) $ ruby short_required.rb -x FOO ["-x", "FOO"] ===== Short Names with Optional Arguments A short name followed (with whitespace) by a dummy word in square brackets defines an option that allows an optional argument. File +short_optional.rb+ defines an option -x that allows an optional argument. :include: short_optional.rb Executions: $ ruby short_optional.rb --help Usage: short_optional [options] -x [XXX] Short name with optional argument $ ruby short_optional.rb -x ["-x", nil] $ ruby short_optional.rb -x FOO ["-x", "FOO"] ===== Short Names from Range You can define an option with multiple short names taken from a range of characters. The parser yields both the actual character cited and the value. File +short_range.rb+ defines an option with short names for all printable characters from ! to ~: :include: short_range.rb Executions: $ ruby short_range.rb --help Usage: short_range [options] -[!-~] Short names in (very large) range $ ruby short_range.rb -! ["!-~", "!", nil] $ ruby short_range.rb -! ["!-~", "!", nil] $ ruby short_range.rb -A ["!-~", "A", nil] $ ruby short_range.rb -z ["!-~", "z", nil] ==== Long Names ===== Simple Long Names File +long_simple.rb+ defines two options: - One with long name -xxx. - The other with two long names, in effect, aliases, --y1% and --z2#. :include: long_simple.rb Executions: $ ruby long_simple.rb --help Usage: long_simple [options] --xxx One long name --y1%, --z2# Two long names (aliases) $ ruby long_simple.rb --xxx ["--xxx", true] $ ruby long_simple.rb --y1% --xxx --z2# ["--y1% or --z2#", true] ["--xxx", true] ["--y1% or --z2#", true] ===== Long Names with Required Arguments A long name followed (with whitespace) by a dummy word defines an option that requires an argument. File +long_required.rb+ defines an option --xxx that requires an argument. :include: long_required.rb Executions: $ ruby long_required.rb --help Usage: long_required [options] --xxx XXX Long name with required argument $ ruby long_required.rb --xxx long_required.rb:6:in `
': missing argument: --xxx (OptionParser::MissingArgument) $ ruby long_required.rb --xxx FOO ["--xxx", "FOO"] ===== Long Names with Optional Arguments A long name followed (with whitespace) by a dummy word in square brackets defines an option that allows an optional argument. File +long_optional.rb+ defines an option --xxx that allows an optional argument. :include: long_optional.rb Executions: $ ruby long_optional.rb --help Usage: long_optional [options] --xxx [XXX] Long name with optional argument $ ruby long_optional.rb --xxx ["--xxx", nil] $ ruby long_optional.rb --xxx FOO ["--xxx", "FOO"] ==== Mixed Names An option may have both short and long names. File +mixed_names.rb+ defines a mixture of short and long names. :include: mixed_names.rb Executions: $ ruby mixed_names.rb --help Usage: mixed_names [options] -x, --xxx Short and long, simple --yyy yYYY Short and long, required argument --zzz zZZZ Short and long, optional argument $ ruby mixed_names.rb -x ["--xxx", true] $ ruby mixed_names.rb --xxx ["--xxx", true] $ ruby mixed_names.rb -y mixed_names.rb:12:in `
': missing argument: -y (OptionParser::MissingArgument) $ ruby mixed_names.rb -y FOO ["--yyy", "FOO"] $ ruby mixed_names.rb --yyy mixed_names.rb:12:in `
': missing argument: --yyy (OptionParser::MissingArgument) $ ruby mixed_names.rb --yyy BAR ["--yyy", "BAR"] $ ruby mixed_names.rb -z ["--zzz", nil] $ ruby mixed_names.rb -z BAZ ["--zzz", "BAZ"] $ ruby mixed_names.rb --zzz ["--zzz", nil] $ ruby mixed_names.rb --zzz BAT ["--zzz", "BAT"] === Argument Keywords As seen above, a given option name string may itself indicate whether the option has no argument, a required argument, or an optional argument. An alternative is to use a separate symbol keyword, which is one of :NONE (the default), :REQUIRED, :OPTIONAL. File +argument_keywords.rb+ defines an option with a required argument. :include: argument_keywords.rb Executions: $ ruby argument_keywords.rb --help Usage: argument_keywords [options] -x, --xxx Required argument $ ruby argument_styles.rb --xxx argument_styles.rb:6:in `
': missing argument: --xxx (OptionParser::MissingArgument) $ ruby argument_styles.rb --xxx FOO ["--xxx", "FOO"] === Argument Strings Still another way to specify a required argument is to define it in a string separate from the name string. File +argument_strings.rb+ defines an option with a required argument. :include: argument_strings.rb Executions: $ ruby argument_strings.rb --help Usage: argument_strings [options] -x, --xxx=XXX Required argument $ ruby argument_strings.rb --xxx argument_strings.rb:9:in `
': missing argument: --xxx (OptionParser::MissingArgument) $ ruby argument_strings.rb --xxx FOO ["--xxx", "FOO"] === Argument Values Permissible argument values may be restricted either by specifying explicit values or by providing a pattern that the given value must match. ==== Explicit Argument Values You can specify argument values in either of two ways: - Specify values an array of strings. - Specify values a hash. ===== Explicit Values in Array You can specify explicit argument values in an array of strings. The argument value must be one of those strings. File +explicit_array_values.rb+ defines options with explicit argument values. :include: explicit_array_values.rb Executions: $ ruby explicit_array_values.rb --help Usage: explicit_array_values [options] -xXXX Values for required argument -y [YYY] Values for optional argument $ ruby explicit_array_values.rb -x explicit_array_values.rb:9:in `
': missing argument: -x (OptionParser::MissingArgument) $ ruby explicit_array_values.rb -x foo ["-x", "foo"] $ ruby explicit_array_values.rb -x bar ["-x", "bar"] $ ruby explicit_array_values.rb -x baz explicit_array_values.rb:9:in `
': invalid argument: -x baz (OptionParser::InvalidArgument) ===== Explicit Values in Hash You can specify explicit argument values in a hash with string keys. The value passed must be one of those keys, and the value yielded will be the value for that key. File +explicit_hash_values.rb+ defines options with explicit argument values. :include: explicit_hash_values.rb Executions: $ ruby explicit_hash_values.rb --help Usage: explicit_hash_values [options] -xXXX Values for required argument -y [YYY] Values for optional argument $ ruby explicit_hash_values.rb -x explicit_hash_values.rb:9:in `
': missing argument: -x (OptionParser::MissingArgument) $ ruby explicit_hash_values.rb -x foo ["-x", 0] $ ruby explicit_hash_values.rb -x bar ["-x", 1] $ ruby explicit_hash_values.rb -x baz explicit_hash_values.rb:9:in `
': invalid argument: -x baz (OptionParser::InvalidArgument) $ ruby explicit_hash_values.rb -y ["-y", nil] $ ruby explicit_hash_values.rb -y baz ["-y", 2] $ ruby explicit_hash_values.rb -y bat ["-y", 3] $ ruby explicit_hash_values.rb -y bam ["-y", nil] ==== Argument Value Patterns You can restrict permissible argument values by specifying a Regexp that the given argument must match. File +matched_values.rb+ defines options with matched argument values. :include: matched_values.rb Executions: $ ruby matched_values.rb --help Usage: matched_values [options] --xxx XXX Matched values $ ruby matched_values.rb --xxx foo ["--xxx", "foo"] $ ruby matched_values.rb --xxx FOO ["--xxx", "FOO"] $ ruby matched_values.rb --xxx bar matched_values.rb:6:in `
': invalid argument: --xxx bar (OptionParser::InvalidArgument) === Argument Converters An option can specify that its argument is to be converted from the default \String to an instance of another class. \OptionParser has a number of built-in converters, which are demonstrated below. ==== \Date File +date.rb+ defines an option whose argument is to be converted to a \Date object. The argument is converted by method {Date.parse}[https://ruby-doc.org/stdlib/libdoc/date/rdoc/Date.html#method-c-parse]. :include: date.rb Executions: $ ruby date.rb --date 2001-02-03 [#, Date] $ ruby date.rb --date 20010203 [#, Date] $ ruby date.rb --date "3rd Feb 2001" [#, Date] ==== \DateTime File +datetime.rb+ defines an option whose argument is to be converted to a \DateTime object. The argument is converted by method {DateTime.parse}[https://ruby-doc.org/stdlib-2.6.1/libdoc/date/rdoc/DateTime.html#method-c-parse]. :include: datetime.rb Executions: $ ruby datetime.rb --datetime 2001-02-03T04:05:06+07:00 [#, DateTime] $ ruby datetime.rb --datetime 20010203T040506+0700 [#, DateTime] $ ruby datetime.rb --datetime "3rd Feb 2001 04:05:06 PM" [#, DateTime] ==== \Time File +time.rb+ defines an option whose argument is to be converted to a \Time object. The argument is converted by method {Time.httpdate}[https://ruby-doc.org/stdlib-2.7.0/libdoc/time/rdoc/Time.html#method-c-httpdate] or {Time.parse}[https://ruby-doc.org/stdlib-2.7.0/libdoc/time/rdoc/Time.html#method-c-parse]. :include: time.rb Executions: $ ruby time.rb --time "Thu, 06 Oct 2011 02:26:12 GMT" [2011-10-06 02:26:12 UTC, Time] $ ruby time.rb --time 2010-10-31 [2010-10-31 00:00:00 -0500, Time] ==== \URI File +uri.rb+ defines an option whose argument is to be converted to a \URI object. The argument is converted by method {URI.parse}[https://ruby-doc.org/stdlib-2.7.2/libdoc/uri/rdoc/URI.html#method-c-parse]. :include: uri.rb Executions: $ ruby uri.rb --uri https://github.com [#, URI::HTTPS] $ ruby uri.rb --uri http://github.com [#, URI::HTTP] $ ruby uri.rb --uri file://~/var [#, URI::File] ==== \Shellwords File +shellwords.rb+ defines an option whose argument is to be converted to an \Array object by method {Shellwords.shellwords}[https://ruby-doc.org/stdlib-2.7.0/libdoc/shellwords/rdoc/Shellwords.html#method-c-shellwords]. :include: shellwords.rb Executions: $ ruby shellwords.rb --shellwords "ruby my_prog.rb | less" [["ruby", "my_prog.rb", "|", "less"], Array] $ ruby shellwords.rb --shellwords "here are 'two words'" [["here", "are", "two words"], Array] ==== \Integer File +integer.rb+ defines an option whose argument is to be converted to an \Integer object. The argument is converted by method {Kernel.Integer}[https://ruby-doc.org/core/Kernel.html#method-i-Integer]. :include: integer.rb Executions: $ ruby integer.rb --integer 100 [100, Integer] $ ruby integer.rb --integer -100 [-100, Integer] $ ruby integer.rb --integer 0100 [64, Integer] $ ruby integer.rb --integer 0x100 [256, Integer] $ ruby integer.rb --integer 0b100 [4, Integer] ==== \Float File +float.rb+ defines an option whose argument is to be converted to a \Float object. The argument is converted by method {Kernel.Float}[https://ruby-doc.org/core/Kernel.html#method-i-Float]. :include: float.rb Executions: $ ruby float.rb --float 1 [1.0, Float] $ ruby float.rb --float 3.14159 [3.14159, Float] $ ruby float.rb --float 1.234E2 [123.4, Float] $ ruby float.rb --float 1.234E-2 [0.01234, Float] ==== \Numeric File +numeric.rb+ defines an option whose argument is to be converted to an instance of \Rational, \Float, or \Integer. The argument is converted by method {Kernel.Rational}[https://ruby-doc.org/core/Kernel.html#method-i-Rational], {Kernel.Float}[https://ruby-doc.org/core/Kernel.html#method-i-Float], or {Kernel.Integer}[https://ruby-doc.org/core/Kernel.html#method-i-Integer]. :include: numeric.rb Executions: $ ruby numeric.rb --numeric 1/3 [(1/3), Rational] $ ruby numeric.rb --numeric 3.333E-1 [0.3333, Float] $ ruby numeric.rb --numeric 3 [3, Integer] ==== \DecimalInteger File +decimal_integer.rb+ defines an option whose argument is to be converted to an \Integer object. The argument is converted by method {Kernel.Integer}[https://ruby-doc.org/core/Kernel.html#method-i-Integer]. :include: decimal_integer.rb The argument may not be in a binary or hexadecimal format; a leading zero is ignored (not parsed as octal). Executions: $ ruby decimal_integer.rb --decimal_integer 100 [100, Integer] $ ruby decimal_integer.rb --decimal_integer -100 [-100, Integer] $ ruby decimal_integer.rb --decimal_integer 0100 [100, Integer] $ ruby decimal_integer.rb --decimal_integer -0100 [-100, Integer] ==== \OctalInteger File +octal_integer.rb+ defines an option whose argument is to be converted to an \Integer object. The argument is converted by method {Kernel.Integer}[https://ruby-doc.org/core/Kernel.html#method-i-Integer]. :include: octal_integer.rb The argument may not be in a binary or hexadecimal format; it is parsed as octal, regardless of whether it has a leading zero. Executions: $ ruby octal_integer.rb --octal_integer 100 [64, Integer] $ ruby octal_integer.rb --octal_integer -100 [-64, Integer] $ ruby octal_integer.rb --octal_integer 0100 [64, Integer] ==== \DecimalNumeric File +decimal_numeric.rb+ defines an option whose argument is to be converted to an \Integer object. The argument is converted by method {Kernel.Integer}[https://ruby-doc.org/core/Kernel.html#method-i-Integer]. :include: decimal_numeric.rb The argument may not be in a binary or hexadecimal format; a leading zero causes the argument to be parsed as octal. Executions: $ ruby decimal_numeric.rb --decimal_numeric 100 [100, Integer] $ ruby decimal_numeric.rb --decimal_numeric -100 [-100, Integer] $ ruby decimal_numeric.rb --decimal_numeric 0100 [64, Integer] ==== \TrueClass File +true_class.rb+ defines an option whose argument is to be converted to +true+ or +false+. The argument is evaluated by method {Object#nil?}[https://ruby-doc.org/core-3.0.0/Object.html#method-i-nil-3F]. :include: true_class.rb The argument may be any of those shown in the examples below. Executions: $ ruby true_class.rb --true_class true [true, TrueClass] $ ruby true_class.rb --true_class yes [true, TrueClass] $ ruby true_class.rb --true_class + [true, TrueClass] $ ruby true_class.rb --true_class false [false, FalseClass] $ ruby true_class.rb --true_class no [false, FalseClass] $ ruby true_class.rb --true_class - [false, FalseClass] $ ruby true_class.rb --true_class nil [false, FalseClass] ==== \FalseClass File +false_class.rb+ defines an option whose argument is to be converted to +true+ or +false+. The argument is evaluated by method {Object#nil?}[https://ruby-doc.org/core-3.0.0/Object.html#method-i-nil-3F]. :include: false_class.rb The argument may be any of those shown in the examples below. Executions: $ ruby false_class.rb --false_class false [false, FalseClass] $ ruby false_class.rb --false_class no [false, FalseClass] $ ruby false_class.rb --false_class - [false, FalseClass] $ ruby false_class.rb --false_class nil [false, FalseClass] $ ruby false_class.rb --false_class true [true, TrueClass] $ ruby false_class.rb --false_class yes [true, TrueClass] $ ruby false_class.rb --false_class + [true, TrueClass] ==== \Object File +object.rb+ defines an option whose argument is not to be converted from \String. :include: object.rb Executions: $ ruby object.rb --object foo ["foo", String] $ ruby object.rb --object nil ["nil", String] ==== \String File +string.rb+ defines an option whose argument is not to be converted from \String. :include: string.rb Executions: $ ruby string.rb --string foo ["foo", String] $ ruby string.rb --string nil ["nil", String] ==== \Array File +array.rb+ defines an option whose argument is to be converted from \String to an array of strings, based on comma-separated substrings. :include: array.rb Executions: $ ruby array.rb --array "" [[], Array] $ ruby array.rb --array foo,bar,baz [["foo", "bar", "baz"], Array] $ ruby array.rb --array "foo, bar, baz" [["foo", " bar", " baz"], Array] ==== \Regexp File +regexp.rb+ defines an option whose argument is to be converted to a \Regexp object. :include: regexp.rb Executions: $ ruby regexp.rb --regexp foo === Descriptions A description parameter is any string parameter that is not recognized as an {option name}[#label-Option+Names] or a {terminator}[#label-Terminators]; in other words, it does not begin with a hypnen. You may give any number of description parameters; each becomes a line in the text generated by option --help. File +descriptions.rb+ has six strings in its array +descriptions+. These are all passed as parameters to OptionParser#on, so that they all, line for line, become the option's description. :include: descriptions.rb Executions: $ ruby descriptions.rb --help Usage: descriptions [options] --xxx Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget. Aenean massa. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Donec quam felis, ultricies nec, pellentesque eu, pretium quis, sem. $ ruby descriptions.rb --xxx ["--xxx", true] === Option Handlers The handler for an option is an executable that will be called when the option is encountered. The handler may be: - A block (this is most often seen). - A proc. - A method. ==== Handler Blocks An option hadler may be a block. File +block.rb+ defines an option that has a handler block. :include: block.rb Executions: $ ruby block.rb --help Usage: block [options] --xxx Option with no argument --yyy YYY Option with required argument $ ruby block.rb --xxx ["Handler block for -xxx called with value:", true] $ ruby block.rb --yyy FOO ["Handler block for -yyy called with value:", "FOO"] ==== Handler Procs An option handler may be a Proc. File +proc.rb+ defines an option that has a handler proc. :include: proc.rb Executions: $ ruby proc.rb --help Usage: proc [options] --xxx Option with no argument --yyy YYY Option with required argument $ ruby proc.rb --xxx ["Handler proc for -xxx called with value:", true] $ ruby proc.rb --yyy FOO ["Handler proc for -yyy called with value:", "FOO"] ==== Handler Methods An option handler may be a Method. File +proc.rb+ defines an option that has a handler method. :include: method.rb Executions: $ ruby method.rb --help Usage: method [options] --xxx Option with no argument --yyy YYY Option with required argument $ ruby method.rb --xxx ["Handler method for -xxx called with value:", true] $ ruby method.rb --yyy FOO ["Handler method for -yyy called with value:", "FOO"] === Terminators And finally, the terminator parameter -- tells the options parser to ignore any options farther to the right. This can be useful if there are options not meant for the current program. File +terminator.rb+ defines one option --my_option. :include: terminator.rb The first execution fails because --nosuch is not a defined option; the second succeeds because -- causes that option to be ignored: $ ruby terminator.rb --my_option FOO --other_option BAR ["FOO", String] terminator.rb:6:in `
': invalid option: --other_option (OptionParser::InvalidOption) $ ruby terminator.rb --my_option FOO -- --other_option BAR ["FOO", String]