Argument Converters¶ ↑
An option can specify that its argument is to be converted from the default String to an instance of another class.
Contents¶ ↑
Built-In Argument Converters¶ ↑
OptionParser has a number of built-in argument 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.
require 'optparse/date' parser = OptionParser.new parser.on('--date=DATE', Date) do |value| p [value, value.class] end parser.parse!
Executions:
$ ruby date.rb --date 2001-02-03 [#<Date: 2001-02-03 ((2451944j,0s,0n),+0s,2299161j)>, Date] $ ruby date.rb --date 20010203 [#<Date: 2001-02-03 ((2451944j,0s,0n),+0s,2299161j)>, Date] $ ruby date.rb --date "3rd Feb 2001" [#<Date: 2001-02-03 ((2451944j,0s,0n),+0s,2299161j)>, 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.
require 'optparse/date' parser = OptionParser.new parser.on('--datetime=DATETIME', DateTime) do |value| p [value, value.class] end parser.parse!
Executions:
$ ruby datetime.rb --datetime 2001-02-03T04:05:06+07:00 [#<DateTime: 2001-02-03T04:05:06+07:00 ((2451943j,75906s,0n),+25200s,2299161j)>, DateTime] $ ruby datetime.rb --datetime 20010203T040506+0700 [#<DateTime: 2001-02-03T04:05:06+07:00 ((2451943j,75906s,0n),+25200s,2299161j)>, DateTime] $ ruby datetime.rb --datetime "3rd Feb 2001 04:05:06 PM" [#<DateTime: 2001-02-03T16:05:06+00:00 ((2451944j,57906s,0n),+0s,2299161j)>, 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 or Time#parse.
require 'optparse/time' parser = OptionParser.new parser.on('--time=TIME', Time) do |value| p [value, value.class] end parser.parse!
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.
require 'optparse/uri' parser = OptionParser.new parser.on('--uri=URI', URI) do |value| p [value, value.class] end parser.parse!
Executions:
$ ruby uri.rb --uri https://github.com [#<URI::HTTPS https://github.com>, URI::HTTPS] $ ruby uri.rb --uri http://github.com [#<URI::HTTP http://github.com>, URI::HTTP] $ ruby uri.rb --uri file://~/var [#<URI::File 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.
require 'optparse/shellwords' parser = OptionParser.new parser.on('--shellwords=SHELLWORDS', Shellwords) do |value| p [value, value.class] end parser.parse!
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.
require 'optparse' parser = OptionParser.new parser.on('--integer=INTEGER', Integer) do |value| p [value, value.class] end parser.parse!
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.
require 'optparse' parser = OptionParser.new parser.on('--float=FLOAT', Float) do |value| p [value, value.class] end parser.parse!
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, Kernel#Float, or Kernel#Integer.
require 'optparse' parser = OptionParser.new parser.on('--numeric=NUMERIC', Numeric) do |value| p [value, value.class] end parser.parse!
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.
require 'optparse' include OptionParser::Acceptables parser = OptionParser.new parser.on('--decimal_integer=DECIMAL_INTEGER', DecimalInteger) do |value| p [value, value.class] end parser.parse!
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.
require 'optparse' include OptionParser::Acceptables parser = OptionParser.new parser.on('--octal_integer=OCTAL_INTEGER', OctalInteger) do |value| p [value, value.class] end parser.parse!
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
require 'optparse' include OptionParser::Acceptables parser = OptionParser.new parser.on('--decimal_numeric=DECIMAL_NUMERIC', DecimalNumeric) do |value| p [value, value.class] end parser.parse!
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?.
require 'optparse' parser = OptionParser.new parser.on('--true_class=TRUE_CLASS', TrueClass) do |value| p [value, value.class] end parser.parse!
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?.
require 'optparse' parser = OptionParser.new parser.on('--false_class=FALSE_CLASS', FalseClass) do |value| p [value, value.class] end parser.parse!
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.
require 'optparse' parser = OptionParser.new parser.on('--object=OBJECT', Object) do |value| p [value, value.class] end parser.parse!
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.
require 'optparse' parser = OptionParser.new parser.on('--string=STRING', String) do |value| p [value, value.class] end parser.parse!
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.
require 'optparse' parser = OptionParser.new parser.on('--array=ARRAY', Array) do |value| p [value, value.class] end parser.parse!
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.
require 'optparse' parser = OptionParser.new parser.on('--regexp=REGEXP', Regexp) do |value| p [value, value.class] end parser.parse!
Executions:
$ ruby regexp.rb --regexp foo
Custom Argument Converters¶ ↑
You can create custom argument converters. To create a custom converter, call OptionParser#accept with:
-
An identifier, which may be any object.
-
An optional match pattern, which defaults to
/.*/m. -
A block that accepts the argument and returns the converted value.
This custom converter accepts any argument and converts it, if possible, to a Complex object.
require 'optparse/date' parser = OptionParser.new parser.accept(Complex) do |value| value.to_c end parser.on('--complex COMPLEX', Complex) do |value| p [value, value.class] end parser.parse!
Executions:
$ ruby custom_converter.rb --complex 0 [(0+0i), Complex] $ ruby custom_converter.rb --complex 1 [(1+0i), Complex] $ ruby custom_converter.rb --complex 1+2i [(1+2i), Complex] $ ruby custom_converter.rb --complex 0.3-0.5i [(0.3-0.5i), Complex]
This custom converter accepts any 1-word argument and capitalizes it, if possible.
require 'optparse/date' parser = OptionParser.new parser.accept(:capitalize, /\w*/) do |value| value.capitalize end parser.on('--capitalize XXX', :capitalize) do |value| p [value, value.class] end parser.parse!
Executions:
$ ruby match_converter.rb --capitalize foo ["Foo", String] $ ruby match_converter.rb --capitalize "foo bar" match_converter.rb:9:in `<main>': invalid argument: --capitalize foo bar (OptionParser::InvalidArgument)