class Object

Object is the default root of all Ruby objects. Object inherits from BasicObject which allows creating alternate object hierarchies. Methods on Object are available to all classes unless explicitly overridden.

Object mixes in the Kernel module, making the built-in kernel functions globally accessible. Although the instance methods of Object are defined by the Kernel module, we have chosen to document them here for clarity.

When referencing constants in classes inheriting from Object you do not need to use the full namespace. For example, referencing File inside YourClass will find the top-level File class.

In the descriptions of Object's methods, the parameter symbol refers to a symbol, which is either a quoted string or a Symbol (such as :name).

Constants

ARGF

ARGF is a stream designed for use in scripts that process files given as command-line arguments or passed in via STDIN.

See ARGF (the class) for more details.

ARGV

ARGV contains the command line arguments used to run ruby.

A library like OptionParser can be used to process command-line arguments.

DATA

DATA is a File that contains the data section of the executed file. To create a data section use __END__:

$ cat t.rb
puts DATA.gets
__END__
hello world!

$ ruby t.rb
hello world!
ENV

ENV is a Hash-like accessor for environment variables.

See ENV (the class) for more details.

FALSE

An alias of false

NIL

An alias of nil

OptParse

OptionParser

Introduction

OptionParser is a class for command-line option analysis. It is much more advanced, yet also easier to use, than GetoptLong, and is a more Ruby-oriented solution.

Features

  1. The argument specification and the code to handle it are written in the same place.

  2. It can output an option summary; you don't need to maintain this string separately.

  3. Optional and mandatory arguments are specified very gracefully.

  4. Arguments can be automatically converted to a specified class.

  5. Arguments can be restricted to a certain set.

All of these features are demonstrated in the examples below. See make_switch for full documentation.

Minimal example

require 'optparse'

options = {}
OptionParser.new do |opts|
  opts.banner = "Usage: example.rb [options]"

  opts.on("-v", "--[no-]verbose", "Run verbosely") do |v|
    options[:verbose] = v
  end
end.parse!

p options
p ARGV

Generating Help

OptionParser can be used to automatically generate help for the commands you write:

require 'optparse'

Options = Struct.new(:name)

class Parser
  def self.parse(options)
    args = Options.new("world")

    opt_parser = OptionParser.new do |opts|
      opts.banner = "Usage: example.rb [options]"

      opts.on("-nNAME", "--name=NAME", "Name to say hello to") do |n|
        args.name = n
      end

      opts.on("-h", "--help", "Prints this help") do
        puts opts
        exit
      end
    end

    opt_parser.parse!(options)
    return args
  end
end
options = Parser.parse %w[--help]

#=>
   # Usage: example.rb [options]
   #     -n, --name=NAME                  Name to say hello to
   #     -h, --help                       Prints this help

Required Arguments

For options that require an argument, option specification strings may include an option name in all caps. If an option is used without the required argument, an exception will be raised.

require 'optparse'

options = {}
OptionParser.new do |parser|
  parser.on("-r", "--require LIBRARY",
            "Require the LIBRARY before executing your script") do |lib|
    puts "You required #{lib}!"
  end
end.parse!

Used:

bash-3.2$ ruby optparse-test.rb -r
optparse-test.rb:9:in `<main>': missing argument: -r (OptionParser::MissingArgument)
bash-3.2$ ruby optparse-test.rb -r my-library
You required my-library!

Type Coercion

OptionParser supports the ability to coerce command line arguments into objects for us.

OptionParser comes with a few ready-to-use kinds of type coercion. They are:

  • Date – Anything accepted by Date.parse

  • DateTime – Anything accepted by DateTime.parse

  • Time – Anything accepted by Time.httpdate or Time.parse

  • URI – Anything accepted by URI.parse

  • Shellwords – Anything accepted by Shellwords.shellwords

  • String – Any non-empty string

  • Integer – Any integer. Will convert octal. (e.g. 124, -3, 040)

  • Float – Any float. (e.g. 10, 3.14, -100E+13)

  • Numeric – Any integer, float, or rational (1, 3.4, 1/3)

  • DecimalInteger – Like Integer, but no octal format.

  • OctalInteger – Like Integer, but no decimal format.

  • DecimalNumeric – Decimal integer or float.

  • TrueClass – Accepts '+, yes, true, -, no, false' and defaults as true

  • FalseClass – Same as TrueClass, but defaults to false

  • Array – Strings separated by ',' (e.g. 1,2,3)

  • Regexp – Regular expressions. Also includes options.

We can also add our own coercions, which we will cover soon.

Using Built-in Conversions

As an example, the built-in Time conversion is used. The other built-in conversions behave in the same way. OptionParser will attempt to parse the argument as a Time. If it succeeds, that time will be passed to the handler block. Otherwise, an exception will be raised.

require 'optparse'
require 'optparse/time'
OptionParser.new do |parser|
  parser.on("-t", "--time [TIME]", Time, "Begin execution at given time") do |time|
    p time
  end
end.parse!

Used:

bash-3.2$ ruby optparse-test.rb  -t nonsense
... invalid argument: -t nonsense (OptionParser::InvalidArgument)
from ... time.rb:5:in `block in <top (required)>'
from optparse-test.rb:31:in `<main>'
bash-3.2$ ruby optparse-test.rb  -t 10-11-12
2010-11-12 00:00:00 -0500
bash-3.2$ ruby optparse-test.rb  -t 9:30
2014-08-13 09:30:00 -0400

Creating Custom Conversions

The accept method on OptionParser may be used to create converters. It specifies which conversion block to call whenever a class is specified. The example below uses it to fetch a User object before the on handler receives it.

require 'optparse'

User = Struct.new(:id, :name)

def find_user id
  not_found = ->{ raise "No User Found for id #{id}" }
  [ User.new(1, "Sam"),
    User.new(2, "Gandalf") ].find(not_found) do |u|
    u.id == id
  end
end

op = OptionParser.new
op.accept(User) do |user_id|
  find_user user_id.to_i
end

op.on("--user ID", User) do |user|
  puts user
end

op.parse!

output:

bash-3.2$ ruby optparse-test.rb --user 1
#<struct User id=1, name="Sam">
bash-3.2$ ruby optparse-test.rb --user 2
#<struct User id=2, name="Gandalf">
bash-3.2$ ruby optparse-test.rb --user 3
optparse-test.rb:15:in `block in find_user': No User Found for id 3 (RuntimeError)

Complete example

The following example is a complete Ruby program. You can run it and see the effect of specifying various options. This is probably the best way to learn the features of optparse.

require 'optparse'
require 'optparse/time'
require 'ostruct'
require 'pp'

class OptparseExample
  Version = '1.0.0'

  CODES = %w[iso-2022-jp shift_jis euc-jp utf8 binary]
  CODE_ALIASES = { "jis" => "iso-2022-jp", "sjis" => "shift_jis" }

  class ScriptOptions
    attr_accessor :library, :inplace, :encoding, :transfer_type,
                  :verbose, :extension, :delay, :time, :record_separator,
                  :list

    def initialize
      self.library = []
      self.inplace = false
      self.encoding = "utf8"
      self.transfer_type = :auto
      self.verbose = false
    end

    def define_options(parser)
      parser.banner = "Usage: example.rb [options]"
      parser.separator ""
      parser.separator "Specific options:"

      # add additional options
      perform_inplace_option(parser)
      delay_execution_option(parser)
      execute_at_time_option(parser)
      specify_record_separator_option(parser)
      list_example_option(parser)
      specify_encoding_option(parser)
      optional_option_argument_with_keyword_completion_option(parser)
      boolean_verbose_option(parser)

      parser.separator ""
      parser.separator "Common options:"
      # No argument, shows at tail.  This will print an options summary.
      # Try it and see!
      parser.on_tail("-h", "--help", "Show this message") do
        puts parser
        exit
      end
      # Another typical switch to print the version.
      parser.on_tail("--version", "Show version") do
        puts Version
        exit
      end
    end

    def perform_inplace_option(parser)
      # Specifies an optional option argument
      parser.on("-i", "--inplace [EXTENSION]",
                "Edit ARGV files in place",
                "(make backup if EXTENSION supplied)") do |ext|
        self.inplace = true
        self.extension = ext || ''
        self.extension.sub!(/\A\.?(?=.)/, ".")  # Ensure extension begins with dot.
      end
    end

    def delay_execution_option(parser)
      # Cast 'delay' argument to a Float.
      parser.on("--delay N", Float, "Delay N seconds before executing") do |n|
        self.delay = n
      end
    end

    def execute_at_time_option(parser)
      # Cast 'time' argument to a Time object.
      parser.on("-t", "--time [TIME]", Time, "Begin execution at given time") do |time|
        self.time = time
      end
    end

    def specify_record_separator_option(parser)
      # Cast to octal integer.
      parser.on("-F", "--irs [OCTAL]", OptionParser::OctalInteger,
                "Specify record separator (default \\0)") do |rs|
        self.record_separator = rs
      end
    end

    def list_example_option(parser)
      # List of arguments.
      parser.on("--list x,y,z", Array, "Example 'list' of arguments") do |list|
        self.list = list
      end
    end

    def specify_encoding_option(parser)
      # Keyword completion.  We are specifying a specific set of arguments (CODES
      # and CODE_ALIASES - notice the latter is a Hash), and the user may provide
      # the shortest unambiguous text.
      code_list = (CODE_ALIASES.keys + CODES).join(', ')
      parser.on("--code CODE", CODES, CODE_ALIASES, "Select encoding",
                "(#{code_list})") do |encoding|
        self.encoding = encoding
      end
    end

    def optional_option_argument_with_keyword_completion_option(parser)
      # Optional '--type' option argument with keyword completion.
      parser.on("--type [TYPE]", [:text, :binary, :auto],
                "Select transfer type (text, binary, auto)") do |t|
        self.transfer_type = t
      end
    end

    def boolean_verbose_option(parser)
      # Boolean switch.
      parser.on("-v", "--[no-]verbose", "Run verbosely") do |v|
        self.verbose = v
      end
    end
  end

  #
  # Return a structure describing the options.
  #
  def parse(args)
    # The options specified on the command line will be collected in
    # *options*.

    @options = ScriptOptions.new
    @args = OptionParser.new do |parser|
      @options.define_options(parser)
      parser.parse!(args)
    end
    @options
  end

  attr_reader :parser, :options
end  # class OptparseExample

example = OptparseExample.new
options = example.parse(ARGV)
pp options # example.options
pp ARGV

Shell Completion

For modern shells (e.g. bash, zsh, etc.), you can use shell completion for command line options.

Further documentation

The above examples should be enough to learn how to use this class. If you have any questions, file a ticket at bugs.ruby-lang.org.

ParseError

The copyright string for ruby

RUBY_DESCRIPTION

The full ruby version string, like ruby -v prints'

RUBY_ENGINE

The engine or interpreter this ruby uses.

RUBY_ENGINE_VERSION

The version of the engine or interpreter this ruby uses.

RUBY_PATCHLEVEL

The patchlevel for this ruby. If this is a development build of ruby the patchlevel will be -1

RUBY_PLATFORM

The platform for this ruby

RUBY_RELEASE_DATE

The date this ruby was released

RUBY_REVISION

The SVN revision for this ruby.

RUBY_VERSION

The running version of ruby

STDERR

Holds the original stderr

STDIN

Holds the original stdin

STDOUT

Holds the original stdout

Synchronizer

A class that provides two-phase lock with a counter. See Sync_m for details.

Synchronizer_m

A module that provides a two-phase lock with a counter.

TOPLEVEL_BINDING

The Binding of the top level scope

TRUE

An alias of true

ThWait

This class watches for termination of multiple threads. Basic functionality (wait until specified threads have terminated) can be accessed through the class method ThreadsWait.all_waits. Finer control can be gained using instance methods.

Example:

ThreadsWait.all_waits(thr1, thr2, ...) do |t|
  STDERR.puts "Thread #{t} has terminated."
end

th = ThreadsWait.new(thread1,...)
th.next_wait # next one to be done
TimeoutError

Raised by Timeout#timeout when the block times out.

Public Class Methods

yaml_tag(url) click to toggle source
# File ext/psych/lib/psych/core_ext.rb, line 2
def self.yaml_tag url
  Psych.add_tag(url, self)
end

Public Instance Methods

obj !~ other → true or false click to toggle source

Returns true if two objects do not match (using the =~ method), otherwise false.

static VALUE
rb_obj_not_match(VALUE obj1, VALUE obj2)
{
    VALUE result = rb_funcall(obj1, id_match, 1, obj2);
    return RTEST(result) ? Qfalse : Qtrue;
}
obj <=> other → 0 or nil click to toggle source

Returns 0 if obj and other are the same object or obj == other, otherwise nil.

The <=> is used by various methods to compare objects, for example Enumerable#sort, Enumerable#max etc.

Your implementation of <=> should return one of the following values: -1, 0, 1 or nil. -1 means self is smaller than other. 0 means self is equal to other. 1 means self is bigger than other. Nil means the two values could not be compared.

When you define <=>, you can include Comparable to gain the methods <=, <, ==, >=, > and between?.

static VALUE
rb_obj_cmp(VALUE obj1, VALUE obj2)
{
    if (obj1 == obj2 || rb_equal(obj1, obj2))
        return INT2FIX(0);
    return Qnil;
}
obj === other → true or false click to toggle source

Case Equality – For class Object, effectively the same as calling #==, but typically overridden by descendants to provide meaningful semantics in case statements.

VALUE
rb_equal(VALUE obj1, VALUE obj2)
{
    VALUE result;

    if (obj1 == obj2) return Qtrue;
    result = rb_funcall(obj1, id_eq, 1, obj2);
    if (RTEST(result)) return Qtrue;
    return Qfalse;
}
obj =~ other → nil click to toggle source

Pattern Match—Overridden by descendants (notably Regexp and String) to provide meaningful pattern-match semantics.

static VALUE
rb_obj_match(VALUE obj1, VALUE obj2)
{
    return Qnil;
}
CSV(*args, &block) click to toggle source

Passes args to CSV.instance.

CSV("CSV,data").read
  #=> [["CSV", "data"]]

If a block is given, the instance is passed the block and the return value becomes the return value of the block.

CSV("CSV,data") { |c|
  c.read.any? { |a| a.include?("data") }
} #=> true

CSV("CSV,data") { |c|
  c.read.any? { |a| a.include?("zombies") }
} #=> false
# File lib/csv.rb, line 2326
def CSV(*args, &block)
  CSV.instance(*args, &block)
end
DelegateClass(superclass) click to toggle source

The primary interface to this library. Use to setup delegation when defining your class.

class MyClass < DelegateClass(ClassToDelegateTo) # Step 1
  def initialize
    super(obj_of_ClassToDelegateTo)              # Step 2
  end
end

Here's a sample of use from Tempfile which is really a File object with a few special rules about storage location and when the File should be deleted. That makes for an almost textbook perfect example of how to use delegation.

class Tempfile < DelegateClass(File)
  # constant and class member data initialization...

  def initialize(basename, tmpdir=Dir::tmpdir)
    # build up file path/name in var tmpname...

    @tmpfile = File.open(tmpname, File::RDWR|File::CREAT|File::EXCL, 0600)

    # ...

    super(@tmpfile)

    # below this point, all methods of File are supported...
  end

  # ...
end
Calls superclass method
# File lib/delegate.rb, line 377
def DelegateClass(superclass)
  klass = Class.new(Delegator)
  methods = superclass.instance_methods
  methods -= ::Delegator.public_api
  methods -= [:to_s,:inspect,:=~,:!~,:===]
  klass.module_eval do
    def __getobj__  # :nodoc:
      unless defined?(@delegate_dc_obj)
        return yield if block_given?
        __raise__ ::ArgumentError, "not delegated"
      end
      @delegate_dc_obj
    end
    def __setobj__(obj)  # :nodoc:
      __raise__ ::ArgumentError, "cannot delegate to self" if self.equal?(obj)
      @delegate_dc_obj = obj
    end
    methods.each do |method|
      define_method(method, Delegator.delegating_block(method))
    end
  end
  klass.define_singleton_method :public_instance_methods do |all=true|
    super(all) - superclass.protected_instance_methods
  end
  klass.define_singleton_method :protected_instance_methods do |all=true|
    super(all) | superclass.protected_instance_methods
  end
  return klass
end
Digest(name) → digest_subclass click to toggle source

Returns a Digest subclass by name in a thread-safe manner even when on-demand loading is involved.

require 'digest'

Digest("MD5")
# => Digest::MD5

Digest(:SHA256)
# => Digest::SHA256

Digest(:Foo)
# => LoadError: library not found for class Digest::Foo -- digest/foo
# File ext/digest/lib/digest.rb, line 95
def Digest(name)
  const = name.to_sym
  Digest::REQUIRE_MUTEX.synchronize {
    # Ignore autoload's because it is void when we have #const_missing
    Digest.const_missing(const)
  }
rescue LoadError
  # Constants do not necessarily rely on digest/*.
  if Digest.const_defined?(const)
    Digest.const_get(const)
  else
    raise
  end
end
class → class click to toggle source

Returns the class of obj. This method must always be called with an explicit receiver, as class is also a reserved word in Ruby.

1.class      #=> Fixnum
self.class   #=> Object
VALUE
rb_obj_class(VALUE obj)
{
    return rb_class_real(CLASS_OF(obj));
}
clone → an_object click to toggle source

Produces a shallow copy of obj—the instance variables of obj are copied, but not the objects they reference. clone copies the frozen and tainted state of obj. See also the discussion under Object#dup.

class Klass
   attr_accessor :str
end
s1 = Klass.new      #=> #<Klass:0x401b3a38>
s1.str = "Hello"    #=> "Hello"
s2 = s1.clone       #=> #<Klass:0x401b3998 @str="Hello">
s2.str[1,4] = "i"   #=> "i"
s1.inspect          #=> "#<Klass:0x401b3a38 @str=\"Hi\">"
s2.inspect          #=> "#<Klass:0x401b3998 @str=\"Hi\">"

This method may have class-specific behavior. If so, that behavior will be documented under the #initialize_copy method of the class.

VALUE
rb_obj_clone(VALUE obj)
{
    VALUE clone;
    VALUE singleton;

    if (rb_special_const_p(obj)) {
        rb_raise(rb_eTypeError, "can't clone %s", rb_obj_classname(obj));
    }
    clone = rb_obj_alloc(rb_obj_class(obj));
    RBASIC(clone)->flags &= (FL_TAINT|FL_PROMOTED0|FL_PROMOTED1);
    RBASIC(clone)->flags |= RBASIC(obj)->flags & ~(FL_PROMOTED0|FL_PROMOTED1|FL_FREEZE|FL_FINALIZE);

    singleton = rb_singleton_class_clone_and_attach(obj, clone);
    RBASIC_SET_CLASS(clone, singleton);
    if (FL_TEST(singleton, FL_SINGLETON)) {
        rb_singleton_class_attached(singleton, clone);
    }

    init_copy(clone, obj);
    rb_funcall(clone, id_init_clone, 1, obj);
    RBASIC(clone)->flags |= RBASIC(obj)->flags & FL_FREEZE;

    return clone;
}
dclone() click to toggle source

provides a unified clone operation, for REXML::XPathParser to use across multiple Object types

# File lib/rexml/xpath_parser.rb, line 10
def dclone
  clone
end
default_src_encoding() click to toggle source

DO NOT WRITE ANY MAGIC COMMENT HERE.

# File lib/irb/src_encoding.rb, line 2
def default_src_encoding
  return __ENCODING__
end
define_singleton_method(symbol, method) → new_method click to toggle source
define_singleton_method(symbol) { block } → proc

Defines a singleton method in the receiver. The method parameter can be a Proc, a Method or an UnboundMethod object. If a block is specified, it is used as the method body.

class A
  class << self
    def class_name
      to_s
    end
  end
end
A.define_singleton_method(:who_am_i) do
  "I am: #{class_name}"
end
A.who_am_i   # ==> "I am: A"

guy = "Bob"
guy.define_singleton_method(:hello) { "#{self}: Hello there!" }
guy.hello    #=>  "Bob: Hello there!"
static VALUE
rb_obj_define_method(int argc, VALUE *argv, VALUE obj)
{
    VALUE klass = rb_singleton_class(obj);

    return rb_mod_define_method(argc, argv, klass);
}
display(port=$>) → nil click to toggle source

Prints obj on the given port (default $>). Equivalent to:

def display(port=$>)
  port.write self
end

For example:

1.display
"cat".display
[ 4, 5, 6 ].display
puts

produces:

1cat456
static VALUE
rb_obj_display(int argc, VALUE *argv, VALUE self)
{
    VALUE out;

    if (argc == 0) {
        out = rb_stdout;
    }
    else {
        rb_scan_args(argc, argv, "01", &out);
    }
    rb_io_write(out, self);

    return Qnil;
}
dup → an_object click to toggle source

Produces a shallow copy of obj—the instance variables of obj are copied, but not the objects they reference. dup copies the tainted state of obj.

This method may have class-specific behavior. If so, that behavior will be documented under the #initialize_copy method of the class.

on dup vs clone

In general, clone and dup may have different semantics in descendant classes. While clone is used to duplicate an object, including its internal state, dup typically uses the class of the descendant object to create the new instance.

When using dup, any modules that the object has been extended with will not be copied.

class Klass
  attr_accessor :str
end

module Foo
  def foo; 'foo'; end
end

s1 = Klass.new #=> #<Klass:0x401b3a38>
s1.extend(Foo) #=> #<Klass:0x401b3a38>
s1.foo #=> "foo"

s2 = s1.clone #=> #<Klass:0x401b3a38>
s2.foo #=> "foo"

s3 = s1.dup #=> #<Klass:0x401b3a38>
s3.foo #=> NoMethodError: undefined method `foo' for #<Klass:0x401b3a38>
VALUE
rb_obj_dup(VALUE obj)
{
    VALUE dup;

    if (rb_special_const_p(obj)) {
        rb_raise(rb_eTypeError, "can't dup %s", rb_obj_classname(obj));
    }
    dup = rb_obj_alloc(rb_obj_class(obj));
    init_copy(dup, obj);
    rb_funcall(dup, id_init_dup, 1, obj);

    return dup;
}
enum_for(method = :each, *args) → enum click to toggle source
enum_for(method = :each, *args){|*args| block} → enum

Creates a new Enumerator which will enumerate by calling method on obj, passing args if any.

If a block is given, it will be used to calculate the size of the enumerator without the need to iterate it (see Enumerator#size).

Examples

str = "xyz"

enum = str.enum_for(:each_byte)
enum.each { |b| puts b }
# => 120
# => 121
# => 122

# protect an array from being modified by some_method
a = [1, 2, 3]
some_method(a.to_enum)

It is typical to call #to_enum when defining methods for a generic Enumerable, in case no block is passed.

Here is such an example, with parameter passing and a sizing block:

module Enumerable
  # a generic method to repeat the values of any enumerable
  def repeat(n)
    raise ArgumentError, "#{n} is negative!" if n < 0
    unless block_given?
      return to_enum(__method__, n) do # __method__ is :repeat here
        sz = size     # Call size and multiply by n...
        sz * n if sz  # but return nil if size itself is nil
      end
    end
    each do |*val|
      n.times { yield *val }
    end
  end
end

%[hello world].repeat(2) { |w| puts w }
  # => Prints 'hello', 'hello', 'world', 'world'
enum = (1..14).repeat(3)
  # => returns an Enumerator when called without a block
enum.first(4) # => [1, 1, 1, 2]
enum.size # => 42
static VALUE
obj_to_enum(int argc, VALUE *argv, VALUE obj)
{
    VALUE enumerator, meth = sym_each;

    if (argc > 0) {
        --argc;
        meth = *argv++;
    }
    enumerator = rb_enumeratorize_with_size(obj, meth, argc, argv, 0);
    if (rb_block_given_p()) {
        enumerator_ptr(enumerator)->size = rb_block_proc();
    }
    return enumerator;
}
obj == other → true or false click to toggle source
equal?(other) → true or false
eql?(other) → true or false

Equality — At the Object level, == returns true only if obj and other are the same object. Typically, this method is overridden in descendant classes to provide class-specific meaning.

Unlike ==, the equal? method should never be overridden by subclasses as it is used to determine object identity (that is, a.equal?(b) if and only if a is the same object as b):

obj = "a"
other = obj.dup

obj == other      #=> true
obj.equal? other  #=> false
obj.equal? obj    #=> true

The eql? method returns true if obj and other refer to the same hash key. This is used by Hash to test members for equality. For objects of class Object, eql? is synonymous with ==. Subclasses normally continue this tradition by aliasing eql? to their overridden == method, but there are exceptions. Numeric types, for example, perform type conversion across ==, but not across eql?, so:

1 == 1.0     #=> true
1.eql? 1.0   #=> false
VALUE
rb_obj_equal(VALUE obj1, VALUE obj2)
{
    if (obj1 == obj2) return Qtrue;
    return Qfalse;
}
extend(module, ...) → obj click to toggle source

Adds to obj the instance methods from each module given as a parameter.

module Mod
  def hello
    "Hello from Mod.\n"
  end
end

class Klass
  def hello
    "Hello from Klass.\n"
  end
end

k = Klass.new
k.hello         #=> "Hello from Klass.\n"
k.extend(Mod)   #=> #<Klass:0x401b3bc8>
k.hello         #=> "Hello from Mod.\n"
static VALUE
rb_obj_extend(int argc, VALUE *argv, VALUE obj)
{
    int i;
    ID id_extend_object, id_extended;

    CONST_ID(id_extend_object, "extend_object");
    CONST_ID(id_extended, "extended");

    rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS);
    for (i = 0; i < argc; i++)
        Check_Type(argv[i], T_MODULE);
    while (argc--) {
        rb_funcall(argv[argc], id_extend_object, 1, obj);
        rb_funcall(argv[argc], id_extended, 1, obj);
    }
    return obj;
}
freeze → obj click to toggle source

Prevents further modifications to obj. A RuntimeError will be raised if modification is attempted. There is no way to unfreeze a frozen object. See also Object#frozen?.

This method returns self.

a = [ "a", "b", "c" ]
a.freeze
a << "z"

produces:

prog.rb:3:in `<<': can't modify frozen Array (RuntimeError)
 from prog.rb:3

Objects of the following classes are always frozen: Fixnum, Bignum, Float, Symbol.

VALUE
rb_obj_freeze(VALUE obj)
{
    if (!OBJ_FROZEN(obj)) {
        OBJ_FREEZE(obj);
        if (SPECIAL_CONST_P(obj)) {
            rb_bug("special consts should be frozen.");
        }
    }
    return obj;
}
frozen? → true or false click to toggle source

Returns the freeze status of obj.

a = [ "a", "b", "c" ]
a.freeze    #=> ["a", "b", "c"]
a.frozen?   #=> true
VALUE
rb_obj_frozen_p(VALUE obj)
{
    return OBJ_FROZEN(obj) ? Qtrue : Qfalse;
}
hash → fixnum click to toggle source

Generates a Fixnum hash value for this object. This function must have the property that a.eql?(b) implies a.hash == b.hash.

The hash value is used along with eql? by the Hash class to determine if two objects reference the same hash key. Any hash value that exceeds the capacity of a Fixnum will be truncated before being used.

The hash value for an object may not be identical across invocations or implementations of Ruby. If you need a stable identifier across Ruby invocations and implementations you will need to generate one with a custom method.

VALUE
rb_obj_hash(VALUE obj)
{
    VALUE oid = rb_obj_id(obj);
#if SIZEOF_LONG == SIZEOF_VOIDP
    st_index_t index = NUM2LONG(oid);
#elif SIZEOF_LONG_LONG == SIZEOF_VOIDP
    st_index_t index = NUM2LL(oid);
#else
# error not supported
#endif
    return LONG2FIX(rb_objid_hash(index));
}
inspect → string click to toggle source

Returns a string containing a human-readable representation of obj. The default inspect shows the object's class name, an encoding of the object id, and a list of the instance variables and their values (by calling inspect on each of them). User defined classes should override this method to provide a better representation of obj. When overriding this method, it should return a string whose encoding is compatible with the default external encoding.

[ 1, 2, 3..4, 'five' ].inspect   #=> "[1, 2, 3..4, \"five\"]"
Time.new.inspect                 #=> "2008-03-08 19:43:39 +0900"

class Foo
end
Foo.new.inspect                  #=> "#<Foo:0x0300c868>"

class Bar
  def initialize
    @bar = 1
  end
end
Bar.new.inspect                  #=> "#<Bar:0x0300c868 @bar=1>"
static VALUE
rb_obj_inspect(VALUE obj)
{
    if (rb_ivar_count(obj) > 0) {
        VALUE str;
        VALUE c = rb_class_name(CLASS_OF(obj));

        str = rb_sprintf("-<%"PRIsVALUE":%p", c, (void*)obj);
        return rb_exec_recursive(inspect_obj, obj, str);
    }
    else {
        return rb_any_to_s(obj);
    }
}
instance_of?(class) → true or false click to toggle source

Returns true if obj is an instance of the given class. See also Object#kind_of?.

class A;     end
class B < A; end
class C < B; end

b = B.new
b.instance_of? A   #=> false
b.instance_of? B   #=> true
b.instance_of? C   #=> false
VALUE
rb_obj_is_instance_of(VALUE obj, VALUE c)
{
    c = class_or_module_required(c);
    if (rb_obj_class(obj) == c) return Qtrue;
    return Qfalse;
}
instance_variable_defined?(symbol) → true or false click to toggle source
instance_variable_defined?(string) → true or false

Returns true if the given instance variable is defined in obj. String arguments are converted to symbols.

class Fred
  def initialize(p1, p2)
    @a, @b = p1, p2
  end
end
fred = Fred.new('cat', 99)
fred.instance_variable_defined?(:@a)    #=> true
fred.instance_variable_defined?("@b")   #=> true
fred.instance_variable_defined?("@c")   #=> false
static VALUE
rb_obj_ivar_defined(VALUE obj, VALUE iv)
{
    ID id = id_for_var(obj, iv, an, instance);

    if (!id) {
        return Qfalse;
    }
    return rb_ivar_defined(obj, id);
}
instance_variable_get(symbol) → obj click to toggle source
instance_variable_get(string) → obj

Returns the value of the given instance variable, or nil if the instance variable is not set. The @ part of the variable name should be included for regular instance variables. Throws a NameError exception if the supplied symbol is not valid as an instance variable name. String arguments are converted to symbols.

class Fred
  def initialize(p1, p2)
    @a, @b = p1, p2
  end
end
fred = Fred.new('cat', 99)
fred.instance_variable_get(:@a)    #=> "cat"
fred.instance_variable_get("@b")   #=> 99
static VALUE
rb_obj_ivar_get(VALUE obj, VALUE iv)
{
    ID id = id_for_var(obj, iv, an, instance);

    if (!id) {
        return Qnil;
    }
    return rb_ivar_get(obj, id);
}
instance_variable_set(symbol, obj) → obj click to toggle source
instance_variable_set(string, obj) → obj

Sets the instance variable named by symbol to the given object, thereby frustrating the efforts of the class's author to attempt to provide proper encapsulation. The variable does not have to exist prior to this call. If the instance variable name is passed as a string, that string is converted to a symbol.

class Fred
  def initialize(p1, p2)
    @a, @b = p1, p2
  end
end
fred = Fred.new('cat', 99)
fred.instance_variable_set(:@a, 'dog')   #=> "dog"
fred.instance_variable_set(:@c, 'cat')   #=> "cat"
fred.inspect                             #=> "#<Fred:0x401b3da8 @a=\"dog\", @b=99, @c=\"cat\">"
static VALUE
rb_obj_ivar_set(VALUE obj, VALUE iv, VALUE val)
{
    ID id = id_for_var(obj, iv, an, instance);
    if (!id) id = rb_intern_str(iv);
    return rb_ivar_set(obj, id, val);
}
instance_variables → array click to toggle source

Returns an array of instance variable names for the receiver. Note that simply defining an accessor does not create the corresponding instance variable.

class Fred
  attr_accessor :a1
  def initialize
    @iv = 3
  end
end
Fred.new.instance_variables   #=> [:@iv]
VALUE
rb_obj_instance_variables(VALUE obj)
{
    VALUE ary;

    ary = rb_ary_new();
    rb_ivar_foreach(obj, ivar_i, ary);
    return ary;
}
is_a?(class) → true or false click to toggle source

Returns true if class is the class of obj, or if class is one of the superclasses of obj or modules included in obj.

module M;    end
class A
  include M
end
class B < A; end
class C < B; end

b = B.new
b.is_a? A          #=> true
b.is_a? B          #=> true
b.is_a? C          #=> false
b.is_a? M          #=> true

b.kind_of? A       #=> true
b.kind_of? B       #=> true
b.kind_of? C       #=> false
b.kind_of? M       #=> true
VALUE
rb_obj_is_kind_of(VALUE obj, VALUE c)
{
    VALUE cl = CLASS_OF(obj);

    c = class_or_module_required(c);
    return class_search_ancestor(cl, RCLASS_ORIGIN(c)) ? Qtrue : Qfalse;
}
itself → an_object click to toggle source

Returns obj.

string = 'my string' #=> "my string"
string.itself.object_id == string.object_id #=> true
static VALUE
rb_obj_itself(VALUE obj)
{
    return obj;
}
kind_of?(class) → true or false click to toggle source

Returns true if class is the class of obj, or if class is one of the superclasses of obj or modules included in obj.

module M;    end
class A
  include M
end
class B < A; end
class C < B; end

b = B.new
b.is_a? A          #=> true
b.is_a? B          #=> true
b.is_a? C          #=> false
b.is_a? M          #=> true

b.kind_of? A       #=> true
b.kind_of? B       #=> true
b.kind_of? C       #=> false
b.kind_of? M       #=> true
VALUE
rb_obj_is_kind_of(VALUE obj, VALUE c)
{
    VALUE cl = CLASS_OF(obj);

    c = class_or_module_required(c);
    return class_search_ancestor(cl, RCLASS_ORIGIN(c)) ? Qtrue : Qfalse;
}
method(sym) → method click to toggle source

Looks up the named method as a receiver in obj, returning a Method object (or raising NameError). The Method object acts as a closure in obj's object instance, so instance variables and the value of self remain available.

class Demo
  def initialize(n)
    @iv = n
  end
  def hello()
    "Hello, @iv = #{@iv}"
  end
end

k = Demo.new(99)
m = k.method(:hello)
m.call   #=> "Hello, @iv = 99"

l = Demo.new('Fred')
m = l.method("hello")
m.call   #=> "Hello, @iv = Fred"
VALUE
rb_obj_method(VALUE obj, VALUE vid)
{
    return obj_method(obj, vid, FALSE);
}
methods(regular=true) → array click to toggle source

Returns a list of the names of public and protected methods of obj. This will include all the methods accessible in obj's ancestors. If the optional parameter is false, it returns an array of obj<i>'s public and protected singleton methods, the array will not include methods in modules included in <i>obj.

class Klass
  def klass_method()
  end
end
k = Klass.new
k.methods[0..9]    #=> [:klass_method, :nil?, :===,
                   #    :==~, :!, :eql?
                   #    :hash, :<=>, :class, :singleton_class]
k.methods.length   #=> 56

k.methods(false)   #=> []
def k.singleton_method; end
k.methods(false)   #=> [:singleton_method]

module M123; def m123; end end
k.extend M123
k.methods(false)   #=> [:singleton_method]
VALUE
rb_obj_methods(int argc, const VALUE *argv, VALUE obj)
{
    rb_check_arity(argc, 0, 1);
    if (argc > 0 && !RTEST(argv[0])) {
	return rb_obj_singleton_methods(argc, argv, obj);
    }
    return class_instance_method_list(argc, argv, CLASS_OF(obj), 1, ins_methods_i);
}
nil? → true or false click to toggle source

Only the object nil responds true to nil?.

Object.new.nil?   #=> false
nil.nil?          #=> true
static VALUE
rb_false(VALUE obj)
{
    return Qfalse;
}
__id__ → integer click to toggle source
object_id → integer

Returns an integer identifier for obj.

The same number will be returned on all calls to object_id for a given object, and no two active objects will share an id.

Note: that some objects of builtin classes are reused for optimization. This is the case for immediate values and frozen string literals.

Immediate values are not passed by reference but are passed by value: nil, true, false, Fixnums, Symbols, and some Floats.

Object.new.object_id  == Object.new.object_id  # => false
(21 * 2).object_id    == (21 * 2).object_id    # => true
"hello".object_id     == "hello".object_id     # => false
"hi".freeze.object_id == "hi".freeze.object_id # => true
VALUE
rb_obj_id(VALUE obj)
{
    /*
     *                32-bit VALUE space
     *          MSB ------------------------ LSB
     *  false   00000000000000000000000000000000
     *  true    00000000000000000000000000000010
     *  nil     00000000000000000000000000000100
     *  undef   00000000000000000000000000000110
     *  symbol  ssssssssssssssssssssssss00001110
     *  object  oooooooooooooooooooooooooooooo00        = 0 (mod sizeof(RVALUE))
     *  fixnum  fffffffffffffffffffffffffffffff1
     *
     *                    object_id space
     *                                       LSB
     *  false   00000000000000000000000000000000
     *  true    00000000000000000000000000000010
     *  nil     00000000000000000000000000000100
     *  undef   00000000000000000000000000000110
     *  symbol   000SSSSSSSSSSSSSSSSSSSSSSSSSSS0        S...S % A = 4 (S...S = s...s * A + 4)
     *  object   oooooooooooooooooooooooooooooo0        o...o % A = 0
     *  fixnum  fffffffffffffffffffffffffffffff1        bignum if required
     *
     *  where A = sizeof(RVALUE)/4
     *
     *  sizeof(RVALUE) is
     *  20 if 32-bit, double is 4-byte aligned
     *  24 if 32-bit, double is 8-byte aligned
     *  40 if 64-bit
     */
    if (STATIC_SYM_P(obj)) {
        return (SYM2ID(obj) * sizeof(RVALUE) + (4 << 2)) | FIXNUM_FLAG;
    }
    else if (FLONUM_P(obj)) {
#if SIZEOF_LONG == SIZEOF_VOIDP
        return LONG2NUM((SIGNED_VALUE)obj);
#else
        return LL2NUM((SIGNED_VALUE)obj);
#endif
    }
    else if (SPECIAL_CONST_P(obj)) {
        return LONG2NUM((SIGNED_VALUE)obj);
    }
    return nonspecial_obj_id(obj);
}
private_methods(all=true) → array click to toggle source

Returns the list of private methods accessible to obj. If the all parameter is set to false, only those methods in the receiver will be listed.

VALUE
rb_obj_private_methods(int argc, const VALUE *argv, VALUE obj)
{
    return class_instance_method_list(argc, argv, CLASS_OF(obj), 1, ins_methods_priv_i);
}
protected_methods(all=true) → array click to toggle source

Returns the list of protected methods accessible to obj. If the all parameter is set to false, only those methods in the receiver will be listed.

VALUE
rb_obj_protected_methods(int argc, const VALUE *argv, VALUE obj)
{
    return class_instance_method_list(argc, argv, CLASS_OF(obj), 1, ins_methods_prot_i);
}
to_yaml(options = {}) click to toggle source

Convert an object to YAML. See Psych.dump for more information on the available options.

# File ext/psych/lib/psych/core_ext.rb, line 13
def psych_to_yaml options = {}
  Psych.dump self, options
end
Also aliased as: to_yaml
public_method(sym) → method click to toggle source

Similar to method, searches public method only.

VALUE
rb_obj_public_method(VALUE obj, VALUE vid)
{
    return obj_method(obj, vid, TRUE);
}
public_methods(all=true) → array click to toggle source

Returns the list of public methods accessible to obj. If the all parameter is set to false, only those methods in the receiver will be listed.

VALUE
rb_obj_public_methods(int argc, const VALUE *argv, VALUE obj)
{
    return class_instance_method_list(argc, argv, CLASS_OF(obj), 1, ins_methods_pub_i);
}
public_send(symbol [, args...]) → obj click to toggle source
public_send(string [, args...]) → obj

Invokes the method identified by symbol, passing it any arguments specified. Unlike send, #public_send calls public methods only. When the method is identified by a string, the string is converted to a symbol.

1.public_send(:puts, "hello")  # causes NoMethodError
VALUE
rb_f_public_send(int argc, VALUE *argv, VALUE recv)
{
    return send_internal(argc, argv, recv, CALL_PUBLIC);
}
remove_instance_variable(symbol) → obj click to toggle source

Removes the named instance variable from obj, returning that variable's value.

class Dummy
  attr_reader :var
  def initialize
    @var = 99
  end
  def remove
    remove_instance_variable(:@var)
  end
end
d = Dummy.new
d.var      #=> 99
d.remove   #=> 99
d.var      #=> nil
VALUE
rb_obj_remove_instance_variable(VALUE obj, VALUE name)
{
    VALUE val = Qnil;
    const ID id = id_for_var(obj, name, an, instance);
    st_data_t n, v;
    struct st_table *iv_index_tbl;
    st_data_t index;

    rb_check_frozen(obj);
    if (!id) {
	goto not_defined;
    }

    switch (BUILTIN_TYPE(obj)) {
      case T_OBJECT:
        iv_index_tbl = ROBJECT_IV_INDEX_TBL(obj);
        if (!iv_index_tbl) break;
        if (!st_lookup(iv_index_tbl, (st_data_t)id, &index)) break;
        if (ROBJECT_NUMIV(obj) <= (long)index) break;
        val = ROBJECT_IVPTR(obj)[index];
        if (val != Qundef) {
            ROBJECT_IVPTR(obj)[index] = Qundef;
            return val;
        }
	break;
      case T_CLASS:
      case T_MODULE:
	n = id;
	if (RCLASS_IV_TBL(obj) && st_delete(RCLASS_IV_TBL(obj), &n, &v)) {
	    return (VALUE)v;
	}
	break;
      default:
	if (FL_TEST(obj, FL_EXIVAR)) {
	    if (generic_ivar_remove(obj, id, &val)) {
		return val;
	    }
	}
	break;
    }

  not_defined:
    rb_name_err_raise("instance variable %1$s not defined",
		      obj, name);
    UNREACHABLE;
}
respond_to?(symbol, include_all=false) → true or false click to toggle source
respond_to?(string, include_all=false) → true or false

Returns true if obj responds to the given method. Private and protected methods are included in the search only if the optional second parameter evaluates to true.

If the method is not implemented, as Process.fork on Windows, File.lchmod on GNU/Linux, etc., false is returned.

If the method is not defined, respond_to_missing? method is called and the result is returned.

When the method name parameter is given as a string, the string is converted to a symbol.

static VALUE
obj_respond_to(int argc, VALUE *argv, VALUE obj)
{
    VALUE mid, priv;
    ID id;
    rb_thread_t *th = GET_THREAD();

    rb_scan_args(argc, argv, "11", &mid, &priv);
    if (!(id = rb_check_id(&mid))) {
        VALUE ret = basic_obj_respond_to_missing(th, CLASS_OF(obj), obj,
                                                 rb_to_symbol(mid), priv);
        if (ret == Qundef) ret = Qfalse;
        return ret;
    }
    if (basic_obj_respond_to(th, obj, id, !RTEST(priv)))
        return Qtrue;
    return Qfalse;
}
respond_to_missing?(symbol, include_all) → true or false click to toggle source
respond_to_missing?(string, include_all) → true or false

DO NOT USE THIS DIRECTLY.

Hook method to return whether the obj can respond to id method or not.

When the method name parameter is given as a string, the string is converted to a symbol.

See respond_to?, and the example of BasicObject.

static VALUE
obj_respond_to_missing(VALUE obj, VALUE mid, VALUE priv)
{
    return Qfalse;
}
send(symbol [, args...]) → obj click to toggle source
__send__(symbol [, args...]) → obj
send(string [, args...]) → obj
__send__(string [, args...]) → obj

Invokes the method identified by symbol, passing it any arguments specified. You can use __send__ if the name send clashes with an existing method in obj. When the method is identified by a string, the string is converted to a symbol.

class Klass
  def hello(*args)
    "Hello " + args.join(' ')
  end
end
k = Klass.new
k.send :hello, "gentle", "readers"   #=> "Hello gentle readers"
VALUE
rb_f_send(int argc, VALUE *argv, VALUE recv)
{
    return send_internal(argc, argv, recv, CALL_FCALL);
}
singleton_class → class click to toggle source

Returns the singleton class of obj. This method creates a new singleton class if obj does not have one.

If obj is nil, true, or false, it returns NilClass, TrueClass, or FalseClass, respectively. If obj is a Fixnum or a Symbol, it raises a TypeError.

Object.new.singleton_class  #=> #<Class:#<Object:0xb7ce1e24>>
String.singleton_class      #=> #<Class:String>
nil.singleton_class         #=> NilClass
static VALUE
rb_obj_singleton_class(VALUE obj)
{
    return rb_singleton_class(obj);
}
singleton_method(sym) → method click to toggle source

Similar to method, searches singleton method only.

class Demo
  def initialize(n)
    @iv = n
  end
  def hello()
    "Hello, @iv = #{@iv}"
  end
end

k = Demo.new(99)
def k.hi
  "Hi, @iv = #{@iv}"
end
m = k.singleton_method(:hi)
m.call   #=> "Hi, @iv = 99"
m = k.singleton_method(:hello) #=> NameError
VALUE
rb_obj_singleton_method(VALUE obj, VALUE vid)
{
    const rb_method_entry_t *me;
    VALUE klass;
    ID id = rb_check_id(&vid);

    if (!id) {
        if (!NIL_P(klass = rb_singleton_class_get(obj)) &&
            respond_to_missing_p(klass, obj, vid, FALSE)) {
            id = rb_intern_str(vid);
            return mnew_missing(klass, obj, id, id, rb_cMethod);
        }
      undef:
        rb_name_err_raise("undefined singleton method `%1$s' for `%2$s'",
                          obj, vid);
    }
    if (NIL_P(klass = rb_singleton_class_get(obj)) ||
        UNDEFINED_METHOD_ENTRY_P(me = rb_method_entry_at(klass, id)) ||
        UNDEFINED_REFINED_METHOD_P(me->def)) {
        vid = ID2SYM(id);
        goto undef;
    }
    return mnew_from_me(me, klass, obj, id, rb_cMethod, FALSE);
}
singleton_methods(all=true) → array click to toggle source

Returns an array of the names of singleton methods for obj. If the optional all parameter is true, the list will include methods in modules included in obj. Only public and protected singleton methods are returned.

module Other
  def three() end
end

class Single
  def Single.four() end
end

a = Single.new

def a.one()
end

class << a
  include Other
  def two()
  end
end

Single.singleton_methods    #=> [:four]
a.singleton_methods(false)  #=> [:two, :one]
a.singleton_methods         #=> [:two, :one, :three]
VALUE
rb_obj_singleton_methods(int argc, const VALUE *argv, VALUE obj)
{
    VALUE recur, ary, klass, origin;
    struct method_entry_arg me_arg;
    struct rb_id_table *mtbl;

    if (argc == 0) {
	recur = Qtrue;
    }
    else {
	rb_scan_args(argc, argv, "01", &recur);
    }
    klass = CLASS_OF(obj);
    origin = RCLASS_ORIGIN(klass);
    me_arg.list = st_init_numtable();
    me_arg.recur = RTEST(recur);
    if (klass && FL_TEST(klass, FL_SINGLETON)) {
	if ((mtbl = RCLASS_M_TBL(origin)) != 0) rb_id_table_foreach(mtbl, method_entry_i, &me_arg);
	klass = RCLASS_SUPER(klass);
    }
    if (RTEST(recur)) {
	while (klass && (FL_TEST(klass, FL_SINGLETON) || RB_TYPE_P(klass, T_ICLASS))) {
	    if (klass != origin && (mtbl = RCLASS_M_TBL(klass)) != 0) rb_id_table_foreach(mtbl, method_entry_i, &me_arg);
	    klass = RCLASS_SUPER(klass);
	}
    }
    ary = rb_ary_new();
    st_foreach(me_arg.list, ins_methods_i, ary);
    st_free_table(me_arg.list);

    return ary;
}
sysread(io, size) click to toggle source

cgi_runner.rb – CGI launcher.

Author: IPR – Internet Programming with Ruby – writers Copyright © 2000 TAKAHASHI Masayoshi, GOTOU YUUZOU Copyright © 2002 Internet Programming with Ruby writers. All rights reserved.

$IPR: cgi_runner.rb,v 1.9 2002/09/25 11:33:15 gotoyuzo Exp $

# File lib/webrick/httpservlet/cgi_runner.rb, line 11
def sysread(io, size)
  buf = ""
  while size > 0
    tmp = io.sysread(size)
    buf << tmp
    size -= tmp.bytesize
  end
  return buf
end
taint → obj click to toggle source

Mark the object as tainted.

Objects that are marked as tainted will be restricted from various built-in methods. This is to prevent insecure data, such as command-line arguments or strings read from Kernel#gets, from inadvertently compromising the user's system.

To check whether an object is tainted, use tainted?.

You should only untaint a tainted object if your code has inspected it and determined that it is safe. To do so use untaint.

VALUE
rb_obj_taint(VALUE obj)
{
    if (!OBJ_TAINTED(obj) && OBJ_TAINTABLE(obj)) {
        rb_check_frozen(obj);
        OBJ_TAINT(obj);
    }
    return obj;
}
tainted? → true or false click to toggle source

Returns true if the object is tainted.

See taint for more information.

VALUE
rb_obj_tainted(VALUE obj)
{
    if (OBJ_TAINTED(obj))
        return Qtrue;
    return Qfalse;
}
tap{|x|...} → obj click to toggle source

Yields self to the block, and then returns self. The primary purpose of this method is to “tap into” a method chain, in order to perform operations on intermediate results within the chain.

(1..10)                .tap {|x| puts "original: #{x.inspect}"}
  .to_a                .tap {|x| puts "array: #{x.inspect}"}
  .select {|x| x%2==0} .tap {|x| puts "evens: #{x.inspect}"}
  .map {|x| x*x}       .tap {|x| puts "squares: #{x.inspect}"}
VALUE
rb_obj_tap(VALUE obj)
{
    rb_yield(obj);
    return obj;
}
timeout(*args, &block) click to toggle source
# File lib/timeout.rb, line 117
def timeout(*args, &block)
  warn "#{caller_locations(1, 1)[0]}: Object##{__method__} is deprecated, use Timeout.timeout instead."
  Timeout.timeout(*args, &block)
end
to_enum(method = :each, *args) → enum click to toggle source
to_enum(method = :each, *args) {|*args| block} → enum

Creates a new Enumerator which will enumerate by calling method on obj, passing args if any.

If a block is given, it will be used to calculate the size of the enumerator without the need to iterate it (see Enumerator#size).

Examples

str = "xyz"

enum = str.enum_for(:each_byte)
enum.each { |b| puts b }
# => 120
# => 121
# => 122

# protect an array from being modified by some_method
a = [1, 2, 3]
some_method(a.to_enum)

It is typical to call #to_enum when defining methods for a generic Enumerable, in case no block is passed.

Here is such an example, with parameter passing and a sizing block:

module Enumerable
  # a generic method to repeat the values of any enumerable
  def repeat(n)
    raise ArgumentError, "#{n} is negative!" if n < 0
    unless block_given?
      return to_enum(__method__, n) do # __method__ is :repeat here
        sz = size     # Call size and multiply by n...
        sz * n if sz  # but return nil if size itself is nil
      end
    end
    each do |*val|
      n.times { yield *val }
    end
  end
end

%[hello world].repeat(2) { |w| puts w }
  # => Prints 'hello', 'hello', 'world', 'world'
enum = (1..14).repeat(3)
  # => returns an Enumerator when called without a block
enum.first(4) # => [1, 1, 1, 2]
enum.size # => 42
static VALUE
obj_to_enum(int argc, VALUE *argv, VALUE obj)
{
    VALUE enumerator, meth = sym_each;

    if (argc > 0) {
        --argc;
        meth = *argv++;
    }
    enumerator = rb_enumeratorize_with_size(obj, meth, argc, argv, 0);
    if (rb_block_given_p()) {
        enumerator_ptr(enumerator)->size = rb_block_proc();
    }
    return enumerator;
}
to_s → string click to toggle source

Returns a string representing obj. The default to_s prints the object's class and an encoding of the object id. As a special case, the top-level object that is the initial execution context of Ruby programs returns “main''.

VALUE
rb_any_to_s(VALUE obj)
{
    VALUE str;
    VALUE cname = rb_class_name(CLASS_OF(obj));

    str = rb_sprintf("#<%"PRIsVALUE":%p>", cname, (void*)obj);
    OBJ_INFECT(str, obj);

    return str;
}
to_yaml(options = {})
Alias for: psych_to_yaml
trust → obj click to toggle source

Deprecated method that is equivalent to untaint.

VALUE
rb_obj_trust(VALUE obj)
{
    rb_warning("trust is deprecated and its behavior is same as untaint");
    return rb_obj_untaint(obj);
}
unknown() click to toggle source

mathn

mathn serves to make mathematical operations more precise in Ruby and to integrate other mathematical standard libraries.

Without mathn:

3 / 2 => 1 # Integer

With mathn:

3 / 2 => 3/2 # Rational

mathn keeps value in exact terms.

Without mathn:

20 / 9 * 3 * 14 / 7 * 3 / 2 # => 18

With mathn:

20 / 9 * 3 * 14 / 7 * 3 / 2 # => 20

When you require 'mathn', the libraries for Prime, CMath, Matrix and Vector are also loaded.

Author: Keiju ISHITSUKA (SHL Japan Inc.)

# File lib/mathn.rb, line 40
warn('lib/mathn.rb is deprecated') if $VERBOSE
untaint → obj click to toggle source

Removes the tainted mark from the object.

See taint for more information.

VALUE
rb_obj_untaint(VALUE obj)
{
    if (OBJ_TAINTED(obj)) {
        rb_check_frozen(obj);
        FL_UNSET(obj, FL_TAINT);
    }
    return obj;
}
untrust → obj click to toggle source

Deprecated method that is equivalent to taint.

VALUE
rb_obj_untrust(VALUE obj)
{
    rb_warning("untrust is deprecated and its behavior is same as taint");
    return rb_obj_taint(obj);
}
untrusted? → true or false click to toggle source

Deprecated method that is equivalent to tainted?.

VALUE
rb_obj_untrusted(VALUE obj)
{
    rb_warning("untrusted? is deprecated and its behavior is same as tainted?");
    return rb_obj_tainted(obj);
}
xmp(exps, bind = nil) click to toggle source

A convenience method that's only available when the you require the IRB::XMP standard library.

Creates a new XMP object, using the given expressions as the exps parameter, and optional binding as bind or uses the top-level binding. Then evaluates the given expressions using the :XMP prompt mode.

For example:

require 'irb/xmp'
ctx = binding
xmp 'foo = "bar"', ctx
#=> foo = "bar"
  #==>"bar"
ctx.eval 'foo'
#=> "bar"

See XMP.new for more information.

# File lib/irb/xmp.rb, line 164
def xmp(exps, bind = nil)
  bind = IRB::Frame.top(1) unless bind
  xmp = XMP.new(bind)
  xmp.puts exps
  xmp
end