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Returns the next-larger representable Float.

These examples show the internally stored values (64-bit hexadecimal) for each Float f and for the corresponding f.next_float:

f = 0.0      # 0x0000000000000000
f.next_float # 0x0000000000000001

f = 0.01     # 0x3f847ae147ae147b
f.next_float # 0x3f847ae147ae147c

In the remaining examples here, the output is shown in the usual way (result to_s):

0.01.next_float    # => 0.010000000000000002
1.0.next_float     # => 1.0000000000000002
100.0.next_float   # => 100.00000000000001

f = 0.01
(0..3).each_with_index {|i| printf "%2d %-20a %s\n", i, f, f.to_s; f = f.next_float }

Output:

 0 0x1.47ae147ae147bp-7 0.01
 1 0x1.47ae147ae147cp-7 0.010000000000000002
 2 0x1.47ae147ae147dp-7 0.010000000000000004
 3 0x1.47ae147ae147ep-7 0.010000000000000005

f = 0.0; 100.times { f += 0.1 }
f                           # => 9.99999999999998       # should be 10.0 in the ideal world.
10-f                        # => 1.9539925233402755e-14 # the floating point error.
10.0.next_float-10          # => 1.7763568394002505e-15 # 1 ulp (unit in the last place).
(10-f)/(10.0.next_float-10) # => 11.0                   # the error is 11 ulp.
(10-f)/(10*Float::EPSILON)  # => 8.8                    # approximation of the above.
"%a" % 10                   # => "0x1.4p+3"
"%a" % f                    # => "0x1.3fffffffffff5p+3" # the last hex digit is 5.  16 - 5 = 11 ulp.

Related: Float#prev_float

Returns the next-smaller representable Float.

These examples show the internally stored values (64-bit hexadecimal) for each Float f and for the corresponding f.pev_float:

f = 5e-324   # 0x0000000000000001
f.prev_float # 0x0000000000000000

f = 0.01     # 0x3f847ae147ae147b
f.prev_float # 0x3f847ae147ae147a

In the remaining examples here, the output is shown in the usual way (result to_s):

0.01.prev_float   # => 0.009999999999999998
1.0.prev_float    # => 0.9999999999999999
100.0.prev_float  # => 99.99999999999999

f = 0.01
(0..3).each_with_index {|i| printf "%2d %-20a %s\n", i, f, f.to_s; f = f.prev_float }

Output:

0 0x1.47ae147ae147bp-7 0.01
1 0x1.47ae147ae147ap-7 0.009999999999999998
2 0x1.47ae147ae1479p-7 0.009999999999999997
3 0x1.47ae147ae1478p-7 0.009999999999999995

Related: Float#next_float.

Like backtrace, but returns each line of the execution stack as a Thread::Backtrace::Location. Accepts the same arguments as backtrace.

f = Fiber.new { Fiber.yield }
f.resume
loc = f.backtrace_locations.first
loc.label  #=> "yield"
loc.path   #=> "test.rb"
loc.lineno #=> 1

Returns default external encoding.

The default external encoding is used by default for strings created from the following locations:

• CSV

• File data read from disk

• SDBM

• StringIO

• Zlib::GzipReader

• Zlib::GzipWriter

• String#inspect

• Regexp#inspect

While strings created from these locations will have this encoding, the encoding may not be valid. Be sure to check String#valid_encoding?.

File data written to disk will be transcoded to the default external encoding when written, if default_internal is not nil.

The default external encoding is initialized by the -E option. If -E isn’t set, it is initialized to UTF-8 on Windows and the locale on other operating systems.

Sets default external encoding. You should not set Encoding::default_external in ruby code as strings created before changing the value may have a different encoding from strings created after the value was changed., instead you should use ruby -E to invoke ruby with the correct default_external.

See Encoding::default_external for information on how the default external encoding is used.

Returns default internal encoding. Strings will be transcoded to the default internal encoding in the following places if the default internal encoding is not nil:

• CSV

• Etc.sysconfdir and Etc.systmpdir

• File data read from disk

• File names from Dir

• Integer#chr

• String#inspect and Regexp#inspect

• Strings returned from Readline

• Strings returned from SDBM

• Time#zone

• Values from ENV

• Values in ARGV including $PROGRAM_NAME

Additionally String#encode and String#encode! use the default internal encoding if no encoding is given.

The script encoding (__ENCODING__), not default_internal, is used as the encoding of created strings.

Encoding::default_internal is initialized with -E option or nil otherwise.

Sets default internal encoding or removes default internal encoding when passed nil. You should not set Encoding::default_internal in ruby code as strings created before changing the value may have a different encoding from strings created after the change. Instead you should use ruby -E to invoke ruby with the correct default_internal.

See Encoding::default_internal for information on how the default internal encoding is used.

Iterates the given block for each element with an index, which starts from offset. If no block is given, returns a new Enumerator that includes the index, starting from offset

offset

the starting index to use

Iterates the given block for each element with an arbitrary object, obj, and returns obj

If no block is given, returns a new Enumerator.

Example

to_three = Enumerator.new do |y|
  3.times do |x|
    y << x
  end
end

to_three_with_string = to_three.with_object("foo")
to_three_with_string.each do |x,string|
  puts "#{string}: #{x}"
end

# => foo: 0
# => foo: 1
# => foo: 2

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

Processes a string returned by message.

It may add the class name of the exception to the end of the first line. Also, when highlight keyword is true, it adds ANSI escape sequences to make the message bold.

If you override this method, it must be tolerant for unknown keyword arguments. All keyword arguments passed to full_message are delegated to this method.

This method is overridden by did_you_mean and error_highlight to add their information.

A user-defined exception class can also define their own detailed_message method to add supplemental information. When highlight is true, it can return a string containing escape sequences, but use widely-supported ones. It is recommended to limit the following codes:

• Reset (\e[0m)

• Bold (\e[1m)

• Underline (\e[4m)

• Foreground color except white and black

  • Red (\e[31m)

  • Green (\e[32m)

  • Yellow (\e[33m)

  • Blue (\e[34m)

  • Magenta (\e[35m)

  • Cyan (\e[36m)

Use escape sequences carefully even if highlight is true. Do not use escape sequences to express essential information; the message should be readable even if all escape sequences are ignored.

Returns formatted string of exception. The returned string is formatted using the same format that Ruby uses when printing an uncaught exceptions to stderr.

If highlight is true the default error handler will send the messages to a tty.

order must be either of :top or :bottom, and places the error message and the innermost backtrace come at the top or the bottom.

The default values of these options depend on $stderr and its tty? at the timing of a call.

Returns any backtrace associated with the exception. This method is similar to Exception#backtrace, but the backtrace is an array of Thread::Backtrace::Location.

This method is not affected by Exception#set_backtrace().

See as_json.

Return true if the caused method was called as private.

When this module is included in another, Ruby calls append_features in this module, passing it the receiving module in mod. Ruby’s default implementation is to add the constants, methods, and module variables of this module to mod if this module has not already been added to mod or one of its ancestors. See also Module#include.

When this module is prepended in another, Ruby calls prepend_features in this module, passing it the receiving module in mod. Ruby’s default implementation is to overlay the constants, methods, and module variables of this module to mod if this module has not already been added to mod or one of its ancestors. See also Module#prepend.

Returns an array of all modules used in the current scope. The ordering of modules in the resulting array is not defined.

module A
  refine Object do
  end
end

module B
  refine Object do
  end
end

using A
using B
p Module.used_refinements

produces:

[#<refinement:Object@B>, #<refinement:Object@A>]

Creates instance variables and corresponding methods that return the value of each instance variable. Equivalent to calling “attr:name” on each name in turn. String arguments are converted to symbols. Returns an array of defined method names as symbols.

Creates an accessor method to allow assignment to the attribute symbol.id2name. String arguments are converted to symbols. Returns an array of defined method names as symbols.

Defines a named attribute for this module, where the name is symbol.id2name, creating an instance variable (@name) and a corresponding access method to read it. Also creates a method called name= to set the attribute. String arguments are converted to symbols. Returns an array of defined method names as symbols.

module Mod
  attr_accessor(:one, :two) #=> [:one, :one=, :two, :two=]
end
Mod.instance_methods.sort   #=> [:one, :one=, :two, :two=]

Makes a list of existing constants private.

Makes a list of existing constants deprecated. Attempt to refer to them will produce a warning.

module HTTP
  NotFound = Exception.new
  NOT_FOUND = NotFound # previous version of the library used this name

  deprecate_constant :NOT_FOUND
end

HTTP::NOT_FOUND
# warning: constant HTTP::NOT_FOUND is deprecated

See as_json.