Results for: "String# "

PrettyPrint::SingleLine

PrettyPrint::SingleLine is used by PrettyPrint.singleline_format

It is passed to be similar to a PrettyPrint object itself, by responding to:

but instead, the output has no line breaks

Prism::InstanceVariableReadNode

Represents referencing an instance variable.

@foo
^^^^

Prism::InstanceVariableTargetNode

Represents writing to an instance variable in a context that doesn’t have an explicit value.

@foo, @bar = baz
^^^^  ^^^^

Prism::InterpolatedMatchLastLineNode

Represents a regular expression literal that contains interpolation that is being used in the predicate of a conditional to implicitly match against the last line read by an IO object.

if /foo #{bar} baz/ then end
   ^^^^^^^^^^^^^^^^

Reline::KillRing

No documentation available

Rinda::RingServer

A RingServer allows a Rinda::TupleSpace to be located via UDP broadcasts. Default service location uses the following steps:

  1. A RingServer begins listening on the network broadcast UDP address.

  2. A RingFinger sends a UDP packet containing the DRb URI where it will listen for a reply.

  3. The RingServer receives the UDP packet and connects back to the provided DRb URI with the DRb service.

A RingServer requires a TupleSpace:

ts = Rinda::TupleSpace.new
rs = Rinda::RingServer.new

RingServer can also listen on multicast addresses for announcements. This allows multiple RingServers to run on the same host. To use network broadcast and multicast:

ts = Rinda::TupleSpace.new
rs = Rinda::RingServer.new ts, %w[Socket::INADDR_ANY, 239.0.0.1 ff02::1]

Rinda::RingProvider

RingProvider uses a RingServer advertised TupleSpace as a name service. TupleSpace clients can register themselves with the remote TupleSpace and look up other provided services via the remote TupleSpace.

Services are registered with a tuple of the format [:name, klass, DRbObject, description].

SyntaxSuggest::PriorityEngulfQueue

Keeps track of what elements are in the queue in priority and also ensures that when one element engulfs/covers/eats another that the larger element evicts the smaller element

RubyVM::AbstractSyntaxTree

AbstractSyntaxTree provides methods to parse Ruby code into abstract syntax trees. The nodes in the tree are instances of RubyVM::AbstractSyntaxTree::Node.

This module is MRI specific as it exposes implementation details of the MRI abstract syntax tree.

This module is experimental and its API is not stable, therefore it might change without notice. As examples, the order of children nodes is not guaranteed, the number of children nodes might change, there is no way to access children nodes by name, etc.

If you are looking for a stable API or an API working under multiple Ruby implementations, consider using the parser gem or Ripper. If you would like to make RubyVM::AbstractSyntaxTree stable, please join the discussion at bugs.ruby-lang.org/issues/14844.

OpenSSL::Buffering

OpenSSL IO buffering mix-in module.

This module allows an OpenSSL::SSL::SSLSocket to behave like an IO.

You typically won’t use this module directly, you can see it implemented in OpenSSL::SSL::SSLSocket.

Integer

An Integer object represents an integer value.

You can create an Integer object explicitly with:

You can convert certain objects to Integers with:

An attempt to add a singleton method to an instance of this class causes an exception to be raised.

What’s Here

First, what’s elsewhere. Class Integer:

Here, class Integer provides methods for:

Querying

Comparing

Converting

Other

Refinement

No documentation available

Numeric

Numeric is the class from which all higher-level numeric classes should inherit.

Numeric allows instantiation of heap-allocated objects. Other core numeric classes such as Integer are implemented as immediates, which means that each Integer is a single immutable object which is always passed by value.

a = 1
1.object_id == a.object_id   #=> true

There can only ever be one instance of the integer 1, for example. Ruby ensures this by preventing instantiation. If duplication is attempted, the same instance is returned.

Integer.new(1)                   #=> NoMethodError: undefined method `new' for Integer:Class
1.dup                            #=> 1
1.object_id == 1.dup.object_id   #=> true

For this reason, Numeric should be used when defining other numeric classes.

Classes which inherit from Numeric must implement coerce, which returns a two-member Array containing an object that has been coerced into an instance of the new class and self (see coerce).

Inheriting classes should also implement arithmetic operator methods (+, -, * and /) and the <=> operator (see Comparable). These methods may rely on coerce to ensure interoperability with instances of other numeric classes.

class Tally < Numeric
  def initialize(string)
    @string = string
  end

  def to_s
    @string
  end

  def to_i
    @string.size
  end

  def coerce(other)
    [self.class.new('|' * other.to_i), self]
  end

  def <=>(other)
    to_i <=> other.to_i
  end

  def +(other)
    self.class.new('|' * (to_i + other.to_i))
  end

  def -(other)
    self.class.new('|' * (to_i - other.to_i))
  end

  def *(other)
    self.class.new('|' * (to_i * other.to_i))
  end

  def /(other)
    self.class.new('|' * (to_i / other.to_i))
  end
end

tally = Tally.new('||')
puts tally * 2            #=> "||||"
puts tally > 1            #=> true

What’s Here

First, what’s elsewhere. Class Numeric:

Here, class Numeric provides methods for:

Querying

Comparing

Converting

Other

Continuation

Continuation objects are generated by Kernel#callcc, after having +require+d continuation. They hold a return address and execution context, allowing a nonlocal return to the end of the callcc block from anywhere within a program. Continuations are somewhat analogous to a structured version of C’s setjmp/longjmp (although they contain more state, so you might consider them closer to threads).

For instance:

require "continuation"
arr = [ "Freddie", "Herbie", "Ron", "Max", "Ringo" ]
callcc{|cc| $cc = cc}
puts(message = arr.shift)
$cc.call unless message =~ /Max/

produces:

Freddie
Herbie
Ron
Max

Also you can call callcc in other methods:

require "continuation"

def g
  arr = [ "Freddie", "Herbie", "Ron", "Max", "Ringo" ]
  cc = callcc { |cc| cc }
  puts arr.shift
  return cc, arr.size
end

def f
  c, size = g
  c.call(c) if size > 1
end

f

This (somewhat contrived) example allows the inner loop to abandon processing early:

require "continuation"
callcc {|cont|
  for i in 0..4
    print "#{i}: "
    for j in i*5...(i+1)*5
      cont.call() if j == 17
      printf "%3d", j
    end
  end
}
puts

produces:

0:   0  1  2  3  4
1:   5  6  7  8  9
2:  10 11 12 13 14
3:  15 16

StopIteration

Raised to stop the iteration, in particular by Enumerator#next. It is rescued by Kernel#loop.

loop do
  puts "Hello"
  raise StopIteration
  puts "World"
end
puts "Done!"

produces:

Hello
Done!

SystemExit

Raised by exit to initiate the termination of the script.

Interrupt

Raised when the interrupt signal is received, typically because the user has pressed Control-C (on most posix platforms). As such, it is a subclass of SignalException.

begin
  puts "Press ctrl-C when you get bored"
  loop {}
rescue Interrupt => e
  puts "Note: You will typically use Signal.trap instead."
end

produces:

Press ctrl-C when you get bored

then waits until it is interrupted with Control-C and then prints:

Note: You will typically use Signal.trap instead.

StandardError

The most standard error types are subclasses of StandardError. A rescue clause without an explicit Exception class will rescue all StandardErrors (and only those).

def foo
  raise "Oups"
end
foo rescue "Hello"   #=> "Hello"

On the other hand:

require 'does/not/exist' rescue "Hi"

raises the exception:

LoadError: no such file to load -- does/not/exist

IndexError

Raised when the given index is invalid.

a = [:foo, :bar]
a.fetch(0)   #=> :foo
a[4]         #=> nil
a.fetch(4)   #=> IndexError: index 4 outside of array bounds: -2...2

RangeError

Raised when a given numerical value is out of range.

[1, 2, 3].drop(1 << 100)

raises the exception:

RangeError: bignum too big to convert into `long'

ScriptError

ScriptError is the superclass for errors raised when a script can not be executed because of a LoadError, NotImplementedError or a SyntaxError. Note these type of ScriptErrors are not StandardError and will not be rescued unless it is specified explicitly (or its ancestor Exception).

SecurityError

No longer used by internal code.

SystemCallError

SystemCallError is the base class for all low-level platform-dependent errors.

The errors available on the current platform are subclasses of SystemCallError and are defined in the Errno module.

File.open("does/not/exist")

raises the exception:

Errno::ENOENT: No such file or directory - does/not/exist

Range

A Range object represents a collection of values that are between given begin and end values.

You can create an Range object explicitly with:

A range may be created using method Range.new:

# Ranges that by default include the given end value.
Range.new(1, 4).to_a     # => [1, 2, 3, 4]
Range.new('a', 'd').to_a # => ["a", "b", "c", "d"]
# Ranges that use third argument +exclude_end+ to exclude the given end value.
Range.new(1, 4, true).to_a     # => [1, 2, 3]
Range.new('a', 'd', true).to_a # => ["a", "b", "c"]

Beginless Ranges

A beginless range has a definite end value, but a nil begin value. Such a range includes all values up to the end value.

r = (..4)               # => nil..4
r.begin                 # => nil
r.include?(-50)         # => true
r.include?(4)           # => true

r = (...4)              # => nil...4
r.include?(4)           # => false

Range.new(nil, 4)       # => nil..4
Range.new(nil, 4, true) # => nil...4

A beginless range may be used to slice an array:

a = [1, 2, 3, 4]
r = (..2) # => nil...2
a[r]      # => [1, 2]

Method each for a beginless range raises an exception.

Endless Ranges

An endless range has a definite begin value, but a nil end value. Such a range includes all values from the begin value.

r = (1..)         # => 1..
r.end             # => nil
r.include?(50)    # => true

Range.new(1, nil) # => 1..

The literal for an endless range may be written with either two dots or three. The range has the same elements, either way. But note that the two are not equal:

r0 = (1..)           # => 1..
r1 = (1...)          # => 1...
r0.begin == r1.begin # => true
r0.end == r1.end     # => true
r0 == r1             # => false

An endless range may be used to slice an array:

a = [1, 2, 3, 4]
r = (2..) # => 2..
a[r]      # => [3, 4]

Method each for an endless range calls the given block indefinitely:

a = []
r = (1..)
r.each do |i|
  a.push(i) if i.even?
  break if i > 10
end
a # => [2, 4, 6, 8, 10]

A range can be both beginless and endless. For literal beginless, endless ranges, at least the beginning or end of the range must be given as an explicit nil value. It is recommended to use an explicit nil beginning and implicit nil end, since that is what Ruby uses for Range#inspect:

(nil..)    # => (nil..)
(..nil)    # => (nil..)
(nil..nil) # => (nil..)

Ranges and Other Classes

An object may be put into a range if its class implements instance method <=>. Ruby core classes that do so include Array, Complex, File::Stat, Float, Integer, Kernel, Module, Numeric, Rational, String, Symbol, and Time.

Example:

t0 = Time.now         # => 2021-09-19 09:22:48.4854986 -0500
t1 = Time.now         # => 2021-09-19 09:22:56.0365079 -0500
t2 = Time.now         # => 2021-09-19 09:23:08.5263283 -0500
(t0..t2).include?(t1) # => true
(t0..t1).include?(t2) # => false

A range can be iterated over only if its elements implement instance method succ. Ruby core classes that do so include Integer, String, and Symbol (but not the other classes mentioned above).

Iterator methods include:

Example:

a = []
(1..4).each {|i| a.push(i) }
a # => [1, 2, 3, 4]

Ranges and User-Defined Classes

A user-defined class that is to be used in a range must implement instance <=>; see Integer#<=>. To make iteration available, it must also implement instance method succ; see Integer#succ.

The class below implements both <=> and succ, and so can be used both to construct ranges and to iterate over them. Note that the Comparable module is included so the == method is defined in terms of <=>.

# Represent a string of 'X' characters.
class Xs
  include Comparable
  attr_accessor :length
  def initialize(n)
    @length = n
  end
  def succ
    Xs.new(@length + 1)
  end
  def <=>(other)
    @length <=> other.length
  end
  def to_s
    sprintf "%2d #{inspect}", @length
  end
  def inspect
    'X' * @length
  end
end

r = Xs.new(3)..Xs.new(6) #=> XXX..XXXXXX
r.to_a                   #=> [XXX, XXXX, XXXXX, XXXXXX]
r.include?(Xs.new(5))    #=> true
r.include?(Xs.new(7))    #=> false

What’s Here

First, what’s elsewhere. Class Range:

Here, class Range provides methods that are useful for:

Methods for Creating a Range

Methods for Querying

Methods for Comparing

Methods for Iterating

Methods for Converting

Methods for Working with JSON

To make these methods available:

require 'json/add/range'

Ripper

Ripper is a Ruby script parser.

You can get information from the parser with event-based style. Information such as abstract syntax trees or simple lexical analysis of the Ruby program.

Usage

Ripper provides an easy interface for parsing your program into a symbolic expression tree (or S-expression).

Understanding the output of the parser may come as a challenge, it’s recommended you use PP to format the output for legibility.

require 'ripper'
require 'pp'

pp Ripper.sexp('def hello(world) "Hello, #{world}!"; end')
  #=> [:program,
       [[:def,
         [:@ident, "hello", [1, 4]],
         [:paren,
          [:params, [[:@ident, "world", [1, 10]]], nil, nil, nil, nil, nil, nil]],
         [:bodystmt,
          [[:string_literal,
            [:string_content,
             [:@tstring_content, "Hello, ", [1, 18]],
             [:string_embexpr, [[:var_ref, [:@ident, "world", [1, 27]]]]],
             [:@tstring_content, "!", [1, 33]]]]],
          nil,
          nil,
          nil]]]]

You can see in the example above, the expression starts with :program.

From here, a method definition at :def, followed by the method’s identifier :@ident. After the method’s identifier comes the parentheses :paren and the method parameters under :params.

Next is the method body, starting at :bodystmt (stmt meaning statement), which contains the full definition of the method.

In our case, we’re simply returning a String, so next we have the :string_literal expression.

Within our :string_literal you’ll notice two @tstring_content, this is the literal part for Hello, and !. Between the two @tstring_content statements is a :string_embexpr, where embexpr is an embedded expression. Our expression consists of a local variable, or var_ref, with the identifier (@ident) of world.

Resources

Requirements

License

Ruby License.

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