Results for: "String#[]"

The installer installs the files contained in the .gem into the Gem.home.

Gem::Installer does the work of putting files in all the right places on the filesystem including unpacking the gem into its gem dir, installing the gemspec in the specifications dir, storing the cached gem in the cache dir, and installing either wrappers or symlinks for executables.

The installer invokes pre and post install hooks. Hooks can be added either through a rubygems_plugin.rb file in an installed gem or via a rubygems/defaults/#{RUBY_ENGINE}.rb or rubygems/defaults/operating_system.rb file. See Gem.pre_install and Gem.post_install for details.

An Uninstaller.

The uninstaller fires pre and post uninstall hooks. Hooks can be added either through a rubygems_plugin.rb file in an installed gem or via a rubygems/defaults/#{RUBY_ENGINE}.rb or rubygems/defaults/operating_system.rb file. See Gem.pre_uninstall and Gem.post_uninstall for details.

Gem::StreamUI implements a simple stream based user interface.

Not a URI.

This module provides instance methods for a digest implementation object to calculate message digest values.

Used to construct C classes (CUnion, CStruct, etc)

Fiddle::Importer#struct and Fiddle::Importer#union wrap this functionality in an easy-to-use manner.

Mixin methods for install and update options for Gem::Commands

When rubygems/test_case is required the default user interaction is a MockGemUi.

Module that defines the default UserInteraction. Any class including this module will have access to the ui method that returns the default UI.

UserInteraction allows RubyGems to interact with the user through standard methods that can be replaced with more-specific UI methods for different displays.

Since UserInteraction dispatches to a concrete UI class you may need to reference other classes for specific behavior such as Gem::ConsoleUI or Gem::SilentUI.

Example:

class X
  include Gem::UserInteraction

  def get_answer
    n = ask("What is the meaning of life?")
  end
end

Defines ParserWriterChooseMixin, which makes it possible to choose a different XMLWriter and/or XMLParser then the default one.

The Mixin is used in client.rb (class XMLRPC::Client) and server.rb (class XMLRPC::BasicServer)

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
puts 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 and duplication.

Integer.new(1)   #=> NoMethodError: undefined method `new' for Integer:Class
1.dup            #=> TypeError: can't dup Fixnum

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

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 "\n#{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

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!

Raised by exit to initiate the termination of the script.

Raised with the interrupt signal is received, typically because the user pressed on 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.

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

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

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'