Installs a gem along with all its dependencies from local and remote gems.
Raised when trying to activate a gem, and that gem does not exist on the system. Instead of rescuing from this class, make sure to rescue from the superclass Gem::LoadError
to catch all types of load errors.
Raised when trying to activate a gem, and the gem exists on the system, but not the requested version. Instead of rescuing from this class, make sure to rescue from the superclass Gem::LoadError
to catch all types of load errors.
Raised when removing a gem with the uninstall command fails
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
Holds Integer
values. You cannot add a singleton method to an Integer
object, any attempt to do so will raise a TypeError
.
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
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!