Used to raise parsing and loading errors
Raised by Gem::Validator
when something is not right in a gem.
Raised to indicate that a system exit should occur with the specified exit_code
The Specification
class contains the information for a Gem. Typically defined in a .gemspec file or a Rakefile, and looks like this:
Gem::Specification.new do |s| s.name = 'example' s.version = '0.1.0' s.licenses = ['MIT'] s.summary = "This is an example!" s.description = "Much longer explanation of the example!" s.authors = ["Ruby Coder"] s.email = 'rubycoder@example.com' s.files = ["lib/example.rb"] s.homepage = 'https://rubygems.org/gems/example' s.metadata = { "source_code_uri" => "https://github.com/example/example" } end
Starting in RubyGems 2.0, a Specification
can hold arbitrary metadata. See metadata
for restrictions on the format and size of metadata items you may add to a specification.
Gem::StubSpecification
reads the stub: line from the gemspec. This prevents us having to eval the entire gemspec in order to find out certain information.
Net::HTTP
exception class. You cannot use Net::HTTPExceptions
directly; instead, you must use its subclasses.
Mixin methods for install and update options for Gem::Commands
Mixin methods for security option for Gem::Commands
A complex number can be represented as a paired real number with imaginary unit; a+bi. Where a is real part, b is imaginary part and i is imaginary unit. Real a equals complex a+0i mathematically.
Complex
object can be created as literal, and also by using Kernel#Complex
, Complex::rect
, Complex::polar
or to_c
method.
2+1i #=> (2+1i) Complex(1) #=> (1+0i) Complex(2, 3) #=> (2+3i) Complex.polar(2, 3) #=> (-1.9799849932008908+0.2822400161197344i) 3.to_c #=> (3+0i)
You can also create complex object from floating-point numbers or strings.
Complex(0.3) #=> (0.3+0i) Complex('0.3-0.5i') #=> (0.3-0.5i) Complex('2/3+3/4i') #=> ((2/3)+(3/4)*i) Complex('1@2') #=> (-0.4161468365471424+0.9092974268256817i) 0.3.to_c #=> (0.3+0i) '0.3-0.5i'.to_c #=> (0.3-0.5i) '2/3+3/4i'.to_c #=> ((2/3)+(3/4)*i) '1@2'.to_c #=> (-0.4161468365471424+0.9092974268256817i)
A complex object is either an exact or an inexact number.
Complex(1, 1) / 2 #=> ((1/2)+(1/2)*i) Complex(1, 1) / 2.0 #=> (0.5+0.5i)
A File
is an abstraction of any file object accessible by the program and is closely associated with class IO
. File
includes the methods of module FileTest
as class methods, allowing you to write (for example) File.exist?("foo")
.
In the description of File
methods, permission bits are a platform-specific set of bits that indicate permissions of a file. On Unix-based systems, permissions are viewed as a set of three octets, for the owner, the group, and the rest of the world. For each of these entities, permissions may be set to read, write, or execute the file:
The permission bits 0644
(in octal) would thus be interpreted as read/write for owner, and read-only for group and other. Higher-order bits may also be used to indicate the type of file (plain, directory, pipe, socket, and so on) and various other special features. If the permissions are for a directory, the meaning of the execute bit changes; when set the directory can be searched.
On non-Posix operating systems, there may be only the ability to make a file read-only or read-write. In this case, the remaining permission bits will be synthesized to resemble typical values. For instance, on Windows NT the default permission bits are 0644
, which means read/write for owner, read-only for all others. The only change that can be made is to make the file read-only, which is reported as 0444
.
Various constants for the methods in File
can be found in File::Constants
.
Raised when a method is called on a receiver which doesn’t have it defined and also fails to respond with method_missing
.
"hello".to_ary
raises the exception:
NoMethodError: undefined method `to_ary' for "hello":String